Research and analysis

RIFE 30, Radioactivity in Food and the Environment, 2024

Updated 30 October 2025

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Foreword

The UK’s environmental regulators and food safety agencies are pleased to present the 30th edition of the Radioactivity in Food and the Environment (RIFE) report.

Radioactive substances have many beneficial uses, including their use in medical diagnostics and therapies and in power generation. They are unlikely to be harmful if controlled in the right way. Regulation aims to ensure these benefits, whilst keeping people and the environment safe. This regulation is embedded into relevant legislation, such as the Environmental Authorisations (Scotland) Regulations 2018, Environmental Permitting Regulations (England and Wales) 2016 and the Radioactive Substances (Modification of Enactments) Regulations (Northern Ireland) 2018. The independent monitoring of radioactivity in food and the environment is an important part of the regulatory process and provides reassurance to members of the public.

RIFE 30 sets out the findings of the monitoring programmes of radioactivity in food and the environment carried out in 2024 throughout the UK. These monitoring programmes are undertaken by the Environment Agency, Food Standards Agency, Food Standards Scotland, Natural Resources Wales, Northern Ireland Environment Agency, and the Scottish Environment Protection Agency.

The monitoring results and subsequent assessments presented in this report demonstrate that the exposure of members of the public to radiation, resulting from authorised discharges of radioactive waste and direct radiation, near nuclear and selected non-nuclear sites remained below the legal limit (1 milliSeivert) in 2024.

This report was compiled by the Centre for Environment, Fisheries and Aquaculture Science on behalf of the Environment Agency, Food Standards Agency, Food Standards Scotland, Natural Resources Wales, Northern Ireland Environment Agency and the Scottish Environment Protection Agency.

Requests for supporting documents and other information should be addressed to:

Or alternatively,

Food Standards Agency

Food Policy Division
11th Floor
64 Victoria Street
London
SW1E 6QP

Food Standards Scotland

4th Floor
Pilgrim House
Old Ford Road
Aberdeen
AB11 5RL

Cyfoeth Naturiol Cymru / Natural Resources Wales

Welsh Government Offices
Cathays Park
King Edward VII Avenue
Cardiff
CE10 3NQ

Northern Ireland Environment Agency

Industrial Pollution and Radiochemical Inspectorate
Klondyke Building
Cromac Avenue
Lower Ormeau Road
Belfast
BT7 2JA

The main report is split by nuclear sectors, each nuclear licensed site is allocated to a specific sector as given below.

Data in figures and tables

The tables (in ODS format) and the underlying data for the figures contained in this report are available from the main RIFE page.

1. Introduction

Overview

  • The Radioactivity in Food and the Environment (RIFE) report represents the collaboration between the UK’s environment and food standards agencies. The monitoring programme is independent of the nuclear industry.
  • The RIFE report provides a transparent check on food safety and the public’s exposure to radiation according to relevant UK legislation
  • The monitoring programme results support the UK in meeting its international treaty obligations.
  • Annual radiation doses are summarised for nuclear and selected non-nuclear sites; all doses were below the annual legal limit of 1 milliSievert in 2024.

This section:

  • describes the scope and purpose of the UK monitoring programmes
  • provides a summary of the key results in terms of radiation exposures at each nuclear and selected non-nuclear sites in 2024
  • gives an overview of the main sources of radiation in a regulatory context

1.1. Scope and purpose of the monitoring programmes

In England and Wales, the Food Standards Agency (FSA) and the Environment Agency[footnote 1] carry out food and environmental (including seawater, sediments, dose rate) monitoring, respectively. Scottish Environment Protection Agency (SEPA) (working closely with Food Standards Scotland (FSS) on its programme) and the Northern Ireland Environment Agency (NIEA) both undertake food and environmental monitoring in Scotland and Northern Ireland, respectively. Food monitoring includes the collection and analysis of cow’s milk (unless otherwise specified in this report). Surveillance of imports through points of entry continued in 2024. The regular national programme of monitoring of sources of drinking water, air and rain continued on behalf of the Department for Energy Security & Net Zero (DESNZ), NIEA and the Scottish Government. The FSA and SEPA (as part of the joint SEPA and FSS monitoring programme) also carry out UK monitoring of milk and canteen meals that are collected remotely from nuclear sites. Annual surveys of seas around the UK (including locations away from nuclear sites) are monitored on behalf of DESNZ. The Environment Agency, NIEA, Natural Resources Wales (NRW) and SEPA are collectively referred to as the UK environment agencies. FSA and FSS are collectively referred to as the UK food standards agencies.

The FSA has responsibility for food safety in England, Northern Ireland, and Wales, and FSS has this responsibility in Scotland. The environment agencies are responsible for regulating environmental protection in England, Northern Ireland, Wales, and Scotland, respectively. This includes the regulation of radioactive discharges and radioactive waste disposal from nuclear and non-nuclear sites.

The current UK legislation, relating to radioactivity, provides uniform safety standards to protect the health of workers and members of the public. These basic safety standards are retained from European Council Directives, the most recent one being the Basic Safety Standards Directive 2013 or ‘BSSD 13’ (European Commission 2014). This lays down basic safety standards for protecting people against the dangers arising from exposure to ionising radiation.

The RIFE report and the associated monitoring programmes were designed to conform to the requirements of Article 36 of the Euratom Treaty (see Section 8 and Appendix 1 in previous RIFE reports, for more details). Specifically, it provides estimates of annual doses to members of the public from authorised practices and enables these results to be made available to stakeholders. Following its withdrawal from the Euratom Treaty, the UK is no longer required to report these data to the European Commission and has agreed a Nuclear Cooperation Agreement (NCA) with the European Union (EU). This ensures both parties continue working together on civil nuclear matters including safeguards, safety, and security.

In late December 2020, DESNZ published its transboundary directions to the environment agencies, available from DESNZ Transboundary directions. These directions replace the requirements of Article 37 (related to the transboundary radiological impact of releases during normal operation) of the Euratom treaty following the UK withdrawal from the Euratom Treaty.

The Ionising Radiation (Basic Safety Standards) (Miscellaneous Provisions) (Amendment) (EU Exit) Regulations 2018 (UK Statutory Instruments 2018) came into force to transpose parts of BSSD 13, not already covered within existing statutory regimes. These regulations impose duties on appropriate ministers to ensure that certain functions are carried out in relation to exposures from:

  • contaminated land
  • exposures from buildings or contaminated commodities
  • to raise awareness and issue guidance about orphan sources (which are not under regulatory control but pose a radiological hazard – see Appendix 2 for definition).

The requirements for regulating public exposure from the disposal of radioactive waste in England and Wales are set out in the Environmental Permitting (England and Wales) Regulations 2016 (EPR 16) (United Kingdom - Parliament 2016), Schedule 23 ‘radioactive substances activities’. These regulations were amended in 2018 by the Environmental Permitting (England and Wales) (Amendment) (No. 2) Regulations 2018 (EPR 18) (United Kingdom - Parliament 2018) to transpose changes brought about by BSSD 13, and then by the Environmental Permitting (England and Wales) (Amendment) (EU Exit) Regulations 2019 (EPR 19) in 2019 (United Kingdom - Parliament 2020a). This was to ensure that the regulations remain fully operable at the end of the transition period following the UK’s exit from the EU. Further changes were made in the Waste and Environmental Permitting etc. (Legislative Functions and Amendment etc.) (EU Exit) Regulations 2020, which transferred some functions from the European Commission to the Secretary of State and the devolved administrations (United Kingdom - Parliament 2020b).

In 2018, the Radioactive Substances (Modification of Enactments) Regulations (Northern Ireland) 2018 (RSR 18) came into force for radioactive substances activities in Northern Ireland (Statutory Rules of Northern Ireland 2018) by amending the Radioactive Substances Act 1993 (RSA 93) (United Kingdom - Parliament 1993). A guidance document was also published in 2018, providing the scope of and exceptions from the radioactive substances legislation in England, Wales, and Northern Ireland (Department for Business Energy & Industrial Strategy and others 2018).

The requirements for regulating public exposure from the disposal of radioactive waste in Scotland is set out in the Environmental Authorisations (Scotland) Regulations 2018 (EASR18) (Scottish Government 2018), Schedule 8 ‘radioactive substances activities’. There are 4 types of authorisation under EASR18: general binding rules, notification, registration and permit (more information can be found at: SEPA environmental authorisations). EASR18 was amended in 2025 to provide an integrated authorisation framework, bringing together the authorisation, procedural and enforcement arrangements relating to water, waste management, industrial activities and radioactive substances.

To transpose the requirements of BSSD 13, the Ionising Radiations Regulations 2017 (IRR 17) (United Kingdom - Parliament 1999) came into force in 2018 (replacing the Ionising Radiations Regulations 1999). The Health and Safety Executive (HSE) has also provided practical advice (Code of Practice) to help operators comply with their duties under IRR 17 (Health and Safety Executive 2018). IRR 17 controls the radiation exposure of workers and the public apart from that resulting from the permitted disposal of radioactive waste, which is regulated by the environment agencies under the various permitting legislation described previously.

The Environment Agency, NRW and SEPA also have broader responsibilities under the Environment Act 1995 (United Kingdom - Parliament 1995a) for environmental protection including determining general concentrations of pollution in the environment.

The monitoring programmes have several purposes:

  • environmental and food results are used to estimate and assess dose to the public. This is to confirm that the controls and conditions placed in the authorisations or permits provide the necessary protection and to ensure compliance with legal dose limits
  • ongoing monitoring helps to establish the long-term trends in concentrations of radioactivity over time near, and at distance from, nuclear sites
  • the results are also used to confirm the safety of the food chain
  • monitoring the environment provides indicators of radionuclide dispersion around each nuclear site

Most of the monitoring carried out and presented in this report concerns the local effects of current and historical discharges from nuclear sites in the UK. Monitoring of food and the environment remote from nuclear sites is also carried out, giving information on background concentrations of radionuclides.

In previous years, the Environment Agency (with NRW providing advice on monitoring in Wales), the FSA, FSS and SEPA have all completed reviews of their environmental radioactivity monitoring programmes. Further information is available in earlier RIFE reports (for example, (Environment Agency and others 2020)). Reviews are carried out to ensure the monitoring programmes are appropriate and are consistent with advice in the agency technical guidance (Environment Agency, Food Standards Agency & Scottish Environment Protection Agency 2010; Scottish Environment Protection Agency 2019a), resulting in an adjustment and consolidation of the monitoring around some sites. Year on year, the monitoring programmes are also affected by sample availability.

The Environment Agency, FSA, FSS, NRW, NIEA, SEPA and DESNZ have produced 3 RIFE summary reports, which support the UK’s OSPAR and Joint Convention obligations, and these are available via the main RIFE report page. The most recent summary report was combined with the UK report on the application of Best Available Techniques (BAT) in civil nuclear facilities (2017 to 2021), which was submitted to the Radioactive Substances Committee of the OSPAR Commission as the UK statement on the implementation of OSPAR Recommendation 2018/1 on Radioactive Substances in early 2023 and is available at the following webpage - UK implementation reporting on the OSPAR website.

The analysis and measurements for the monitoring programmes was carried out by various UK laboratories, including those listed below. These laboratories also carried out most of the sample collection for the programmes:

  • Centre for Environment, Fisheries and Aquaculture Science (Cefas)
  • UK Health Security Agency (UKHSA)
  • SOCOTEC UK Limited

Details of the methods of sampling and analysis are presented in Section 2 of this report. Section 2 also explains how results are interpreted in terms of public radiation exposures. A summary of the assessment approach and current trends in doses is given in Section 1.2.

1.2. Summary of radiation doses

1.2.1. The assessment process

Most of the monitoring was carried out to determine the effects of discharges from nuclear and non-nuclear sites on the food people consume and their environment. The results are used to estimate and assess annual radiation doses to the public that can then be compared with the relevant dose limits. Dose assessments are retrospective in that they apply to 2024 using monitoring results for that year. The radioactivity concentrations and dose rates reported include the combined radiological impact of all discharges, up to the time of sampling.

In this report, 2 main types of retrospective doses are assessed, ‘total dose’ and source specific doses.

‘Total dose’ assessments consider the doses from radioactive discharges (gaseous and liquid) to the environment from nuclear sites combined with the dose from radiation sources on site (direct radiation). This assessment gives an estimate of the annual ‘total dose’ to people living near the nuclear sites. The ‘total dose’ assessment is the main method for estimating radiation exposure to the public.

Source specific assessments estimate the annual dose from individual sources and associated exposure pathways (see Appendix 2, and Appendix 5 for more information). These dose assessments provide reassurance on the robustness and reasonableness of the annual ‘total dose’ method (which is the preferred assessment type (Environment Agency, Scottish Environment Protection Agency and others 2012)) and provide information for a range of additional exposure pathways. The sum of the doses from specific sources (terrestrial and aquatic) cannot be directly compared to the assessment of ‘total dose’ from all sources. This is because the assessment methods use different ways of defining the most exposed people.

The sources considered, habits and monitoring data used, and the dose calculations are described in previous RIFE reports. The primary purpose of each assessment type is to assess the main sources of exposure at each site for comparison with the 1mSv limit.

Exposure from direct radiation may be a significant contributor to dose, close to a nuclear site, due to radiation emitting from sources on the site[footnote 2]. The Office for Nuclear Regulation (ONR) is responsible for regulating direct radiation. In 2018, Électricité de France (EDF) Energy revised its method of direct dose assessment (for the calendar year) for operating power stations based on measurements of external radiation dose rates at the site boundary, distances to the point of exposure and occupancy data (EDF Energy 2018). This is different to the previous method based on generic arguments considering the low dose rates from Advanced Gas-cooled Reactor (AGR) and Pressurised Water Reactor (PWR) power stations. Therefore, values since 2018 will differ from the generic values given previously. The operators of nuclear sites provide estimates of direct radiation doses to the ONR (Table 1.1); annual exposure data are then made available for use in ‘total dose’ assessments. These dose assessments use recent habits survey data which have been profiled using an agreed method (Camplin, Grzechnik & Smedley 2005). Data tables and the detailed results of the dose assessments, in Open Document Spreadsheet (ODS) format, are downloadable from the main RIFE page.

Both types of assessment consider those people in the population most exposed to radiation (the ‘representative person’). The results from both types of assessments are compared with legal limits (1mSv for members of the public and 50mSv specifically for skin exposure). The effective doses (defined in Appendix 2) are calculated and compared with the legal dose limit of 1mSv per year for members of the public. All legal radiation dose limits in the UK are based on recommendations made by the International Commission on Radiological Protection (ICRP) (International Commission on Radiological Protection 2007), which are consistent with Basic Safety Standards Directive 13 (European Commission 2014). The radiation dose specifically to skin is also assessed in some cases and compared with the legal limit for skin exposure.

The radiation doses resulting from human activities may be compared with the exposure from natural radioactivity. The average individual radiation dose in the UK population (in 2025) from natural radiation was estimated by UKHSA to be approximately 2.2mSv per year (UKHSA radiation and you).

Radiation exposures to some specific groups of workers are included in the assessment of doses from nuclear sites. These are people who may be inadvertently exposed because of their work. These, for example, include fishers, farmers, and sewage workers. It is appropriate to compare their doses to the dose limit for members of the public (Allott 2005). Those people who specifically work with ionising radiation have their radiation doses assessed and recorded as part of their employer’s programme to assess occupational exposure (United Kingdom - Parliament 2017).

1.2.2. ‘Total dose’ results for 2024

The results of the assessment for each site are summarised in Table 1.2 (see also Figure TS and Table S in the Technical Summary). These data are presented in 3 parts. The representative person receiving the highest annual doses from the pathways mainly relating to gaseous discharges and direct radiation are shown in part A and those for liquid discharges in part B. After selection, all other pathways are re-included. Occasionally, the people receiving the highest doses from all pathways and sources are different from those in parts A and B. Therefore, this case is presented in part C. After selection all pathways are re-included in the assessment. The major contributions to dose are provided. The use of radionuclide concentrations reported at the limits of detection provide an upper estimate of doses calculated for pathways based on these measurements. The full output from the assessment for each site can be provided by contacting one of the agencies listed in the Foreword of this report or downloaded from the main RIFE page.

In all cases, doses estimated for 2024 were much less than the annual limit of 1mSv for members of the public. The people most affected from gaseous discharges and direct radiation varied from site to site, but the dominant pathway was often direct radiation (from the relevant site), where it was applicable. The people most affected from liquid discharges were generally adults eating seafood or people who spend long periods of time over contaminated sediments, which are coastal or other areas that are impacted by liquid discharges.

The representative person who received the highest annual ‘total dose’ (0.22mSv), was by people living near the Capenhurst site and almost entirely due to direct radiation from the site. The next highest annual ‘total dose’ were received by the Cumbrian coastal community (near Sellafield)[footnote 3], who consumed crustaceans at high rates, together with other seafood (0.20mSv) and people living near the Grove Centre, Amersham (0.087mSv); this dose was almost entirely due to direct radiation from the site and was a small fraction of the dose limit.

Data for the time-series of annual ‘total dose’ from 2007 to 2024 is given in Table 1.3. In all cases, the assessed ‘total dose’ were less that the 1mSv dose limit to members of the public. Detailed plots and discussion on the trends are given in the relevant site sections and supporting texts.

1.2.4 Source specific dose results for 2024

The results of the source specific assessments for the sites assessed in the UK are summarised in Figure 1.1 and Table 1.4, which contains numerical data and the major contributors to dose. Figure 1.1 shows the assessed source specific doses for 2024, both from gaseous and liquid sources, compared to the 1mSv dose limit to members of the public. Doses ranged from less than 0.005mSv (at many sites) to 0.31mSv from all liquid sources along the Cumbrian Coast, including a significant contribution to the dose from historical discharges of naturally occurring radionuclides from the former phosphate processing plant at Whitehaven. These assessments focus on the effect of gaseous or liquid waste discharges, unlike the assessment of ‘total dose’ which includes all sources including the effect of direct radiation.

Figure 1.1(a). Source specific doses, in mSv y-1, from liquid discharges in the UK, 2024. (Exposures to the Cumbrian Coastal Community receive a significant contribution to the dose from historical discharges of naturally occurring radionuclides from the former phosphate processing plant at Whitehaven). Small doses less than or equal to 0.005mSv are recorded as being 0.005mSv.
Site name Dose from liquid discharges, mSv y-1
Cumbrian Coastal Community 0.31
Barrow 0.060
Berkeley and Oldbury 0.027
Heysham 0.020
Hinkley 0.014
Dungeness 0.011
Springfields 0.009
Dounreay 0.008
Hunterston 0.008
Rosyth 0.008
Capenhurst 0.007
Hartlepool 0.007
Trawsfynydd 0.007
Faslane 0.006
Aldermaston 0.005
Grove Centre, Amersham 0.005
Bradwell 0.005
Chapelcross 0.005
Derby 0.005
Devonport 0.005
Harwell 0.005
Sizewell 0.005
Torness 0.005
Winfrith 0.005
Wylfa 0.005
limit 1.0
Figure 1.1(b). Source specific doses, in mSv y-1, from gaseous discharges in the UK, 2024. Small doses less than or equal to 0.005mSv are recorded as being 0.005mSv.
Site name Dose from gaseous discharges, mSv y-1
Trawsfynydd 0.037
Dounreay 0.015
Grove Centre, Amersham 0.010
Sellafield 0.010
Hunterston 0.009
LLWR 0.009
Torness 0.007
Chapelcross 0.006
Aldermaston 0.005
Barrow 0.005
Berkeley and Oldbury 0.005
Bradwell 0.005
Capenhurst 0.005
Derby 0.005
Devonport 0.005
Dungeness 0.005
Faslane 0.005
Hartlepool 0.005
Harwell 0.005
Heysham 0.005
Hinkley 0.005
Sizewell 0.005
Springfields 0.005
Winfrith 0.005
Wylfa 0.005
limit 1.0

The most significant exposures from seafood (fish and crustacean shellfish) consumption were to the Cumbrian coastal community. The majority of the dose was from historical discharges of naturally occurring radionuclides from the former phosphate processing plant. The most important pathways and radionuclides at each site were similar to those found for ‘total dose’.

Although some source specific doses were estimated to be higher than the ‘total dose’ at some sites, the reasons for this are understood and relate to the different assumptions of the 2 assessment approaches. The assumptions used for source specific assessments are conservative with respect to adding together the effects of consumption of different foods. The assumptions used for ‘total dose’ assessments are more realistic, and the estimates from the source specific assessments provide reassurance that the ‘total dose’ approach is reasonable. Radiation doses to all age groups (see Section 2.6 for the age groups used), calculated using the source-specific method, were all found to be well below the legal limit of 1mSv per year.

1.2.5. Protecting the environment

This report focusses on the risk to the public to ensure that radiation doses remain below limits. However, the environment agencies also consider the protection of wildlife and the environment from radiation exposure caused by human activity. The 2007 recommendations of the ICRP concluded that a systematic approach to the radiological assessment of non-human species was required to support the management of radiation effects in the environment (International Commission on Radiological Protection 2007). The ICRP, therefore, introduced the concept of Reference Animals and Plants (RAPs) for a system of radiological environmental protection (International Commission on Radiological Protection 2008). The ICRP has published its aims covering:

  • prevention or reduction of the frequency of deleterious (harmful) radiation effects on biota (animals and plants) to a level where they would have a negligible impact on the maintenance of biological diversity
  • the conservation of species and the health and status of natural habitats, communities, and ecosystems (International Commission on Radiological Protection 2014). No dose limits are proposed to apply, but a set of derived consideration reference levels for representative species are recommended for use in assessing the impact of different sources of exposure

In the UK, the current legislative measures for protection of wildlife from radiation are implemented through The Conservation of Habitats and Species (Amendment) (EU Exit) Regulations 2019, known as the ‘Habitats Regulations’ (UK Statutory Instruments 2019).

Under the ‘Habitats Regulations’, the Environment Agency, NRW and SEPA are required to review existing authorisations or permits to ensure that no authorised activity or permission has an adverse effect, either directly or indirectly, on the integrity of Natura 2000[footnote 4] habitat sites. Similarly, for any new or varied authorisation or permit, whereby the applicant must assess the potential impact of the discharges on reference organisms that represent species which may be adversely affected.

The assessment of impacts on wildlife and plants (non-human) species is also considered during the determination of applications for new and varied environment permits. Further information concerning assessment of dose rates to reference organisms is available in earlier RIFE (for example, (Environment Agency and others 2017)) and Environment Agency reports (Environment Agency 2009a/b).

SEPA has carried out a pressures and impacts assessment from radioactive substances on Scotland’s water environment. The study concluded that there was no adverse impact on the aquatic environment as a result of authorised discharges of radioactive substances. However, it recognised that there may be a need for further data to support this conclusion. SEPA has included a specific habitats assessment in any new authorisation granted by the agency.

1.3. Sources of radiation exposure

1.3.1. Radioactive waste disposal from nuclear sites

The permits and authorisations (see Appendix 1) issued by the environment agencies to nuclear sites require operators to minimise the volume and activity of all forms of radioactive waste generated. They also limit any liquid or gaseous discharges and ensure that solid low-level waste (LLW) is sent to a suitable disposal site.

Solid LLW from nuclear sites may be transferred to the low level waste repository (LLWR) for a range of treatments or disposal. Solid wastes containing low quantities of radioactivity can also be disposed of at permitted solid waste disposal sites (see Section 7). Solid LLW from Dounreay, intended for disposal, can be transferred to the Dounreay LLW facility.

Figure 1.2 shows the nuclear sites, and their respective nuclear sectors, that produce waste containing artificial radionuclides, across the UK. Nuclear sites are permitted or authorised to dispose of radioactive waste and are also subject to the Nuclear Installations Act 1965 (United Kingdom - Parliament 1965). The monitoring programmes reported here cover all these sites.

In April 2024, Magnox Limited changed its name to Nuclear Restoration Services Limited (NRS) continuing its role as a wholly owned subsidiary of the Nuclear Decommissioning Authority (NDA).

Figure 1.2. Current nuclear sites in the UK, 2024. (Some operations are undergoing decommissioning).

Discharges of radioactive waste from non-nuclear sites such as hospitals, industrial sites and research establishments were also regulated under relevant legislation (EPR 16 in England and Wales, EASR18 in Scotland and still RSA 93 in Northern Ireland), but not subject to the Nuclear Installations Act. Occasionally, radioactivity is detected in the environment during monitoring programmes because of discharges from these sites. For example, iodine-131 discharged from hospitals is occasionally detected in river and marine samples. Some very low level solid radioactive wastes are disposed of from non-nuclear sites to approved solid waste treatment or disposal sites (for controlled burial, incineration, or other treatment or disposal methods). There is also a radiological impact due to historical discharges of radionuclides from non-nuclear industrial activity that also occur naturally in the environment. This includes radionuclides discharged from the former phosphate processing plant near Whitehaven, and so monitoring is carried out near this site.

Routine monitoring is not usually undertaken around non-nuclear sites. However, some limited monitoring programmes are undertaken in Cumbria, Lancashire and Northamptonshire (Section 7). In Scotland, SEPA carries out routine sampling in the Firth of Clyde and at solid waste disposal sites to assess the impact of the non-nuclear industry on the environment. Additionally, to ensure the doses from combined discharges to a sewer network are assessed properly, SEPA periodically undertakes intensive sampling at major sewage treatment plants to monitor the combined discharges from the non-nuclear industry.

Permitted or authorised discharges, disposals of radioactive wastes and solid waste transfers from nuclear establishments in 2024, are given in Appendix 1 (Table A1.1 to Table A1.4, inclusive). The tables also list the site discharge and disposal limits that are specified or, in the case of the Ministry of Defence (MOD), administratively agreed. In 2024, discharges and disposals were all below the limits. Solid waste transfers from nuclear establishments in Scotland are also given in Appendix 1 (Table A1.4). Section 7 gives information on discharges from non-nuclear sites.

The discharge limits are set through an assessment process, initiated either by the operator or the relevant environment agency. In support of the process, prospective assessments of doses to the public are made assuming discharges at the specified limits. Using this conservative assumption, discharge limits are set so that doses to the public will be below the source and site dose constraints of 0.3 and 0.5mSv per year, respectively (Environment Agency, Scottish Environment Protection Agency, and others 2012).

The determination of discharge limits considers a comprehensive range of pathways including the consumption of food. When determining the limits, the effect of the planned discharges on the environment and wildlife is taken into account. In addition, the regulations require BAT, under the Environmental Permitting (England and Wales) Regulations, to be used to ensure that discharges and their impact are minimised. The principles of best practicable means (BPM) continue to be applied in Scotland (Scottish Environment Protection Agency 2019b). The UK environment agencies consider that the terms BPM and best practicable environmental option are equivalent to the use of BAT (Scotland & Northern Ireland Forum for Environmental Research 2005; Scottish Environment Protection Agency 2019b).

The discharges and disposals made by sites do not normally fluctuate significantly. However, from time to time there may be unplanned events that cause unintended leakages, spillages or other emissions that are different to the normal or expected pattern of discharges. These events must be reported to the environment agencies and may lead to follow up action, including reactive monitoring by the site, the environment agencies, or the food standards agencies. Where monitoring took place because of these events, the results are presented and discussed in the relevant site text later in this report. Appendix 1 (Table A1.5) summarises the types of events that occurred in 2024.

1.3.2. International agreements and new build

This section gives information on the context of UK radioactive discharges as they relate to international agreements and the future building of new nuclear power stations.

1.3.2.1. International agreements

The UK is a contracting party to the Convention for the Protection of the Marine Environment of the North-East Atlantic (the ‘OSPAR Convention’).

This provides a framework for preventing and eliminating pollution in the north-east Atlantic, including the seas around the UK (OSPAR 2021a; OSPAR 2021b). The North-East Atlantic Environment Strategy (NEAES) 2030 includes a new strategic objective:

“OSPAR will prevent pollution by radioactive substances in order to safeguard human health and to protect the marine environment, with the ultimate aim of achieving and maintaining concentrations in the marine environment at near background values for naturally occurring radioactive substances and close to zero for human made radioactive substances.”

This strategic objective will be delivered through 4 operational objectives as described in (OSPAR 2021b; Environment Agency and others 2024). The outcomes of the 2020 Radioactive Substances Strategy (RSS) have been described in previous RIFE reports.

The importance of an integrated approach to stewardship of the marine environment has long been established in the UK. The reports ‘Safeguarding Our Seas’ (Department of Agriculture Environment and Rural Affairs, Scottish Executive & Welsh Assembly Government 2002) and ‘Charting Progress 2’ (Department for Environment Food & Rural Affairs 2010), provided an initial strategy and assessment on the state of the UK seas. Further information concerning other individual and fully integrated assessments is available in earlier RIFE reports (for example, (Environment Agency, Food Standards Agency, Food Standards Scotland, Natural Resources Wales and others 2018)).

In 2010, the Marine Strategy Regulations 2010 came into force. These Regulations require us to take action to achieve or maintain good environmental status (GES) in our seas (subject to certain exceptions) through the production of a “Marine Strategy” for all UK waters and that this is coordinated across the 4 UK Administrations. The UK Marine Strategy provides the framework for assessing and taking measures to achieve and maintain GES in our seas. It covers a wide range of biodiversity and marine environment descriptors including contaminants, and contaminants in seafood. Data in the RIFE report is used to support the UK Marine Strategy to demonstrate where GES has been achieved and maintained. More information on Descriptor 8 can be found at Marine online assessment tool - radionuclides.

The UK Marine Strategy is split into 3 parts:

  • part 1 - initial assessment of UK seas, first published in 2012, revised in 2019 to include an assessment towards achieving GES and revised targets or indicators. At time of writing, a public consultation is taking place on the 3rd update of the UK Marine Strategy. This closed on the 15 August 2025
  • part 2 - setting out the UK marine monitoring programmes, published in 2014 and 2021 (to take account of the revised part 1)
  • part 3 – programme of measures, published in 2015 and 2025

Further details on the UK Marine Strategy can be found on Marine online assessment tool.

1.3.3.2. Nuclear new build

In the 2008 white paper ‘Meeting the Energy Challenge’ (Department of Business Enterprise and Regulatory Reform 2008), the UK government set out its view that new nuclear power stations should have a role to play in this country’s future energy mix. More information about the basis of the white paper, subsequent national policy statements, consultations, and decisions, together with details of the approach for assessing potential new nuclear power station designs and approvals for their proposed developments, is available in earlier RIFE reports (for example, (Environment Agency, Food Standards Agency, Natural Resources Wales and others 2014)). The UK government has set out its current position on energy policy in the December 2020 white paper, ‘Powering our Net Zero Future’ (Department of Business Energy and Industrial Strategy (BEIS) 2020). In this white paper, the UK government highlights the need to address climate change urgently and includes a continuing and future role for nuclear generation to provide reliable clean electricity.

Currently, only 2 sites, Hinkley Point C and Sizewell C have received approval for power generation. The UK government re-affirmed its position on nuclear power generation as part of the 2022 British Energy Security Strategy, with an aim of generating up to 25% of the projected 2050 UK demand through deployment of civil nuclear (HM Government 2022). In March 2023 the government published its ‘Powering Up Britain’ documents that include its Energy Security Plan. This sets out the steps it is taking to ensure that the UK is more energy independent, secure and resilient. It confirms the aim to make final investment decisions on 2 new nuclear power stations in the next parliament (in other words by 2029). It also confirmed that government will develop a new Nuclear National Policy Statement. The documents are available on Powering up Britain. In January 2024, the UK government published its ‘Civil Nuclear: Roadmap to 2050’ (Department for Energy Security and Net Zero 2024), which sets the governments ambition for up to 24 Gigawatts of nuclear capacity, which would represent 25% of the country’s projected electricity demand. This would be delivered by Great British Nuclear through a combination of large-scale, small and advanced modular reactors.

As regulators of the nuclear industry, the ONR, the Environment Agency and NRW, are working together to ensure that any new nuclear power stations built in the UK meet high standards of safety, security, environmental protection, and waste management through the generic design assessment process (GDA). The steps undertaken by the regulators are described in previous RIFE reports (Environment Agency, Food Standards Agency and others 2021). As of December 2024, 3 small modular reactor designs are currently progressing through the GDA process. More information on the GDA process can be found here: Environment Agency assessing reactor designs and [ONR assessment of reactors]https://www.onr.org.uk/generic-design-assessment/assessment-of-reactors/.

NNB Generation Company (HPC) Limited is continuing the construction of a new twin UK European Pressurised Reactor™ (EPR™) nuclear power station at Hinkley Point C in Somerset. The ONR and Environment Agency continue to regulate both the construction and the development of the operating organisation. The Environment Agency regulates environmental matters at the site under construction related and operational permits. The development of NNB Generation Company (HPC) Limited is of interest to both regulators to ensure that the company has the competences and resources required to secure safety, security, and environment protection throughout construction and operation as it prepares itself to be an operator.

The ONR and the Environment Agency are continuing to work with Sizewell C Limited (previously NNB GenCo (SZC) Limited) that is seeking to construct a new nuclear power station at Sizewell C, Suffolk. The project replicates the Hinkley Point C station.

In 2020, the ONR and Environment Agency received applications from Sizewell C Limited for a nuclear site licence, and radioactive substances activities permit. In March 2023, the Environment Agency granted the radioactive substances permit to Sizewell C Limited following public consultation. In May 2024, the nuclear site licence was granted by the ONR.

1.3.3. Managing radioactive liabilities in the UK

The UK government has been managing radioactive waste for many decades in accordance with the Joint Convention on the Safety of Spent Fuel Management and on the Safety of Radioactive Waste Management (International Atomic Energy Agency 1997). This convention aims to ensure that individuals, society, and the environment are protected from the harmful effects of ionising radiation, from the management of spent nuclear fuel and radioactive waste. Further information relevant to the UK demonstrating compliance under the Joint Convention is available in earlier RIFE reports (for example, (Environment Agency, Food Standards Agency, Food Standards Scotland, Natural Resources Wales and others. 2019)). The most recent UK national report was presented at the 8th Review Meeting in March 2025 (Department for Energy Security & Net Zero 2024).

The NDA, a non-departmental public body, manages the decommissioning and clean-up of the civil public sector nuclear sites. The NDA reports to DESNZ and is responsible to Scottish ministers. The role of the NDA is strategic, developing and implementing an overall strategy for cleaning up the civil public sector nuclear legacy. The NDA’s strategic objective is to manage radioactive waste and dispose of it where possible, or place it in safe, secure, and suitable storage, in line with the UK and devolved administrations’ policies. The Energy Act 2004 (United Kingdom - Parliament 2004) requires the NDA to review and publish its strategy every 5 years. Its most recent strategy was published in 2021 (Nuclear Decommissioning Authority 2021) and the business plan for 2025 to 2028 is available (Nuclear Decommissioning Agency 2025). In 2022, the NDA published an inventory and forecast of radioactive wastes in the UK (as of 1 April 2022) jointly with DESNZ (Nuclear Decommissioning Agency & Department for Energy Security and Net Zero 2022a; Nuclear Decommissioning Agency & Department for Energy Security and Net Zero 2022b) and a Mission Progress Report in 2024 (Nuclear Decommissioning Agency 2024).

In 2007, the UK government and devolved administrations issued a UK-wide policy document, setting out principles for the long-term management of solid LLW (Department for Environment Food & Rural Affairs, Department of Trade and Industry & the Devolved Administrations 2007). Following the introduction of the LLW policy, the UK LLW Strategy was published in 2010 (Nuclear Decommissioning Authority 2010). A new UK LLW Strategy was published in 2016 (Department of Energy and Climate Change and others 2016). Some LLW, mostly from non-nuclear sites, and some very low-level radioactive waste is currently disposed of in solid waste disposal by controlled burial (Section 7). There is still a large amount of solid LLW that will require disposal. Some will be sent to the LLWR. The LLW from Dounreay can be disposed of at the new Dounreay LLW Facility close to the site.

In 2022, Nuclear Waste Services (NWS) was launched, which brings together the operator of the LLWR, Geological Disposal Facility (GDF) developer Radioactive Waste Management Limited and the NDA group’s integrated waste management programmes into a single organisation. NWS has assumed responsibility for the development of a GDF.

In 2023, DESNZ ran a consultation on proposals to update and consolidate the policies of the UK government and devolved administrations on the management of radioactive substances and nuclear decommissioning into a single UK-wide policy framework (Department for Energy Security and Net Zero 2023a; Department for Energy Security and Net Zero 2023b). This has been published in May 2024 (Department for Energy Security & Net Zero and others 2024). This has replaced the previous national policy on radioactive waste management (United Kingdom - Parliament 1995b).

The NDA is responsible for implementing UK and Welsh Government policies on the long-term management of higher activity radioactive waste (HAW) through geological disposal. Scottish Government policy is that the long-term management of HAW should be in near-surface facilities. Facilities should be located as near to the site where the waste is produced as possible. Guidance to site operators and regulatory position statements on the management of HAW on licensed sites has been issued by the Environment Agency, NRW, SEPA and the ONR (Environment Agency, Office for Nuclear Regulation and others 2021; Office for Nuclear Regulation and others 2021).

The UK government’s initial framework was set out in the 2008 (Department for Environment Food & Rural Affairs and others 2008), with updates in 2014 (Department of Energy and Climate Change 2014) and 2018 (Department of Business Energy and Industrial Strategy (BEIS) 2018a). This latter update also describes the positions of the devolved administrations: radioactive waste management is a devolved policy issue. Therefore, the Scottish Government, Welsh Government and Northern Ireland Executive each have responsibility for determining disposal policy in their respective areas. Further information on the aspects of GDF is available on the GOV.UK website:geological disposal facility for high activity waste and GDF (Geological Disposal Facility) - GOV.UK.

The Committee on Radioactive Waste Management (CoRWM) continues to provide independent scrutiny of the government’s long-term management, storage, and disposal of radioactive waste. This committee has published its annual report for 2024 (Committee on Radioactive Waste Management 2025a), proposed work programme for 2024 (Committee on Radioactive Waste Management 2025b) and a position paper on the UK’s progress towards the delivery of an operational GDF (Committee on Radioactive Waste Management 2025c).

Guidance on requirements for authorisation for geological and near-surface disposal facilities has been published (Environment Agency, Northern Ireland Environment Agency & Scottish Environment Protection Agency 2009; Environment Agency & Northern Ireland Environment Agency 2009; Environment Agency 2012a). SEPA has issued a policy statement on how it will regulate the disposal of LLW from nuclear sites (Scottish Environment Protection Agency 2012) and published joint guidance with the Environment Agency and NRW on the surrender of nuclear site permits that include how potential onsite disposals of radioactive waste should be considered by site operators (Scottish Environment Protection Agency, Environment Agency & Natural Resources Wales 2018). In May 2019, SEPA issued guidance on the decommissioning of non-nuclear facilities (for example, a single laboratory) from radioactive use (Scottish Environment Protection Agency 2020).

Decommissioning of many nuclear sites in Great Britain is currently underway. Following the Environment Agencies’ consultation on the draft guidance, ‘Guidance on Requirements for Release of Nuclear Sites from Radioactive Substances Regulation’, referred to as ‘GRR’ was published in 2018 (Scottish Environment Protection Agency and others 2018). This guidance describes what operators must do to release sites from radioactive substances regulation and is also available via:decommisioning of nuclear sites and release from regulation.

Naturally occurring radionuclides are enhanced in some wastes (Naturally Occurring Radioactive Material (NORM)), and those wastes are subject to existing regulatory systems that are designed to protect human health and the environment. Further information relevant to the UK NORM Waste Strategy, published in 2014, is available in earlier RIFE reports (for example, (Environment Agency, Food Standards Agency, Food Standards Scotland, Natural Resources Wales and others 2018)).

1.3.4. Solid radioactive waste disposal at sea

In the past, packaged solid waste of low radioactivity concentrations was disposed of deep in the North Atlantic Ocean, the last disposal of this type was in 1982. The UK government announced at the OSPAR Ministerial meeting in 1998 that it was stopping disposal of this material at sea. At that meeting, Contracting Parties agreed that there would no longer be any exception to prohibiting the dumping of radioactive substances, including waste (OSPAR 1998). The environmental impact of the deep ocean disposals was assessed by detailed mathematical modelling and has been shown to be negligible (Organisation for Economic Co-operation and Development Nuclear Energy Agency 1985). Disposals of small amounts of waste also took place from 1950 to 1963 in a part of the English Channel known as the Hurd Deep. The results of environmental monitoring of this area are presented in Section 8 and confirms that the radiological impact of these disposals was insignificant.

In England, the Marine Management Organisation administers a range of statutory controls that apply to marine works on behalf of the Secretary of State for Environment, Food and Rural Affairs. This includes issuing licences under the Marine and Coastal Access Act 2009 (United Kingdom - Parliament 2009) for the disposal of dredged material at sea. In Northern Ireland, Scotland and Wales, licences for disposal of dredged material at sea are the responsibility of Department of Agriculture, Environment and Rural Affairs (DAERA), the Scottish Government (Marine Scotland) and NRW, respectively.

The protection of the marine environment is considered before a licence is issued. Since dredged materials will contain varying concentrations of radioactivity from natural and artificial sources, assessments are carried out, when appropriate, to provide reassurance that there is no significant risk to the food chain or other risk from the disposal. Guidance on exemption criteria for radioactivity in relation to sea disposal is available (International Atomic Energy Agency 1999). The International Atomic Energy Agency (IAEA) has published a system of assessment that can be applied to dredged spoil disposal (International Atomic Energy Agency 2003; International Atomic Energy Agency 2015) and which has been adapted to reflect operational practices in England and Wales (McCubbin & Vivian 2006). In 2023, no new requests were received to apply for additional licences for the disposal of dredged material (containing radioactivity) at sea.

1.3.5. Other sources of radioactivity

There are several other anthropogenic sources of radioactivity that may affect the food chain and the environment. These could include disposals of material from offshore installations, transport incidents, satellite re-entry, releases from overseas nuclear installations and the operation of nuclear-powered submarines. UKHSA has assessed incidents involving the transport of radioactive materials in the UK (Jones & Harvey 2014). UKHSA have also considered the effects of discharges into the marine environment from the oil and gas industry, with the estimated highest individual dose (per head of population) being less than 0.001mSv per year (Harvey, Smith & Cabianca 2010).

Submarine berths in the UK are monitored by the MOD (for example, (Defence Science and technology Laboratory 2024)). General monitoring of the British Isles is carried out as part of the programmes described in this report, to detect any significant effects from the sources above. No such effects were found in 2024. Low concentrations of radionuclides were detected in the marine environment around the Channel Islands (Section 8), and these may be partly due to discharges from the nuclear fuel reprocessing plant at La Hague in France.

The exploration for, and extraction of, gas from shale rock has been investigated in the UK with support from DESNZ. Further details on fracking: developing shale gas in the UK are provided on the GOV.UK website:about shale gas and hydraulic fracturing (fracking).

Further information on the previous involvement by each of the environment agencies to support engagement with industry, and other related issues to shale gas extraction, is available in earlier RIFE reports (for example, RIFE 29).

The Environmental Protection Act 1990 provides the basis for a regulatory regime for identifying and remediating contaminated land. In the UK, there is a duty to inspect land under Part II A of the Environmental Protection Act 1990, but there must be reasonable grounds for inspecting land for radioactivity. Reasonable grounds are defined in the statutory guidance. Once it is decided that an area is a special site, it is regulated by the environment agencies in their respective areas.

In England and Wales, regulations were extended in 2007 to cover land contaminated with radioactivity originating from nuclear sites. DESNZ issued revised guidance for radioactive contaminated land to local authorities and the Environment Agency in 2012 (Department of Energy and Climate Change 2012). The Environment Agency has issued a series of briefing notes that provide information on land contaminated with radioactivity in England and Wales (Environment Agency 2012b). In 2018, DESNZ carried out a targeted consultation process on proposed updates to the statutory guidance for radioactive contaminated land on behalf of the UK and Welsh Governments.

Updates have subsequently been made to the statutory guidance for England, which was published in 2018 (Department of Business Energy and Industrial Strategy (BEIS) 2018b). Clear dose criteria are set for homogeneous and heterogeneous contamination. Also, the risk (probability or frequency of occurrence) of receiving the dose should be considered for the designation of radioactive contaminated land. To date, no site has been legally designated as ‘radioactive contaminated land’ due to radioactivity in England and Wales.

Equivalent legislation for identifying and remediating contaminated land comprising The Radioactive Contaminated Land Regulations (Northern Ireland) 2006 and subsequent amending legislation, issued in 2007 and 2010, exists as Statutory Instruments in Northern Ireland (Statutory Instruments 2007; Statutory Instruments 2010).

In 2007, the Radioactive Contaminated Land (Scotland) Regulations came into force by amending Part II A of the Environmental Protection Act 1990. SEPA has powers to inspect land that may be contaminated with radioactivity, to decide if land should be identified as radioactive contaminated land and require remediation if considered necessary. Revised Statutory Guidance was issued to SEPA in 2009. This guidance is broadly similar to that issued to the Environment Agency. In Scotland, clear dose criteria are set for homogeneous and heterogeneous contamination. Also, the risk (probability or frequency of occurrence) of receiving the dose should be considered for the designation of radioactive contaminated land. To date, no site has been designated as ‘contaminated land’ due to radioactivity in Scotland.

The contribution of aerial radioactive discharges from UK installations to concentrations of radionuclides in the marine environment has been studied (Department for Environment Food & Rural Affairs 2004). The main conclusion was that aerial discharges do not make a significant contribution to activity concentrations in the marine environment. On occasion, the effects of aerial discharges may be detected in the aquatic environment, and conversely the effects of aquatic discharges may be detected on land. Where this is found, appropriate comments are made in this report.

All sources of ionising radiation exposure to the UK population are reviewed by UKHSA, the most recent report was published in June 2025. Available from: UKHSA radiation and you. The most significant source of exposure was from natural radiation (radon and thoron gases). Figure 1.3 provides a breakdown of the exposure to the UK population by source.

Figure 1.3. Average UK population exposure from natural and artificial sources of radioactivity (UKHSA radiation and you)
Category Percentage of total exposure from natural and artificial sources of radioactivity
radon and thoron in the home (from naturally occurring sources) 44
diagnostic medical procedures 16
terrestrial gamma radiation 14
cosmic radiation (non-occupational) 13
intake of naturally occurring radionuclides, excluding radon 10
occupational exposure to natural sources 4.0
other sources 0.3

The average individual dose from exposure to all significant sources of ionising radiation was estimated to be about 2.6mSv per year, the same as that reported in the previous reviews (Watson and others 2005; Oatway and others 2016). The dose from radiation in the environment was about 84% or 2.2 mSv per year of the dose from all sources of radiation. This was dominated by exposure to naturally occurring sources of radiation although there is significant variation across the UK due to local geology and other factors. Only about 0.3% of the annual dose was from artificial sources. Of this, the majority was from radionuclides released during historical testing of nuclear weapons in the atmosphere (global fallout) from the 1950s and 1960s (hereafter referred to as ‘nuclear weapons testing’). Exposure to radionuclides routinely discharged by industry contributing less than 0.01% to the total dose.

2. Methods of sampling, measurement and presentation used in this report

This section explains the scope of the monitoring programmes presented in this report (hereafter referred to as ‘programmes’) and summarises the methods and data used to measure and assess radioactivity in food and the environment. The bulk of the programmes, assessment methods and data have continued in 2024 unchanged, however, the main changes are:

Sampling and measurement

  • special sampling at nuclear sites – if judged necessary, this was continued where there were unusual short-term increases in discharges and inadvertent releases

Assessment and presentation

  • site maps - maps of sites and sampling locations have been revised and updated
  • new habits data - consumption and occupancy rates have been updated with the benefit of recent habits survey results at the Hartlepool, Hinkley Point and Sellafield in England, Hunterston and along the Dumfries and Galloway coast in Scotland

Accompanying this report is a further set of files giving full details of each assessment of ‘total dose’ summed over all sources at each site. These are available on the main RIFE page.

The appendices of this report contain further details on:

  • modelling to extend or improve the results of monitoring (Appendix 3)
  • consumption, occupancy and other habits data (Appendix 4)
  • dosimetric data (Appendix 5)
  • estimates of concentrations of natural radionuclides (Appendix 6)

Guidance on planning and implementing routine environmental radiological monitoring programmes has been published Environment Agency radiological monitoring guidance and (Scottish Environment Protection Agency 2019a). In recent years, the Environment Agency (with NRW providing advice on monitoring in Wales), FSA, FSS and SEPA have all completed reviews of their environmental radioactivity monitoring programmes. Further information is available in earlier RIFE reports and in Section 1.1.

2.1. Sampling programmes

The primary purpose of the programmes is to check on the quantities of radioactivity in food and the environment. Results are used to demonstrate that the safety of the public is not compromised and that doses, resulting from discharges of radioactivity, are below the statutory dose limits (see Section 1 for more details). The scope in 2024 extends throughout the UK (and the Channel Islands) and is undertaken independently of the industries which discharge wastes to the environment. Samples of food, water and other materials are collected from the environment and analysed in specialist laboratories. In situ measurements of radiation dose rates and contamination are also made and the results of the programmes are assessed in terms of limits and trends in this report. Subsidiary objectives for the programmes are:

  • to provide information to assess the impact on non-human species
  • to enable indirect confirmation of compliance with authorised or permitted waste disposals
  • to determine whether undisclosed releases of radioactivity have occurred from sites
  • to establish a baseline to judge the importance of accidental releases of radioactivity should they occur
  • to demonstrate compliance with international obligations, such as The Oslo and Paris Convention for the Protection of the marine environment of the North-East Atlantic (OSPAR)

Routine sampling is focused on nuclear sites licensed under the Nuclear Installations Act, 1965 (United Kingdom - Parliament 1965). The programmes also serve to provide information to assist the environment agencies to fulfil statutory duties, which are further described in Section 1.1. Additional sampling is conducted in areas remote from nuclear sites to establish the general safety of the food chain, sources of drinking water and the environment. Results from this sampling generate data that are used as ‘background’ activity concentrations to compare with results from around nuclear sites and to show the variation in the quantities of radioactivity across the UK. Quantities of radioactivity in the environment can also be affected by disposals of radioactive waste from nuclear sites abroad and show the legacy of atmospheric fallout from both past nuclear weapons testing and the nuclear reactor accidents (such as at Chernobyl in Ukraine in 1986).

Various methods for undertaking sampling and analysis are available. The programmes are primarily directed at relatively widespread radiological contamination where the likelihood of encounter or consumption is certain. Where a source of potential exposure to particles of radioactivity is concerned, the likelihood of encounter is an important factor. This is considered separately in this report in site specific programmes targeted at contamination from radioactive particles.

The programmes can be divided into 3 main sectors, generally based on the source of radioactivity in the environment:

  • nuclear sites discharging gaseous and liquid radioactive wastes
  • selected non-nuclear sites and solid waste disposal sites
  • UK regional monitoring and overseas accidents

2.1.1. Nuclear sites

Nuclear sites are the prime focus of the programmes as they have been responsible for the largest individual discharges of radioactive waste. Sampling and direct monitoring is conducted close to most of the sites shown in Figure 1.2 (except those which have a very low effect). At Sellafield, radionuclides from liquid discharges can be detected in the marine environment in many parts of north-European waters. Therefore, programmes for this site extend beyond national boundaries.

The frequency and type of measurement and the materials sampled vary from site to site and are chosen to be representative of existing exposure pathways. Information on local peoples’ diets and way of life, from habits surveys, are used to inform the exposure pathways. Consequently, the programme may vary from site to site and from year to year. Detailed information on the scope of the programme at individual sites is given in the tables of results. The routine programme is supplemented by additional monitoring if applicable, for example, in response to incidents or reports of unusual or high discharges of radioactivity with the potential to enter the food chain or the environment. Results of both routine and additional monitoring are included in this report.

The main aim of the programme is to monitor the environment and diet of people who live or work near nuclear sites, to estimate doses for those small groups of people who are most at risk from discharges of radioactive waste. It is assumed that if the most exposed people have a dose below the national and international legal limit then all others should receive an even lower dose. For liquid wastes, the pathways that are the most relevant to discharges are the ingestion of seafood and freshwater fish, drinking water and external exposure from contaminated materials. For gaseous wastes, the effects are due to the ingestion of terrestrial foods, inhalation of airborne activity and external exposure from material in the air and deposited on the ground. Inhalation of airborne activity and external exposure from airborne material and surface deposition are difficult to assess by direct measurement but can be assessed using environmental models. The main part of the monitoring is therefore directed at a variety of foodstuffs and measurements of external dose rates on the shores of seas, rivers and lakes. The programme also includes some important environmental indicators, so that quantities of radioactivity can be put in a historical context.

2.1.2. Selected non-nuclear site and solid waste disposal sites

Although the emphasis of the monitoring programme is the nuclear industry, a small proportion of the monitoring programmes are focussed on other activities that may have a radiological impact on people and the food chain. This part of the programme considers the effect of disposals of naturally occurring and artificial radionuclides from non-nuclear industries and of disposal into solid waste disposal sites, other than at Dounreay (considered separately in Section 5).

The impact of the non-nuclear industry was studied at several locations in 2024 including East Northants Resource Management Facility (near Kings Cliffe), the River Clyde (Glasgow) and Whitehaven (see Section 7). As in recent years, a small-scale programme was undertaken near Hartlepool (see Section 4.1.4), in addition to that directed at the effects of the power station itself. Sampling and analysis reflected the nature of the sources (of radioactivity) under study and, where appropriate, included consideration of the enhanced concentrations of naturally occurring radionuclides from non-nuclear industrial activity. There are also occasional specific programmes that consider, for example, the effects of land contaminated with historical sources of radioactivity and discharges from non-nuclear sites such as hospitals.

The distribution of solid waste disposal sites considered in 2024 is shown in Figure 7.1. Sites were studied to assess the extent of radiological contamination, if any, leaching from the site and re-entering the terrestrial environment (as leachates collected in surface waters close to the sites).

2.1.3. UK regional monitoring and fallout in the UK from overseas accidents

The programme of regional monitoring considers the quantities of radioactivity in the environment in areas away from specific sources as an indication of general radiological contamination of the food supply and the environment. The component parts of this programme are:

  • monitoring of the Channel Islands and Northern Ireland
  • dietary surveys
  • sampling of milk
  • drinking water sources, groundwater, rain and airborne particulates
  • seawater surveys
  • fallout in the UK from overseas accidents
Channel Islands and Northern Ireland

The programmes for the Channel Islands and Northern Ireland are designed to complement that for the rest of the UK and to take into account the possibility of long-range transport of radionuclides.

Channel Islands monitoring is conducted on behalf of the Channel Island States. It consists of sampling and analysis of seafood and indicator materials as a measure of the potential effects of UK and French disposals into the English Channel and historical disposal of solid waste in the Hurd Deep.

Monitoring on the Isle of Man for foodstuffs and indicator materials ceased in 2013 and 2016 (Environment Agency and others 2015; Environment Agency, Food Standards Agency, Food Standards Scotland and others 2016) , respectively. Monitoring of the marine environment is primarily directed at the effects of current and historical disposals from Sellafield.

The Northern Ireland programme is directed at the far-field effects of disposals of liquid radioactive wastes into the Irish Sea. Seafood and indicator materials are collected from a range of coastal locations including marine loughs, and dose rates are monitored on beaches.

General diet

The purpose of the general diet survey programme is to provide information on radionuclides in the food supply to the wider population, rather than to those living near particular sources of radiological contamination such as the nuclear industry. This programme is based on sampling and analysis of canteen meals throughout the UK. It provides background information that is useful in interpreting site-related measurements and helps ensure that all significant sources of radiological contamination form part of the site-related programme.

Specific foods, freshwater, rain and airborne particulates

Further background information on the relative concentrations of radionuclides is gained from the sampling and analysis of milk. Freshwater, rain and airborne particulates are also analysed to add to the understanding of radionuclide intakes by the population via ingestion and inhalation and as general indicators of the state of the environment.

Milk sampling took place at dairies throughout the UK in 2024.

Meat and crop monitoring of naturally occurring and artificial radionuclides, as a check on general food contamination, remote from nuclear sites, ceased in 2014. However, in 2024, surveillance of imported food at ports of entry using radiation screening equipment continued as a means of detecting the effects of overseas incidents. If screening and subsequent sample analysis shows quantities of radioactivity that fail to comply with UK food standards, which are retained from EU directives or regulations, then the consignments are removed from the UK market.

Freshwater used for the supply of drinking water was sampled throughout England, Northern Ireland, Scotland and Wales. Regular measurements of radioactivity in air and rainwater were also made.

Seawater surveys

Seawater surveys are conducted in the seas around the UK on behalf of the DESNZ to provide information on radionuclide concentrations and information on water transport mechanisms in the coastal seas of northern Europe. Such information is used to support international studies of the health of the seas under the auspices of the OSPAR Conventions (OSPAR 2000), to which the UK is a signatory and in support of research on the fate of radionuclides discharged to sea. These surveys are conducted using government research vessels and are supplemented by a programme of spot sampling of seawater at coastal locations.

Fallout in the UK from overseas accidents

Monitoring of the long-range effects of the Fukushima Dai-ichi accident started across the UK in March 2011. Samples from all sectors of the environment were taken and analysed by gamma spectrometry. The most significant radionuclides to monitor were iodine-131 and caesium-137, which were prevalent in the release from the accident. Very low activity concentrations were detected, and the extended programme ceased later in 2011. Further details of the programme and the results are given in the RIFE report for 2011 (Environment Agency, Food Standards Agency and others 2012).

Monitoring of the effects of the 1986 Chernobyl accident was undertaken in relation to the upland contamination of lakes. Earlier RIFE reports have provided detailed results of monitoring by the environment agencies and FSA (Environment Agency and others 2013). Sheep monitoring ceased in 2012 due to the removal of restrictions on the movement, sale and slaughter of sheep in parts of Cumbria and North Wales. Sampling for freshwater fish in locations affected by Chernobyl ceased in 2014.

2.2 Methods of measurement

There are 2 basic types of measurement made:

  • dose rates are measured directly in the environment
  • samples collected from the environment are analysed for their radionuclide content in a laboratory

2.2.1. Sample analysis

Analysis of samples varies depending on the nature of the radionuclide under investigation. The types of analysis can be broadly categorised into 2 groups:

  • gamma-ray spectrometry
  • radiochemical methods

The former is a cost-effective method of detecting a wide range of (gamma-emitting) radionuclides, commonly found in radioactive wastes, and is used for most samples. Radiochemical methods consist of a range of analyses involving the application of chemical separation and purification techniques to quantify the concentrations of alpha- and beta-emitting radionuclides. These are sensitive determinations, but generally more labour intensive. These methods are only used if alpha and beta concentration data are required for specific radionuclides and are not detectable using gamma-ray spectrometry (see Section 2.4 for discussion on limits of detection).

Several laboratories analysed samples in the monitoring programmes described in this report. Their main responsibilities were as follows:

Cefas

Centre for Environment, Fisheries and Aquaculture Science, gamma-ray spectrometry and radiochemical analysis of food samples in England, Wales, Northern Ireland and the Channel Islands

SOCOTEC

SOCOTEC UK Limited, gamma-ray spectrometry and radiochemical analysis of environmental samples (including analysis of sources of drinking water) in England and Wales

UKHSA

UK Health Security Agency, gamma-ray spectrometry and radiochemical analysis of food and environmental samples from Scotland, air and rain samples in England, Wales and Northern Ireland, and freshwater for Northern Ireland

Each laboratory operates quality control procedures to the standards required by the UK environment and food standards agencies and have their analytical procedures independently assessed by the UK Accreditation Service. This ensures the requirements from the international standard ISO 17025 (International Organisation for Standardisation 2017) are maintained. Regular calibration of detectors is undertaken and intercomparison exercises are held with participating laboratories. The quality assurance procedures and data are made available to the UK environment agencies, FSA and FSS for auditing. The methods of measurement include alpha and gamma-ray spectrometry; beta and Cerenkov scintillation counting; and alpha and beta counting using proportional detectors.

Corrections are made for the radioactive decay of short-lived radionuclides between the time of sample collection and measurement in the laboratory. This is particularly important for sulphur-35 and iodine-131. If a sample is bulked from a sequence of samples over time, the date of collection of the bulked sample is assumed to be in the middle of the bulking period. Otherwise, the actual collection date for the sample is used. In a few cases where short-lived radionuclides are part of a radioactive decay chain, the additional activity (‘in-growth’ and equilibrium status) produced from radioactive decay of parent and daughter radionuclides after sample collection is also considered. Where necessary, corrections to the activity present at the time of measurement are made to take account for 2 radionuclides, protactinium-233 and thorium-234.

The analysis of foodstuffs is conducted on that part of the sampled material that is normally eaten, for example, shells of shellfish and the pods of some legumes are discharged before analysis. Most other foodstuffs are analysed raw, as it is conceivable that all the activity could be consumed in the raw foodstuff. Some shellfish samples are cooked (boiled) to represent processing by members of the public and therefore, some activity will be lost as a consequence. Several studies have investigated the loss of activity of caesium-137, strontium-90 and polonium-210, which are dependent upon cooking method (International Atomic Energy Agency 1992; International Atomic Energy Agency 2009; Uddin and others 2019; Abd-Elghany and others 2020; Johansen and others 2023). The retention factors for caesium-137 in fish after frying, baking or grilling ranged from 0.2 to 1.05 (Rantavaara 1989; International Atomic Energy Agency 2009; Nabeshi and others 2013) and 0.20 to 0.90 when steamed or boiled (Saiki 1994; International Atomic Energy Agency 2009). Similarity for bivalve molluscs the retention factors varied from 0.49 to 1.30 (Masson and others 1989; International Atomic Energy Agency 1992). The retention factor for strontium-90 in (boiled) fish was 0.90 (International Atomic Energy Agency 2009). The Uddin (Uddin and others 2019) and Johansen (Johansen and others 2023) studies suggest lower retention factors when samples are boiled or steamed, rather than grilled or fried, with polonium-210 retention factors of 0.58 and 0.56 for crustacean and bivalve molluscs, respectively (Johansen and others 2023). The depuration of plutonium-239+240, americium-241 and curium-243+244 from edible winkles has been studied by Swift (Swift 1995). The biological half-life for the initial elimination was less than 2 days and accounted for 70 to 90% of the activity within the winkles when collected.

2.2.2. Measurement of dose rates and contamination

Measurements of gamma dose in air over intertidal and other areas are normally made at 1 metre above the ground using RadEye SX Survey Meters or Mini Instruments[footnote 5] environmental radiation meters type 6-80, with both type of meters connected to compensated Geiger-Muller tubes, type MC-71. In some scenarios, for example, for people living on houseboats or for wildfowlers lying on the ground, measurements at other distances from the ground may be made. External beta doses are measured on contact with the source, for example fishing nets, using Mini Instruments[footnote 5], Smart ION and Electra PB19RD monitors. These portable instruments are calibrated against recognised reference standards, and the inherent instrument background is subtracted. There are 2 quantities that can be presented as measures of external gamma dose rate, total gamma dose rate or terrestrial gamma dose rate. Total gamma dose rate includes all sources external to the measuring instrument. Terrestrial gamma dose rate excludes cosmic sources of radiation but includes all others. In this report, the total gamma dose rate is presented. UKHSA reports terrestrial gamma dose rates to SEPA. Terrestrial gamma dose rate is converted to total gamma dose rate by the addition of 0.037µGy h,-1 which approximates the contribution made by cosmic radiation (Her Majesty’s Inspectorate of Pollution 1995).

Gamma monitoring of radiological contamination on beaches is undertaken, on behalf of SEPA, using similar instrumentation to that for measurements of dose rates. The aim is to cover a large area including strandlines where radioactive debris may become deposited. At Dalgety Bay (Section 7.7) and Dounreay (Section 5.1), in Scotland, and at Sellafield (Section 3.3.3), in Cumbria, special monitoring procedures are in place due to the potential presence of radioactive particles on beaches. Further information regarding Dalgety Bay, Dounreay, and Sellafield is provided elsewhere in this report.

2.3. Presentation of results

The tables of monitoring results contain summarised values of observations obtained during the year under review. The data are generally rounded to 2 significant figures. Values near to the limits of detection will not have the precision implied by using 2 significant figures. Observations at a given location, for activity concentrations and dose rates, may vary throughout the year. This variability may be due to changes in rates of discharge, different environmental conditions and uncertainties arising from the methods of sampling and analysis.

The method of presentation of the summarised results allows the data to be interpreted in terms of public radiation exposures for comparison with agreed safety standards.

For milk samples, the most appropriate quantity for use in assessments is the arithmetic mean in the year sampled from the farm with the highest mean activity concentration. This is labelled ‘max’ in the tables of results to distinguish it from the values that are averaged over a range of farms. For other terrestrial foods, an alternative approach is adopted since it is recognised that the possible storage of foods harvested during a particular time of the year has to be taken into account. Greater public exposures would be observed coincidentally with foods being harvested at times of elevated radiological contamination. For such foods, as well as the mean value, the maximum activity concentration (labelled ‘max’ in the tables) observed for each radionuclide is presented at any time in the relevant year and forms the basis for the assessment of dose.

Results are presented, where a sample is taken or a measurement is made, for each location or source of supply. Sample collectors are instructed to obtain samples from the same location during the year. Spatial averaging is therefore not generally undertaken, though it is inherent in the nature of some collected samples. A fish may move some tens of kilometres in an environment of changing concentrations in seawater, sediments and lower trophic levels. The resulting quantity of radiological contamination therefore represents an average over a large area. Similarly, cows providing milk at a farm may feed on grass and other fodder collected over a distance of a few kilometres of the farm. In the case of dose rate measurements, the position where the measurement is conducted is within a few metres of other measurements made within a year. Each observation consists of the mean of many instrument readings at a given location.

The numbers of farms that were sampled to provide information on activities in milk at nuclear sites are indicated in the tables of results. Milk samples collected weekly or monthly are generally bulked to provide quarterly samples for analysis each year. Otherwise, the number of sampling observations in the tables of concentrations refers to the number of samples that were prepared for analysis during the year. In the case of small animals such as molluscs, one sample may include several hundred individual animals.

The number of sampling observations does not necessarily indicate the number of individual analyses conducted for a specific radionuclide. In particular, determinations by radiochemical methods are sometimes conducted less frequently than those by gamma-ray spectrometry. However, results are often based on bulking of samples such that the resulting determination remains representative.

Only results that are the most relevant for assessing the impact of radionuclide concentrations in food and the environment are provided in each site table. This ensures that reporting of the more meaningful results is manageable. For example, gamma-ray spectrometry can provide many less than values and may not be reported. To identify the most relevant values, to be included in each individual table, one or more of the following conditions is required:

  1. All radionuclide results (both positively detected and less than values) are reported in the site table if the radionuclide is specified in the relevant permit or authorisation (as indicated for each site in Appendix 1, Table A1.1 and Table A1.2).

  2. All radionuclide results (both positively detected and less than values) are reported that have been analysed using a radiochemistry method (for example, plutonium radionuclides).

  3. For any radionuclide that is reported as positively detected in the previous 5 years of annual reporting, all activity concentration data of that radionuclide are reported (they are only excluded from the table after 5 continuous years of reporting ‘less than values’).

  4. For any radionuclide that is reported as positively detected in one of the samples, all activity concentration data of that radionuclide are reported for other samples presented in the table (terrestrial and marine) in that year.

  5. Naturally occurring radionuclides measured by gamma-ray spectrometry (for example potassium-40) are not usually reported unless the intention is to establish whether there is any enhancement above the expected background concentrations (for example from landfill sites).

2.4. Detection limits

There are 2 main types of results presented in the tables:

  • positively detected values
  • values preceded by a ‘less than’ symbol (<)

Where the results are an average of more than one value, and each value is positive, the result is positive.

Alternatively, where there is a mixture of data, or all data is at the limit of detection (LoD) or minimum reporting level, the result is preceded by a ‘less than’ symbol. Gamma-ray spectrometry can provide many ‘less than’ results.

Limits of detection are governed by various factors relating to the measurement method used and these are described in earlier reports (Ministry of Agriculture Fisheries and Food 1995). There are also a few results quoted as ‘not detected’ (ND) by the methods used. This refers to the analysts’ judgement that there is insufficient evidence to determine whether the radionuclide is present or absent.

2.5. Additional information

The main aim of this report is to present all the results of routine monitoring from the programmes described previously. However, it is necessary to carry out some averaging for clarity and to exclude some basic data that may be of use only to those with specific research interests. Full details of the additional data are available from the environment agencies and FSA. Provisional results of concentrations of radionuclides in food samples collected in the vicinity of nuclear sites in England, Northern Ireland (milk and canteen meals) and Wales are published on the (FSA’s data portal - radiological monitoring).

The main categories of additional data are:

  • data for individual samples prior to averaging
  • uncertainties in measurements
  • data for very short-lived radionuclides supported by longer-lived parents
  • data which are not relevant to a site’s discharges for naturally occurring radionuclides and for artificial radionuclides below detection limits
  • measurements conducted as part of the research programme described in Appendix 7

Very short-lived radionuclides such as yttrium-90, rhodium-103m, rhodium-106m, barium-137m and protactinium-234m (formed by decay of strontium-90, ruthenium-103, ruthenium-106, caesium-137 and thorium-234, respectively) are taken into account for calculating exposures to members of the public. They are not listed in the tables of results. As a first approximation, their concentrations can be taken to be the same as those of their respective parents.

2.6. Radiation protection standards

The monitoring results in this report are interpreted in terms of radiation exposures of the public, commonly termed ‘doses’. This section describes the dose standards that apply in ensuring protection of the public. Previous UK practice is described in previous RIFE reports.

The ICRP issued its latest recommendations for a system of radiological protection in 2007 as set out in ICRP Publication 103 (International Commission on Radiological Protection 2007). UKHSA have provided advice on the application of the ICRP 2007 recommendations to the UK (Health Protection Agency 2009). Overall, these consider that the new recommendations do not imply any major changes to the system of protection applied in the UK. In particular, for authorised or permitted releases, limits for effective and skin doses remain unchanged. Dose coefficients are also unchanged until such a time as new values are available and receive legislative endorsement.

The EU has updated the BSS Directive to account for the changes in ICRP recommendations (European Commission 2014). The revised directive, 2013/59/Euratom, was published in 2013 and arrangements for transposition of the Directive into UK law are complete, as described in Section 1.1. Further changes in UK radiological protection law and standards will be taken into account for future issues of this RIFE report.

The mean annual dose received by the ‘representative person’ is compared with the relevant dose limit. The term ‘representative person’ refers to those people most exposed to radiation. In this report, they are usually members of the public consuming large quantities of locally harvested food (high-rate consumers) or spending long periods of time in locations being assessed for external exposure. The dose limits apply to all age groups. Doses received by an individual will be age dependent because of differences in their physiology, anatomy and dietary habits. The embryo or foetus (prenatal child) can also receive higher doses than its mother. Consequently, doses have been assessed for different age groups; for example, adults, children (10-year-old), infants (1-year-old) and prenatal children, and from this information it is possible to determine which of these age groups receives the highest dose.

For drinking water, water quality regulations (Scottish Statutory Instruments 2015; Statutory Instruments 2016; Statutory Rules of Northern Ireland 2017; Welsh Statutory Instruments 2018), prescribe the requirements on the quality of water intended for human consumption in respect of radioactive substances and is retained from the 2013 EU Directive (European Commission 2013). These regulations specify values for gross alpha, gross beta, radon, tritium and ‘Indicative Dose’. Above these values, UK regulatory bodies shall assess whether the presence of radioactive substances in drinking water poses a risk to human health that requires action and, where necessary, take remedial action to improve the quality of water to a level which complies with the requirement for the protection of human health from a radiation protection point of view. Drinking water is taken to include bottled waters (spring and drinking).

In situations that present a novel exposure pathway for members of the public, ‘potential’ exposure routes and standards are determined, and these are discussed further in relation to particles of radioactivity (Dale, Robertson & Toner 2008). For contamination, known to be due to radioactive particles in the UK, a site-specific assessment is considered in the relevant section of this report.

Accidental releases will be assessed against UK and ICRP standards in emergency situations (Commission of the European Community 1987; International Commission on Radiological Protection 2007). In addition, it is government policy that food intervention levels retained from EU standards will be taken into account for setting discharge limits. Guidelines for radionuclides in foods following accidental radiological contamination for use in international trade has been published by the Codex Alimentarius Commission (Committee on Interagency Research and Policy Coordination Alimentarius Commission 2011).

2.7. Assessment methods

Calculations of exposures to members of the public in this report are primarily based on the environmental monitoring data for the year shown under study. The methods used have been assessed for conformity with the principles endorsed by the UK National Dose Assessment Working Group (Allott 2005), and were found to be compatible (Camplin & Jenkinson 2007). There are 2 types of dose assessment made. The first type gives an estimate of the ‘total dose’ to people around the nuclear sites. It considers the effects of all sources, that is the discharges of gaseous and liquid wastes and direct radiation from sources on the site premises (Camplin and others 2005). The stages of the assessment are described below.

  1. Using the consumption and occupancy data from habits surveys.

  2. Use the ‘cut-off’ method to group individuals whose consumption or occupancy is within a factor of 3 of the observed maximum, for example, identify all high-rate crustacean consumers.

  3. Habits profiles for the group determined by averaging the habits rates of all individuals in the group, take the average of all the habits data for crustacean consumers.

  4. Repeat steps 2 and 3 for all pathways identified in habits survey (for example, occupancy for direct radiation, milk consumption).

  5. Doses to each profiled group calculated (using concentrations of radionuclides in food and environmental dose rates). The group with the highest dose near each site becomes the representative person.

The second type of assessment is focused on specific sources and their associated pathways (see Section 1.2 and Appendix 2 in this report for additional information). It serves as a check on the robustness of the ‘total dose’ assessment and is also compatible with the approach used prior to the introduction of ‘total dose’ in 2004.

‘Total dose’ assessments include direct radiation. The estimates of direct radiation dose are provided by The Office for Nuclear Regulation (ONR) based on information supplied by industry (Coleby 2025). Both types of assessment provide information on 2 other main pathways:

  • ingestion of foodstuffs
  • external exposure from contaminated materials in the aquatic environment

Collective doses are beyond the scope of this report. They are derived using modelling techniques. The European Commission has published an assessment of individual and collective doses from reported discharges from nuclear power stations and reprocessing sites for gaseous and liquid waste disposals from 2004 to 2008 (Jones and others 2013).

Monitoring data is also used to assess doses from other pathways (Allott 2009) :

  • drinking water
  • inadvertent ingestion of water and sediments
  • inhalation of re-suspended soil and sediment

In addition, models are used to supplement the monitoring data in 4 situations:

  • atmospheric dispersion models are used for non-food pathways where monitoring is not an effective method of establishing concentrations or dose rates in the environment
  • food chain models provide additional data to fill gaps and to adjust for high limits of detection
  • modelling of exposures of sewage workers is undertaken for discharges from the Atomic Weapons Establishment (AWE) Aldermaston and the Grove Centre, Amersham

Full details of the models used are given in Appendix 3.

For pathways involving intakes of radionuclides, the data required for assessment are:

  • concentrations in foodstuffs, drinking water sources, sediments or air
  • the amounts eaten, drunk or inhaled
  • the dose coefficients that relate an intake or activity to a dose

For external radiation pathways, the data required are:

  • the dose rate from the source, for example a beach or fisher’s nets
  • the time spent near the source

In both cases, the assessment estimates exposures from these pathways for people who are likely to be most exposed.

2.8. Concentrations of radionuclides in foodstuffs, drinking water sources, sediments and air

In nearly all cases, the concentrations of radionuclides are determined by monitoring and are given in the main text of this report. The concentrations chosen for the assessment are intended to be representative of the intakes of the most exposed consumers in the population. All of the positively determined concentrations tabulated are included irrespective of the origin of the radionuclide. In some cases, this means that the calculated exposures could include contributions due to disposals from other sites as well as from fallout from nuclear weapon testing and activity deposited following a nuclear reactor accident (such as at Chernobyl in 1986). Where possible, corrections for ‘background’ concentrations of naturally occurring radionuclides are made in the calculations of dose (see Section 2.12).

For aquatic foodstuffs, drinking water sources, sediments and air, the assessment is based on the mean concentration near the site in question. For milk, the mean concentration at a nearby farm with the highest individual result is used in the dose assessment. This procedure accounts for the possibility that any farm close to a site can act as the sole source of supply of milk to high-rate consumers.

For other foodstuffs, the maximum activity concentrations are selected for the assessment. This allows for the possibility of storage of food harvested at a particular time when the peak quantities in a year may have been present in the environment.

The tables of activity concentrations include ‘less than’ values as well as positive determinations. This is particularly evident for gamma-ray spectrometry of terrestrial foodstuffs. Where a result is presented as a ‘less than’‘ value, the dose assessment methodology treats it as if it were a positive determination in the following scenarios:

  1. When that radionuclide is specified in the relevant permit or authorisation (gaseous or liquid).

  2. When that radionuclide was determined using radiochemical methods.

  3. When a positive result is reported for that radionuclide in another sample from the same sector of the environment at the site (aquatic or terrestrial).

Although this approach may produce an overestimation of dose, particularly at sites where activity concentrations are low, it ensures that estimated exposures are unlikely to be understated.

2.9. Consumption, drinking and inhalation rates

2.9.1. Source specific assessments

In the assessment of the effects of disposals of liquid effluents, the amounts of fish and shellfish consumed are determined by site-specific dietary habits surveys. Data are collected primarily by direct interviews with potential high-rate consumers who are often found in fishing communities. Children are rarely found to eat large quantities of seafood, and their resulting doses are invariably less than those of adults. The calculations presented in this report are therefore representative of adult seafood consumers or their unborn children if the prenatal children age group is more restrictive.

In assessments of terrestrial foodstuffs, the amounts of food consumed are derived from national surveys of diet and are defined for 3 age groups: adults, children (10-year-old) and infants (1-year-old) (based on Byrom and others 1995). Adult consumption rates are used in the assessment of doses to prenatal children. For each food type, consumption rates at the 97.5th percentile of consumers have been taken to represent the people consuming a particular foodstuff at a high rate (the consumption rate of the ‘representative person’).

Drinking and inhalation rates are general values for the population, adjusted according to the times spent in the locations being studied.

The consumption, drinking and inhalation rates are given in Appendix 4. Estimates of dose are based on the most up to date information available at the time of writing the report. Where appropriate, the data from site-specific surveys are averaged over a period of 5 years following the recommendation of the report of the consultative exercise on dose assessments (CEDA) (Food Standards Agency 2001).

The assessment of terrestrial foodstuffs is based on 2 assumptions:

  • that the foodstuffs eaten by the most exposed individuals are those that are sampled for the purposes of monitoring, see references (Swift 2002a; Centre for Environment Fisheries and Aquaculture Science no date) for previous investigations into key marine environmental indicators and uncommon seafoods, respectively
  • that the consumption of such foodstuffs is sustained wholly by local sources

The 2 food groups resulting in the highest dose are taken to be consumed at high consumption rates, while the remainder are consumed at mean rates. The choice of 2 food groups at the higher consumption rates is based on statistical analysis of national diet surveys. This shows that only a very small percentage of the population were critical rate consumers in more than 2 food groups (Ministry of Agriculture Fisheries and Food 1996). Locally grown cereals are not considered in the assessment of exposures as it is considered highly unlikely that a significant proportion of cereals will be made into locally consumed (as opposed to nationally consumed) foodstuffs, notably bread.

2.9.2. ‘Total dose’ assessments

The ‘total dose’ assessments are based on consumption and occupancy data collected from site specific surveys which are targeted at those most likely to be exposed around the site. The habits profiles that give rise to the highest doses in the assessment of RIFE data are given in files that accompany this report and are available from the main RIFE page. Care should be taken in using these data in other circumstances because the profile leading to the highest doses may change if the measured or forecast concentrations and dose rates change.

2.10. Dose coefficients

Dose calculations for intakes of radionuclides by ingestion and inhalation are based on the compendium of dose coefficients taken from ICRP Publication 119 (International Commission on Radiological Protection 2012) and from ICRP 88 (International Commission on Radiological Protection 2001) and National Radiological Protection Board (NRPB) (Oatway, Simmonds & Harrison 2008). In mid-2024, ICRP launched the consultation on the publication of revised dose coefficients to members of the public (part 2).

These coefficients (often referred to as ‘dose per unit intake’) relate the committed dose received to the amount of radioactivity ingested or inhaled. The dose coefficients used in this report are provided in Appendix 5 for ease of reference. Dose coefficients are available for multiple age groups.

The dose assessments include the use of appropriate gut uptake factors (proportion of radioactivity being absorbed from the digestive tract). Where there is a choice of gut uptake factors for a radionuclide, we have generally chosen the one that gives the highest predicted exposure. Where results for total tritium are available, we have assumed that the tritium content is wholly in an organic form. However, we have also considered specific research work of relevance to the foods considered in this report. This affects the assessments for tritium, polonium, plutonium, and americium radionuclides as discussed in Appendix 5.

2.11. External exposure

In the assessment of external exposure, there are 2 factors to consider:

  • the dose rate from the source
  • the time spent near the source

In the case of external exposure to penetrating gamma radiation, uniform whole-body exposure has been assumed. The radiation as measured is in terms of the primary quantity known as ‘air kerma rate’, a measure of the energy released when the radiation passes through air. This has been converted into exposure using the factor 1 milligray = 0.85mSv (International Commission on Radiological Protection 2010). This factor applies to a rotational geometry with photon energies ranging from 50keV to 2MeV. This is appropriate for the instrument used whose sensitivity is much reduced below 50keV, and to the geometry of deposits of artificial radionuclides. Applying an isotropic geometry gives a value of 0.70Sv Gy-1, which would be more appropriate for natural background radiation. The choice of 0.85 will therefore tend to overestimate dose rates for the situations considered in this report which include both artificial and natural radiation.

For external exposure of skin, the measured quantity is radiological contamination in Bq cm-2. In this case, dose rate factors in Sv y-1 per Bq cm-2 are used, which are calculated for a depth in tissue of 7mg cm-2 (Kocher & Eckerman 1987). The time spent near sources of external exposure are determined by site-specific habits surveys in a similar manner to consumption rates of seafood. The occupancy and time spent handling fishing gear are given in Appendix 4.

2.12. Subtraction of ‘background’ activity concentrations

For assessing internal exposures in seafood due to the ingestion of carbon-14 and radionuclides in the uranium and thorium decay series, ‘background’ activity concentrations are subtracted. Background carbon-14 concentrations in terrestrial foods are also subtracted. The estimates of background activity concentrations are given in Appendix 6. For assessing the artificial effect on external exposures to gamma radiation, dose rates due to background are subtracted. Since measurements were made previously as part of the monitoring programmes reported here, the gamma dose rate backgrounds in the aquatic environment are taken to be 0.05µGy h-1 for sandy substrates, 0.07µGy h-1 for mud and salt marsh and 0.06µGy h-1 for other substrates. These data are compatible with those presented in (McKay and others 1995). Where it is difficult to distinguish the result of a dose rate measurement from natural background, the method of calculating exposures based on the concentrations of artificial radionuclides in sediments is used (Hunt 1984). Estimates of external exposures to beta radiation include a component due to naturally occurring (and un-enhanced) sources because of the difficulty in distinguishing between naturally occurring and artificial contributions. Such estimates are therefore conservative, compared with the relevant dose limit that excludes natural sources of radiation.

2.13. Uncertainties in dose assessment

Various methods are used to reduce the uncertainties in the process of the dose estimation of the representative person. These address the following main areas of concern:

  • programme design
  • sampling and in situ measurement
  • laboratory analysis
  • description of pathways to humans
  • radiation dosimetry
  • calculational and presentational error

Quantitative estimation of uncertainties in doses is beyond the scope of this report.

3. Nuclear fuel production and reprocessing

Highlights

  • ‘total dose’ for the representative person were 22% (or less) of the annual dose limit for all assessed sites and locations.

Capenhurst, Cheshire

  • ‘total dose’ for the representative person was 0.22mSv and increased in 2024 compared to 2023

Springfields, Lancashire

  • ‘total dose’ for the representative person was 0.017mSv and decreased in 2024 compared to 2023

Cumbrian coastal area, including Sellafield, Cumbria

  • ‘total dose’ for the Cumbrian coastal community were 0.20mSv (or less) and decreased in 2024 compared to 2023
  • the highest ‘total dose’ was from seafood, dominated by the effects of historical discharges of naturally occurring radionuclides from the former phosphate processing plant near Whitehaven. Historical discharges from the Sellafield site made a lesser contribution
  • radiation dose from historical discharges of naturally occurring radionuclides was lower in 2024 compared to 2023, but still dominant. The contribution to ‘total dose’ from Sellafield discharges (both historical and current) and sources of direct radiation from the LLWR decreased in 2024 compared to 2023
  • gaseous discharges from Sellafield of plutonium-alpha, and americium-241 and curium-242 were slightly higher, in 2024 compared to 2023
  • liquid discharges from Sellafield were generally lower, in 2024 compared to 2023

This section considers the results of monitoring, by the Environment Agency, FSA, NIEA and SEPA, of 3 sites in the UK associated with civil nuclear fuel production and reprocessing. Data tables and the detailed results of the dose assessments, in Open Document Spreadsheet (ODS) format, are downloadable from the main RIFE page.

3.1. Capenhurst, Cheshire

The Capenhurst site is located near Ellesmere Port and is home to uranium enrichment plants and associated facilities. The major operators at the site are Urenco UK Limited (UUK), Urenco Nuclear Stewardship Limited (UNS) and Urenco Chemplants Limited (UCP); they each have their own permits. UUK operates 3 plants producing enriched uranium for nuclear power stations. UNS manages assets owned by the NDA, comprising uranic material storage facilities and activities associated with decommissioning, UNS also manage radioactive wastes on behalf of all 3 operators. UCP are currently commissioning a new facility on a separate part of the site, to allow safer long-term storage of depleted uranium. This facility, the Tails Management Facility, de-converts uranium hexafluoride (UF6 or “Hex”) to uranium oxide (U3O8). This allows the uranium to be stored in a more chemically stable oxide form for potential future reuse in the nuclear fuel cycle. This process recovers hydrofluoric acid for reuse in the chemical industry. The plant is permitted to discharge gaseous waste to the environment, aqueous waste to UUK’s effluent disposal system and will dispose of solid waste by off-site transfer.

The most recent habits survey to determine the consumption and occupancy rates by members of the public was undertaken in 2021 (Moore, Clyne & Greenhill 2022).

3.1.1. Doses to the public

The ‘total dose’ from all pathways and sources of radiation was 0.22mSv in 2024 (Table 3.1), or 22% of the dose limit to members of the public. This is an increase from 0.15mSv in 2023 due to a higher estimate of direct radiation, which is the dominant contribution to dose, from the site. The representative person was a child living close to the site, a change from 2023 (an adult exposed to direct radiation close to the site). The trend in annual ‘total dose’ over the period 2013 to 2024 is given in Figure 3.1. The ‘total dose’ at Capenhurst ranged from 0.080mSv in 2013 to 0.22mSv in 2024 and all were below the dose limit to members of the public. Any changes in annual ‘total dose’ over time were due to changes in the estimates of direct radiation from the site.

Figure 3.1. ‘Total dose’, in mSv y-1, at Capenhurst, 2013 to 2024.
Year Dose
Dose limit 1.0
2013 0.080
2014 0.17
2015 0.13
2016 0.17
2017 0.17
2018 0.16
2019 0.17
2020 0.17
2021 0.17
2022 0.14
2023 0.15
2024 0.22

Source specific assessments for high-rate consumers of locally grown foods, and for children playing in and around Rivacre Brook, give exposures that were less than the ‘total dose’ in 2024 (Table 3.1). The dose for children (10-year-old), who play in and around the brook and may inadvertently ingest water and sediment, was 0.007mSv in 2024 (up from 0.006mSv in 2023). The increase in dose was due to higher gamma dose rates measured over the riverbank at Rivacre Brook in 2024. The dose is estimated using cautious assumptions for occupancy of the bank of the brook, inadvertent ingestion rates of water and sediment, and gamma dose rates.

3.1.2. Gaseous discharges and terrestrial monitoring

Uranium is the main radioactive constituent of gaseous discharges from Capenhurst (Table A1.1), with small amounts of other radionuclides present in discharges by UNS. The focus for terrestrial sampling was the analyses of technetium-99 and uranium in food (including milk), grass and soil. Results for 2024 are given in Table 3.2(a). Concentrations of radionuclides in milk and food samples around the site were very low and generally similar to those in previous years. As in 2023, isotopes of uranium in silage were enhanced by small amounts (most likely due to natural variation) in 2024. Figure 3.2(a) shows the trends over time (2013 to 2024) of low technetium-99 discharges and corresponding technetium-99 concentrations in grass. The overall trend reflects the reductions in discharges of technetium-99 from the enrichment of reprocessed uranium in the past. The most recently observed variability (from year to year) in the technetium-99 concentrations is based on data reported as less than values. Discharges of uranium are also given in Figure 3.2(b) and are low over the period 2013 to 2024.

Figure 3.2(a). Technetium-99 concentrations in grass, in Bq kg-1 (fresh), and annual discharges, in MBq y-1 at Capenhurst, 2013 to 2024.
Figure 3.2(b). Gaseous uranium annual discharges, in MBq y-1, 2013 to 2024.

3.1.3. Liquid waste discharges and aquatic monitoring

The permit for the UUK Capenhurst site allows liquid waste discharges to the Rivacre Brook for uranium and uranium daughters, technetium-99 and non-uranium alpha (mainly neptunium-237) as shown in Table A1.2. Monitoring included the collection of samples of fish and shellfish from the local aquatic and downstream marine environment (for analysis of a range of radionuclides) and of freshwater and sediments for the analysis of tritium, technetium-99, gamma-emitting radionuclides, uranium, neptunium-237, and gross alpha and beta. Dose rate measurements were taken on the banks of the Rivacre Brook and surrounding area. Results for 2024 are given in Table 3.2(a) and Table 3.2(b). Concentrations of radionuclides in foods from the marine environment were very low and generally similar to those in previous years. The concentrations in fish and shellfish reflect the distant effects of discharges from Sellafield as observed in previous monitoring reports, such as the Fisheries Radiobiological Laboratory report series, Aquatic Environment Monitoring Report series and earlier RIFE reports.

As in previous years, sediment samples collected downstream from the Rivacre Brook contained very low but measurable concentrations of uranium (enhanced above natural concentrations) and technetium-99. As expected, enhanced concentrations of these radionuclides (and others) were measured close to the discharge point (Rivacre Brook). Technetium-99 and uranium radionuclide concentrations from this location were lower in 2024, compared to 2023, but similar to those in other recent years. Variations in concentrations in sediment from the brook are also to be expected due to differences in the size distribution of sedimentary particles. Concentrations of radionuclides in freshwaters at the discharge point (and at other freshwater locations) were very low in 2024. Measured gamma dose rates near to the discharge point were higher in 2024, compared to 2023 (where comparisons can be made for similar ground types and locations). Downstream of the Rivacre Brook, at the location where children play, dose rates over grass were also higher in 2024.

Figure 3.2(c-g) shows the trends over time in discharges and activity concentrations in environmental samples. These include uranium, ‘uranium daughters’ and ‘non-uranic alpha’ discharges and during the period 2013 to 2024. The overall trend was a reduction of liquid discharges over time, mostly attributed to progress in decommissioning of older plant and equipment.

Figure 3.2(c). Liquid uranium annual discharges, in MBq y-1, 2013 to 2024.
Figure 3.2(d). Liquid uranium daughters annual discharges, in MBq y-1, 2013 to 2024.
Figure 3.2(e). Liquid non-uranic annual discharges, in MBq y-1,2013 to 2024.
Figure 3.2(f). Caesium-137 and americium-241 concentrations in sediment, in Bq kg-1 (dry), at Rock Ferry, 2013 to 2024.
Figure 3.2(g). Technetium-99 concentrations in sediment, in Bq kg-1 (dry), at Rivacre Brook, 2013 to 2024.

Concentrations of technetium-99 in sediment (Rivacre Brook) from liquid discharges were detectable close to the discharge point in 2024. The trend of technetium-99 in sediment is given in Figure 3.2(g) concentrations in 2017 were higher than adjoining years as discussed in RIFE 23 (Environment Agency, Food Standards Agency, Food Standards Scotland, Natural Resources Wales and others 2018).

Concentrations of caesium-137 and americium-241 in sediments at Rock Ferry on the Irish Sea coast were from past discharges from Sellafield carried into the area by tides and currents (Figure 3.2(f)). The concentrations were generally similar over most of the time period and any fluctuations were most likely due to the effects of normal dispersion in the environment. The lowest activity concentrations at Rock Ferry were reported in 2016.

3.2. Springfields, Lancashire

The Springfields site near Preston, is operated by Springfields Fuels Limited (SFL). The site is owned by the NDA and leased to Westinghouse Electric Company UK Limited, the parent company of Springfields Fuels Limited (SFL). The main commercial activity is the manufacture of fuel elements for nuclear reactors and the deconversion of uranium hexafluoride to produce powders and pellets for other fuel manufacturers. Other important activities include recovery of uranium from residues and decommissioning redundant plants and buildings, under contract to the NDA, who retain responsibility for the historical nuclear liabilities on the site.

Research and development, carried out by the UK National Nuclear Laboratory (UKNNL), produces small amounts of other gaseous radionuclides that are also discharged under the permit (see Appendix 1, Table A1.1).

Monitoring around the site is carried out to check not only for uranium concentrations, but also for other radionuclides discharged in the past (such as actinide decay products from past discharges when uranium ore concentrate (UOC) was the main feed material) and for radionuclides discharged from Sellafield. The monitoring locations (excluding farms) are shown in Figure 3.3. The corresponding sample types and locations are listed in the corresponding site tables.

Figure 3.3. Monitoring locations at Springfields, 2024 (not including farms).

The most recent habits survey was undertaken in 2022 (Clyne and others 2023). In the 2022 survey, no houseboat dwellers were recorded, therefore this assessment was discontinued. Figures for consumption rates, together with occupancy and handling rates, are provided in Appendix 4 (Table A4.2).

3.2.1. Doses to the public

The ‘total dose’ from all pathways and sources of radiation was 0.017mSv in 2024 (Table 3.1), or less than 2% of the dose limit to members of the public. This is a decrease from 0.040mSv in 2023 and mainly attributed to a lower estimate of direct radiation from the site, in comparison to that in 2023. In 2024, the representative person was an infant living near to the site and unchanged from 2023. Most of the dose to the representative person was from direct radiation. The trends of ‘total dose’ over the period 2013 to 2024 are given in Figure 3.4 and are generally low over this period, the increase observed in 2019 was due to a higher estimate of direct radiation caused by increased occupancy of some workers undertaking a specific responsibility (associated with the rail line) close to the site.

Source specific assessments give exposures that were all less than the ‘total dose’ in 2024 (Table 3.1) for:

  • consumers of locally grown food and of seafood (including wildfowl)
  • farmers spending time on the banks of the estuary
  • children playing on the banks of the estuary

Trends in source-specific doses for a high-rate houseboat dweller are presented in earlier RIFE reports.

Figure 3.4. ‘Total dose’, in mSv y-1, at Springfields (2013 to 2024).
Year Dose
Dose limit 1.0
2013 0.060
2014 0.050
2015 0.050
2016 0.038
2017 0.028
2018 0.075
2019 0.14
2020 0.047
2021 0.031
2022 0.032
2023 0.040
2024 0.017

The dose for high-rate consumers of seafood and wildfowl was 0.009mSv in 2024, with approximately 0.006mSv from external exposure (the remainder being from consumption of fish, crustaceans and wildfowl) and slightly higher than that in 2023 (0.007mSv). The most important radionuclides were caesium-137 and americium-241 from historical discharges from Sellafield.

A source specific assessment for external exposure to farmers was less than 0.005mSv in 2023 (Table 3.1) and unchanged from 2023. The estimated doses to high-rate consumers of locally grown food, and to children playing on the banks of the estuary were all less than 0.005mSv in 2024.

It has been previously shown that assessed annual doses to the public from inhaling sediment from the Ribble Estuary, re-suspended into the air, were much less than 0.001mSv, and negligible in comparison with other exposure routes (Rollo and others 1994).

3.2.2. Gaseous discharges and terrestrial monitoring

Uranium is the main radioactive constituent of gaseous discharges, with small amounts of other radionuclides present in discharges from UKNNL research and development facilities (Table A1.1).

The focus of the terrestrial sampling was for the analyses of tritium, carbon-14, strontium-90, iodine-129, and isotopes of uranium, thorium, plutonium and americium in milk and vegetables. Grass, soil and freshwater samples were collected and analysed for isotopes of uranium. Data for 2024 are given in Table 3.3(a). Uranium isotope concentrations in pumpkin were similar to those in beetroot in 2023. Concentrations of thorium were also low in vegetable and grass samples. As in previous years, elevated concentrations of uranium isotopes were measured in soils around the site, but the isotopic ratio showed that they were most likely to be naturally occurring. Overall, results were broadly similar to those of previous years.

Figures 3.5(a) and 3.5(b) shows the trends over time (2013 to 2024) of gaseous uranium discharges and total uranium radionuclide concentrations in food (cabbage; 2013: beetroot; 2014 to 2023; pumpkin; 2024). Over the period, uranium discharges have declined, with the lowest value reported from this site in 2022. Total uranium was detected in cabbage, beetroot and pumpkin samples during the period, as given in Figure 3.5(g), but the concentrations were very low. The apparent peak of uranium in beetroot in 2017 was also low and significantly less than that found in soil samples.

Figure 3.5(a). Discharges of gaseous uranium, in TBq y-1, Springfields 2013 to 2024.
Figure 3.5(b). Concentrations of total uranium in terrestrial food, in Bq kg-1 (fresh), Springfields 2013 to 2024.

3.2.3. Liquid waste discharges and aquatic monitoring

Permitted discharges of liquid waste (including gross alpha and beta (Figure 3.5(c)), technetium-99 (Figure 3.5(d)), thorium-230, thorium-232, neptunium-237 (Figure 3.5(e)), uranium (Figure 3.5(f)) and ‘other transuranic radionuclides’ (Figure 3.5(g)) are made from the Springfields site to the Ribble Estuary via 2 pipelines (Table A1.2). All discharges were generally similar in 2024, compared to 2023. Compared to previous years, discharges are now generally lower for beta-emitting radionuclides. This includes the short half-life beta-emitting radionuclides (mostly thorium-234) that have decreased following the end of the UOC purification process in 2006. Production of uranium hexafluoride ceased in 2014, and the associated plants mothballed. This has led to a corresponding reduction in discharges of uranium in recent years. Discharges of technetium-99 depend almost entirely on which legacy uranic residues are being processed. Since completion of one particular residue processing campaign (in 2012), technetium-99 discharges have generally declined, with the lowest value (reported as <1% of the annual limit) from this site in 2021. The Ribble Estuary monitoring programme consisted of ‘in situ’ dose rate measurements, the collection and analysis of sediments for uranium and thorium isotopes and gamma-emitting radionuclides.

Figure 3.5(c). Discharges of liquid beta, in TBq -1, Springfields 2013 to 2024.
Figure 3.5(d). Discharges of liquid technetium-99, in TBq -1, Springfields 2013 to 2024.
Figure 3.5(e).Discharges of liquid neptunium-237, in TBq -1,Springfields 2013 to 2024.
Figure 3.5(f). Discharges of liquid uranium, in TBq -1,Springfields 2013 to 2024.
Figure 3.5(g). Discharges of liquid other transuranic nuclides, in TBq -1, Springfields 2013 to 2024.<

Results for 2024 are shown in Table 3.3(a). As in previous years, radionuclides due to discharges from both Springfields and Sellafield were detected in sediment and biota in the Ribble Estuary. Radionuclides found in the Ribble Estuary originating from Sellafield were technetium-99, caesium-137 and americium-241. Isotopes of uranium and the short half-life radionuclide thorium-234 were also found from Springfields. Concentrations of the latter were closely linked to recent discharges from the Springfields site. In 2023, thorium-234 concentrations in sediments (over the range of sampling sites) were generally similar compared to those in 2023. Over a much longer timescale these concentrations have declined due to reductions in discharges as shown by the trend of sediment concentrations at the outfall (Figure 3.5(h)), Lower Penwortham and Becconsall (Environment Agency, Food Standards Agency, Food Standards Scotland, Natural Resources Wales and others 2018). The most significant change in the discharge trends was the step reduction of short half-life beta-emitting radionuclides in liquid discharges, mostly thorium-234. The reduction was because the UOC purification process ended in 2006. In more recent years, thorium-234 concentrations have generally declined by small amounts in sediments at Lower Penwortham and Becconsall (Figures 3.5(i and j)), with the lowest values reported at Lower Penwortham and the outfall in 2023.

Figure 3.5(h). Concentrations of caesium-137 (multiplied by 100), thorium-234 and americium-241 (multiplied by 100) in sediment, in Bq kg-1, at the outfall, 2013 to 2024.
Figure 3.5(i). Concentrations of caesium-137 (multiplied by 10), thorium-234 and americium-241 (multiplied by 10) in sediment, in Bq kg-1, at Lower Penwortham Park, 2013 to 2024.
Figure 3.5(j).Concentrations of caesium-137 (multiplied by 10), thorium-234 and americium-241 (multiplied by 10) in sediment, in Bq kg-1, at Becconsall, 2013 to 2024.

Caesium-137 and americium-241 radionuclides were detected in biota and sediments from the Ribble Estuary in 2024, due to historical liquid discharges from Sellafield, carried from west Cumbria into the Ribble Estuary by sea currents and adsorbed on fine-grained muds. The concentrations observed were generally similar to those in recent years.

Figures 3.5 (k and l) also provides trend information over time (2013 to 2024) for several other permitted radionuclides and activity concentrations in flounder and shrimp. Liquid discharges of uranium radionuclides steadily decreased (and other discharges to a lesser extent) over the whole period, whilst technetium-99 discharges generally decreased overall (but peaked in 2012 and 2017). Caesium-137 concentrations in flounder showed variations between years and this was most likely due to natural changes in the environment, although there is evidence of decreasing concentrations overall. Technetium-99 concentrations in shrimp showed variations between years and this was most likely due to natural changes in the environment, with lower concentrations observed as discharges have decreased in recent years.

Figure 3.5(k). Concentrations of technetium-99 in shrimps, in Bq kg-1 (fresh), Springfields 2013 to 2024.
Figure 3.5(l). Concentrations of caesium-137 in flounder, in Bq kg-1 (fresh), Springfields 2013 to 2024.

Gamma dose rates (Table 3.3(b)) in the estuary were generally higher than expected natural background rates (see Section 2.12), due to discharges of gamma-emitting radionuclides (caesium-137 and americium-241) from Sellafield. In 2024, gamma dose rates in the estuary, were generally higher (by small amounts) to those in 2023, but with some small variations at some sites. Beta dose rates over salt marsh (where comparisons can be made) were similar to those in recent years.

3.3. Cumbrian coastal area including Sellafield, Cumbria

This section considers both historic and present activities in the Cumbrian coastal area that have led to discharges of radioactive waste, including Sellafield where a range of decommissioning and waste management activities are carried out.

The area is impacted by several sources of radioactivity, these are:

  • naturally occurring radionuclides from historical discharges from the former phosphate processing plant near Whitehaven
  • artificial radionuclides from both historical and current discharges from Sellafield to both the marine and terrestrial environments
  • liquid discharges from LLWR
  • direct radiation from Sellafield
  • direct radiation from the LLWR

The discharges impact upon the same area, therefore this section presents a dose to the Cumbrian Coastal Community from all sources. A separate assessment of doses from Sellafield only is also presented. Separate assessments for the LLWR and the former phosphate processing plant are given in Sections 7.1 and 7.5 respectively.

The former phosphate processing plant which closed in 2004 was near Whitehaven in Cumbria. Although phosphoric acid production at the plant ceased in 1992, with a corresponding reduction in discharges to the Irish Sea (Rollo and others 1992), the effects of these past operations continue due to the ingrowth of decay products from the long-lived parent radionuclides discharges by the plant to the Irish Sea. Naturally occurring radionuclides from this historic industrial activity are monitored and assessed (see Section 7.5).

Sellafield Limited is responsible for the operation of the Sellafield site and is a wholly owned subsidiary of the NDA. In 2024, the main operations at Sellafield were:

  • post-operational clean out at the Magnox reprocessing facility
  • the decommissioning and clean-up of redundant nuclear facilities including Calder Hall nuclear power station, Windscale reactors and the Thermal Oxide Reprocessing Plant (THORP)
  • waste treatment and storage of radioactive materials

Nuclear fuel reprocessing at THORP ceased in 2018, resulting in reduced gaseous and liquid discharges in the intervening period. THORP will continue to serve the UK until the 2070s as a storage facility for spent AGR fuel. In July 2022, the Magnox reprocessing facility took its final feed of spent nuclear fuel marking the end of 58 years of Magnox fuel reprocessing. The facility will now enter the post-operational clean-out phase.

Monitoring of the environment and food in the Cumbrian Coastal area including around Sellafield reflects the historical and current activities the components of the programme are considered here in depth. The discussion is provided in 4 sub-sections, relating to the assessment of dose, the effects of gaseous discharges, the effects of liquid discharges and unusual pathways of exposure identified around the site.

A full habits survey is conducted every 5 years around the Cumbrian coastal area in the vicinity of the Sellafield site, which investigates the exposure pathways relating to current and historical liquid and gaseous discharges, and to direct radiation. Annual review surveys are also undertaken between the full habits surveys that investigate the pathways relating to liquid discharges, review high-rate fish and shellfish consumption by local people and review their intertidal occupancy rates. The most recent full Sellafield habits survey was conducted in 2023 (Moore and others 2024a). A full survey around the LLWR was also performed in 2023 (Moore and others 2024b). In 2024, some changes were found in the amounts (and mixes) of seafood species consumed and intertidal occupancy rates (Moore, Clyne & Greenhill 2025). Revised figures for consumption rates, together with occupancy rates, are provided in Appendix 4 (Table A4.2). Further afield, the most recent habits surveys were conducted to determine the consumption and occupancy rates by members of the public on the Dumfries and Galloway coast in 2024 (available upon request from SEPA by emailing RSEnquiries@sepa.org.uk) and around Barrow and the south-west Cumbrian coast in 2012 (Garrod CJ and others 2013a). The results of these surveys are used to determine the potential exposure pathways, related to liquid discharges from Sellafield.

Habits surveys to obtain data on activities undertaken on beaches relating to potential public exposure to radioactive particles in the vicinity of the Sellafield nuclear site were undertaken in 2007 and 2009 (Clyne and others 2008; Clyne and others 2010).

3.3.1. Doses to the Cumbrian coastal community

The doses calculated in this section cover a wide area and consider the inputs from several sources:

  • naturally occurring radionuclides from the non-nuclear activity from the former phosphate processing plant in Whitehaven
  • artificial radioactivity from both historical and current discharges from Sellafield to both the marine and terrestrial environments
  • sources of direct radiation from Sellafield
  • liquid discharges from the LLWR
  • sources of direct radiation from the LLWR

Liquid discharges from Wylfa, Chapelcross, Barrow and Heysham also have a very small impact on doses but are not considered in this report.

3.3.1.1. ‘Total dose’ from all pathways and sources to the Cumbrian coastal community

In 2024, the highest ‘total dose’ to the Cumbrian coastal community, near Sellafield, was assessed to have been 0.20mSv[footnote 6] (Table 3.16), or 20% of the dose limit to members of the public. The dose is broken down as follows:

  • 0.18mSv from historical discharges of naturally occurring radionuclides from the former phosphate processing plant at Whitehaven, a decrease from 0.21mSv in 2023
  • 0.018mSv from discharges of artificial radionuclides (including external radiation) from Sellafield, a decrease from 0.019mSv in 2023. 0.007mSv of this was from sources of direct radiation from the LLWR

This is a decrease from 0.23mSv in 2023, which was mostly attributed to lower polonium-210 concentrations in crabs and lobsters. Polonium-210 (and lead-210) are important radionuclides as small changes in concentrations above the natural background of these radionuclides, significantly influence the dose contribution from these radionuclides (due to a relatively high dose coefficient used to convert an intake of radioactivity into a radiation dose) and therefore the value of the estimated dose. The assessment is cautious as the liquid discharges from all sites go into the same area.

The representative person was an adult consuming crustacean shellfish at high rates who also consumed significant quantities of other seafood (fish) and was unchanged from 2023. The annual ‘total dose’ from all pathways and sources of radiation is assessed using consumption and occupancy data from the full habits survey of 2023 (Moore and others 2024b) and the yearly review of shellfish and fish consumption, and intertidal occupancy in 2024 (Moore, Clyne & Greenhill 2025). Calculations are performed for 4 age groups (adults, 10-year-old children, 1-year-old infants and prenatal children).

The most significant pathway contributions[footnote 7] to the ‘total dose’ in 2024 were from crustacean consumption (94%), direct radiation (from the LLWR) (3%), fish consumption (1%), external exposure over intertidal substrates (1%) and other pathways (1%). The listed food groups are consumption pathways, the other pathways include external exposure over sediment and salt marsh. The most important radionuclide was polonium-210 (90%) with transuranic radionuclides (including plutonium-239+240 and americium-241) contributing less than 3% of the dose.

The contributions from artificial radionuclides from Sellafield (0.018msv in 2024) to the ‘total dose’ were mostly iodine-129 (15%, based on concentrations reported at the limit of detection), americium-241 (18%) and plutonium radionuclides (4%). External exposure contributed 48% of the ‘total dose’ from artificial radionuclides (61% in 2023).

Contributions to the highest annual ‘total dose’ each year (2013 to 2024), from all pathways and sources by industry, are given in Figure 3.6. Inter-annual variations were more complex and governed by both natural variability in seafood concentrations and real changes in the consumption and occupancy characteristics of the local population. Over a longer period, the trend is of generally declining dose (Environment Agency, Food Standards Agency, Food Standards Scotland, Natural Resources Wales and others 2018). In 2013, the highest dose was to people living on houseboats near Barrow (external exposure only), the reasons for dose in 2013 and the changes in dose between 2013 and 2014 are described in the relevant RIFE reports (Environment Agency, Food Standards Agency, Natural Resources Wales and others 2014; Environment Agency, Food Standards Agency, Food Standards Scotland and others 2016). From 2014, the relative changes in dose were largely due to variations in polonium-210 concentrations in locally caught lobsters and crabs.

Figure 3.6. Contributions from the nuclear industry (Sellafield and the LLWR) and the former phosphate processing plant to ‘total dose’, in mSv y-1, from all sources along the Cumbrian Coast, 2013 to 2024. (The highest ‘total dose’ in 2013 due to Sellafield discharges was to people living on houseboats (external exposure only) near Barrow in Cumbria).
Year Dose from the Nuclear Industry (Sellafield and the LLWR), mSv y-1 Dose from the Former phosphate processing plant at Whitehaven, mSv y-1 Total, mSv y-1
2013 0.076 0 0.076
2014 0.068 0.15 0.22
2015 0.078 0.35 0.42
2016 0.074 0.34 0.42
2017 0.077 0.18 0.25
2018 0.034 0.33 0.37
2019 0.055 0.20 0.25
2020 0.058 0.25 0.31
2021 0.019 0.19 0.21
2022 0.014 0.22 0.24
2023 0.019 0.21 0.23
2024 0.018 0.18 0.20

The contributions, from all pathways and sources, to the highest annual ‘total dose’ from the nuclear industry (primarily Sellafield), from external exposure and ingestion or inhalation of radionuclides, and by radionuclide, are also given in Figure 3.7 (2013 to 2024) and Figure 3.8 (2013 to 2024), respectively. The overall trend from the nuclear industry is a generally declining dose (Figure 3.7), broadly reflecting a general reduction of concentrations in seafood of artificial radionuclides from the nuclear industry and changes in habits information, over this period. The pathways of exposure contributing the highest dose were consumption of mollusc, crustacean and sea fish.

Figure 3.7. Contributions from nuclear industry (external exposure, and ingestion and inhalation doses), primarily from Sellafield, (external exposure, and ingestion and inhalation doses) to ‘total dose’, in mSv y-1, from all sources along the Cumbrian Coast, 2013 to 2024. (The highest ‘total dose’ in 2013 due to Sellafield discharges was to people living on houseboats (external exposure only) near Barrow in Cumbria).
Year Dose from external exposure, mSv y-1 Dose from ingestion and inhalation of radionuclides, mSv y-1 Total, mSv y-1
2013 0.076 0 0.076
2014 0.017 0.052 0.068
2015 0.017 0.061 0.078
2016 0.019 0.055 0.074
2017 0.016 0.061 0.077
2018 0.0043 0.030 0.034
2019 0.018 0.037 0.055
2020 0.015 0.044 0.058
2021 0.0027 0.016 0.019
2022 0.0027 0.011 0.014
2023 0.012 0.0075 0.019
2024 0.0088 0.0096 0.018
Figure 3.8. Radionuclide contributions from the ingestion and inhalation of radionuclides from nuclear industry to ‘total dose’, in mSv y-1, from all sources along the Cumbrian Coast, 2013 to 2024 (The highest ‘total dose’ in 2013 due to Sellafield discharges was to people living on houseboats (external exposure only) near Barrow in Cumbria)
Year Doses from 129I, mSv y-1 Doses from 99Tc, mSv y-1 Doses from 137Cs, mSv y-1 Dose from Pu isotopes, mSv y-1 Dose from 241Am, mSv y-1 Doses from other artificial radionuclides, mSv y-1 Total, mSv y-1
2013 0 0 0 0 0 0 0
2014 0.0028 0.00068 0.0026 0.014 0.026 0.0059 0.052
2015 0.012 0.0012 0.0022 0.014 0.026 0.0063 0.061
2016 0.010 0.00097 0.0024 0.013 0.021 0.0071 0.055
2017 0.012 0.0012 0.0023 0.013 0.027 0.0055 0.061
2018 0.0088 0.00074 0.0019 0.0036 0.011 0.0036 0.030
2019 0.0054 0.00073 0.0012 0.010 0.017 0.0028 0.037
2020 0.0086 0.00072 0.0011 0.011 0.020 0.0030 0.044
2021 0.0042 0.00034 0.00044 0.0014 0.0087 0.0011 0.016
2022 0.0041 0.00026 0.00037 0.00083 0.0044 0.00096 0.011
2023 0.0029 0.00013 0.00041 0.00054 0.0029 0.00060 0.0075
2024 0.0027 0.000082 0.00021 0.00072 0.0051 0.00075 0.0096

Other age groups in the Cumbrian Coastal Community received less exposure than the adults ‘total dose’ of 0.20mSv in 2024 (10-year-old children: 0.11mSv; 1-year-old infants: 0.074mSv; prenatal children: 0.037mSv). The contributors to the other age groups are similar to those for the overall ‘total dose, except the ‘total dose’ to prenatal children, which is due to external exposure. The ‘total dose’ estimated for each age group may be compared with the average dose of approximately 2.2mSv to members of the UK population from exposure to natural radiation in the environment (UKHSA Radiation and you) and to the annual dose limit to members of the public of 1mSv.

3.3.1.2. ‘Total dose’ from all pathways and sources in the vicinity of the Sellafield site

The annual ‘total dose’ from all pathways and sources of radiation is assessed using consumption and occupancy data from the full habits survey of 2023 (Moore and others 2024a) and the yearly review of shellfish and fish consumption, and intertidal occupancy in 2024 (Moore, Clyne & Greenhill 2025). Calculations are performed for 4 age groups (adults, 10-year-old children, 1-year-old infants and prenatal children).

The highest total dose for a local high-rate seafood consumer was assessed to have been 0.19mSv in 2024, or approximately 19 per cent of the dose limit to members of the public (Table 3.16). This dose is broken down as follows:

  • 0.18mSv from historical discharges of naturally occurring radionuclides from the former phosphate processing plant at Whitehaven, a decrease from 0.21 mSv in 2023
  • 0.012mSv from discharges of artificial radionuclides (including external radiation) from Sellafield, a decrease from 0.019 mSv in 2023. 0.0002mSv of this was from sources of direct radiation from Sellafield (the ‘representative person’ only receives a portion of the annual direct radiation dose of 0.003mSv)

The representative person was an adult consuming crustacean shellfish at high rates who also consumed significant quantities of other seafood (fish). The decrease in ‘total dose’ in 2024 was mostly attributed to reduced polonium-210 concentrations in crab and lobster.

The most significant contributions were from crustacean consumption (97%), fish consumption (1%) and other pathways (<1%). The listed food groups are consumption pathways the other pathways include external exposure over sediment. The most important radionuclide was polonium-210 from historical discharges of naturally occurring radionuclides from the former phosphate processing plant (93%) with transuranic radionuclides (including plutonium-239+240 and americium-241) contributing approximately 3% of the dose.

The dose in 2024 from artificial radionuclides discharged by Sellafield (including external radiation) and from historical discharges of naturally occurring radionuclides (from the former phosphate processing plant at Whitehaven) contributed 0.012mSv and 0.18mSv, respectively. Data for naturally occurring radionuclides in fish and shellfish, and their variation in recent years, are discussed in Section 7.5.

The contribution to the ‘total dose’ of 0.012mSv in 2024 from artificial radionuclides (including external radiation) was higher, in comparison to that in 2023 (0.008mSv). This was mostly attributed to increased concentrations of americium-241 in lobsters and to a lesser extent the update of habits information, in particular the increase in consumption rates of crustacean species. The contributing radionuclides to the dose from artificial radionuclides from Sellafield in 2024 were mostly americium-241 (42%), iodine-129 (23%, based on results at the analytical limit of detection), other radionuclides (including carbon-14 and caesium-137) (9%) and plutonium radionuclides (6%). External exposure contributed 20% of the ‘total dose’ from artificial radionuclides (11% in 2023).

Other age groups received less exposure than the adults ‘total dose’ of 0.19mSv in 2024 (10-year-old children: 0.10mSv; 1-year-old infants: 0.067mSv; prenatal children: 0.034mSv). The contributors to the other age groups are similar to those for the overall ‘total dose, except the ‘total dose’ to prenatal children, which is due to external exposure. The ‘total dose’ estimated for each age group may be compared with the dose of approximately 2.2mSv to members of the UK population from exposure to natural radiation in the environment (UKHSA Radiation and you) and to the annual dose limit to members of the public of 1mSv.

3.3.1.3. ‘Total dose’ from gaseous discharges and direct radiation in the vicinity of the Sellafield site

The annual ‘total dose’ from pathways related to gaseous discharges and sources of direct radiation is assessed by determining the highest dose to these pathways. Once the representative person has been identified, the contributions from all other pathways are then included.

Therefore, the representative person for the gaseous discharge pathway may also receive a dose contribution from consumption of seafood and intertidal occupancy.

The highest total dose from pathways related to gaseous discharges and sources of direct radiation in the vicinity of Sellafield was assessed to have been 0.046 mSv in 2024, or approximately 5% of the dose limit to members of the public (Table 3.16). This is made up of:

  • 0.036mSv from discharges of artificial radionuclides (including external radiation) from Sellafield, an increase from 0.033 mSv in 2023. 0.003mSv of this was from sources of direct radiation from Sellafield
  • 0.009mSv from historical discharges of naturally occurring radionuclides in seafood from the former phosphate processing plant, a decrease from 0.010 mSv in 2023

This is an increase from 0.043mSv in 2023. The most exposed profile and age group in 2024 was an adult who consumed freshwater fish, who also consumed sea fish and spent time over intertidal substrates and was unchanged from 2023. The profile selection is based upon which individual (derived from habits surveys) receives the highest dose from pathways related to the gaseous discharges and direct radiation from the Sellafield site. In this case, the habits of the freshwater fish consumers meant that they received the highest contributions from sources of direct radiation and consumption of root vegetables (containing americium-241). After selection all pathways are re-included in the assessment, including aquatic pathways (see Section 1.2.2). The increase in the ‘total dose’ was due to increased gamma dose rates at Whitehaven, St Bees, and Ravenglass boat area.

The pathway contributors in 2024 to the ‘total dose’ for adults were from external exposure over sediments (53%), consumption of sea water fish (35%), occupancy for direct radiation (7%) and consumption of root vegetables (3%).

3.3.1.4. ‘Total dose’ from liquid discharges in the vicinity of the Sellafield site

The people receiving the highest ‘total dose’ from the pathways predominantly relating to liquid discharges are given in Table 3.16. Each ‘total dose’ is the same as that giving their maximum ‘total dose’ for all sources and pathways.

3.3.1.5. Source specific doses

Doses from important routes of exposure resulting from radioactive waste discharges from Sellafield were estimated using source specific assessments, and the results of these are given in Table 3.15 and Table 3.16. As in recent years, the sources of highest potential exposure were high-rate consumption of seafood, and external exposure from gamma rays over long periods. Other pathways were kept under review, particularly the potential for sea to land transfer at the Ravenglass Estuary to the south of the site, exposure from contact with beta-emitting radionuclides during handling of sediments and/or handling of fishing gear and from gaseous discharges, and the high-rate consumption of locally grown food.

Doses from terrestrial food consumption

In 2024, infants (1-year-old) consuming milk at high rates and exposed to external and inhalation pathways from gaseous discharges received the highest dose for all ages. The estimated dose was 0.010mSv in 2024 (Table 3.16), or 1% of the dose limit to members of the public and down from 0.012mSv in 2023. Other age groups received less exposure than the infants dose of 0.010mSv in 2024 (adults: 0.007mSv; 10-year-old children: 0.007mSv; prenatal children: 0.005mSv).

Doses from seafood consumption

Two sets of habits data are used in these dose assessments. One is based on the habits information seen in the area each year (2024 habits survey). The second is based on a 5-year rolling average using habits data gathered from 2020 to 2024. Some changes were found in the amounts (and mixes) of species consumed compared to those in the 2024 and the 2020 to 2024 rolling average. For crustaceans (crab and lobster, and other crustaceans), the total consumption rate increased in the 2024 habits survey but decreased in the 2020 to 2024 rolling average data. For fish (cod, other fish), the total consumption rate increased in both the 2024 habits survey and in the 2020 to 2024 rolling average data. For molluscs (winkles and other molluscs), the total consumption rates increased in the 2024 habits and decreased in the 2020 to 2024 rolling average data. The occupancy rate over sediments decreased in both the 2024 habits information and the 2020 to 2024 rolling average. The revised habits data are given in Appendix 4 (Table A4.2).

Aquatic pathway habits are normally the most important in terms of dose near Sellafield and are surveyed every year (for example Moore, Clyne & Greenhill 2023). This allows generation of a unique yearly set of data and also rolling 5-year averages. The rolling averages are intended to smooth the effects of sudden changes in habits and provide an assessment of dose that follows more closely changes in radioactivity concentrations in food and the environment. These are used for the main assessment of doses from liquid discharges and follow the recommendations of the report of the consultative exercise on dose assessments (CEDA) (Food Standards Agency 2001).

Table 3.16 summarises source specific doses to seafood consumers in 2024. The doses from artificial radionuclides to people who consume a large amount of seafood were 0.030mSv (0.027mSv in 2023) and 0.040mSv (0.039mSv in 2023) using the annual and 5-year rolling average habits data, respectively. These doses each include a contribution due to external radiation exposure over sediments.

The dose to high-rate consumer of seafood, due to the naturally occurring radionuclides resulting from historical discharges from the former phosphate works near Whitehaven (using maximising assumptions for the dose coefficients and the 5-year rolling average habits data), is estimated to have been 0.27mSv in 2024, and down from 0.32mSv in 2023. Most of this was due to polonium-210 (92%). For comparison (with the assessment using the 5-year rolling average habits data), the dose from the single-year assessment for the Cumbrian coastal community seafood consumer from naturally occurring radionuclides (based on consumption rates and habits survey data in 2024) was 0.20mSv (Table 3.16).

Taking artificial and enhanced natural radionuclides together, the source specific doses were 0.23mSv and 0.31mSv for the annual and 5-year rolling average habits data, respectively. These estimates are slightly higher or similar than the estimate of ‘total dose’ from all sources of 0.20mSv. The main reason for this is a difference in the approach to selecting consumption rates for seafood for the representative person. The differences in dose are expected and are within the uncertainties in the assessments (see Section 2.13).

Exposures typical of the wider communities associated with fisheries in Whitehaven, Dumfries and Galloway, the Morecambe Bay area, Northern Ireland and North Wales have been kept under review in 2024 (Table 3.15). Those for fisheries in the Isle of Man and Fleetwood have been shown to be generally lower and dose data are available in earlier RIFE reports (for example Environment Agency, Food Standards Agency, Natural Resources Wales and others 2014). Where appropriate, the dose from consumption of seafood is summed with a contribution from external exposure over intertidal areas. The doses received in the wider communities were significantly lower than for the Cumbrian coastal community because of the lower concentrations and dose rates further afield. There were generally small changes in the doses (and contribution to doses) in each area in 2024 (Table 3.15), in comparison to those in 2023. For example, on the Dumfries and Galloway coast, the decrease in dose, in 2024, to 0.014mSv (from 0.021mSv in 2023) was mostly due to the revision of habits information (mollusc consumption rate). All annual doses of the wider communities were well within the dose limit for members of the public of 1mSv.

The dose to a person, who typically consumes 15kg of fish per year from landings at Whitehaven is also given in Table 3.16. This dose was less than 0.005mSv in 2024. The consumption rate used represents an average for a typical consumer of seafood from the north-east Irish Sea.

Doses from sediments

The main radiation exposure pathway associated with sediments is due to external dose from gamma-emitting radionuclides adsorbed on intertidal sediments in areas frequented by the public. This dose can make a significant contribution to the total exposure of members of the public in coastal communities of the north-east Irish Sea but particularly in Cumbria and Lancashire. Gamma dose rates currently observed in intertidal areas are mainly due to radiocaesium and naturally occurring radionuclides. For some people, the following pathways may also contribute to doses from sediments: exposure due to beta-emitting radionuclides during handling of sediments or fishing gear; inhalation of re-suspended beach sediments; and inadvertent ingestion of beach sediments. These pathways are considered later. In the main, they give rise to only minor doses compared with those due to external gamma-emitters.

Gamma radiation dose rates over areas of the Cumbrian coast and further afield in 2024 are given in Table 3.9. The results of the assessment of external exposure pathways are included in Table 3.16. The highest whole-body exposures due to external radiation resulting from Sellafield discharges, past and present, was received by a local houseboat dweller at Barrow, Cumbria. In 2024, the dose was 0.060mSv, or 6% of the dose limit, and up from 0.040mSv in 2023 (see Section 6.2). Other people received lower external doses in 2024. The dose to a person who spends a long time over the marsh in the Ravenglass Estuary was 0.016mSv in 2024, and an increase from that in 2023 (0.013mSv). This increase in dose was due to higher occupancy over salt marsh (Appendix 4, Table A4.2).

The doses to people in 2024 were also estimated for several other activities. Assessments were undertaken for a typical resident using local beaches for recreational purposes at 300 hours per year, and for a typical tourist visiting the coast of Cumbria with a beach occupancy of 30 hours per year. The exposure to residents was assessed for 2 different environments (at several locations) and at a distance from the Sellafield influence. The 2 different environments are 1) residents that visit and use beaches, and 2) residents that visit local muddy areas or salt marsh. Typical occupancy rates (Clyne and others 2008; Clyne and others 2010) are assumed and appropriate gamma dose rates have been used from Table 3.9. The activities for the typical tourist include consumption of local seafood and occupancy on beaches. Concentrations of radioactivity in fish and shellfish have been used from Table 3.5 to Table 3.7, and appropriate gamma dose rates used from Table 3.9. The consumption and occupancy rates for activities of a typical resident and tourist are provided in Appendix 4 (Table A4.2).

In 2024, the doses to people from recreational use of beaches varied from less than 0.005 to 0.009mSv (Table 3.16), with the higher doses being closer to the Sellafield source. The doses for recreational use of salt marsh and muddy areas had a similar variation, from less than 0.005 to 0.008mSv. The values for these activities were similar to those in recent years. The annual dose to a typical tourist visiting the coast of Cumbria, including a contribution from external exposure, was estimated to be less than 0.005mSv.

Doses from handling fishing gear and sediment

Exposures can also arise from contact with beta-emitting radionuclides during handling of sediments, or fishing gear on which fine particulates have become trapped. Habits surveys keep under review the amounts of time spent by fishers handling their fishing gear, and by bait diggers and shellfish collectors handling sediment. For those most exposed, the rates for handling nets and pots and for handling sediments are provided in Appendix 4 (Table A4.2). In 2024, the skin doses to a bait digger and shellfish collector from handling sediment was 0.11mSv (Table 3.16). This was less than 0.5% of the appropriate annual dose limit of 50mSv specifically for skin. The skin dose to a fisherman from handling fishing gear (including a component due to naturally occurring radiation), based on 2019 monitoring data was 0.14mSv. Therefore, both handling of fishing gear and sediments continued to be minor pathways of radiation exposure.

Doses from atmospheric sea to land transfer

At Ravenglass, the representative person was infants (1-year-old) from consuming terrestrial foods that were potentially affected by radionuclides transported to land by sea spray. In 2024, the dose (including contributions from Chernobyl and fallout from nuclear weapons testing) was estimated to be 0.014mSv, which was less than 2% of the dose limit for members of the public, and up from 0.013mSv in 2023. The increase in dose is attributed to higher limit of detection of ruthenium-106 in milk, in 2024, reflecting the variability in analytical performance rather than any changes in environmental concentrations. The largest contribution to the dose was, therefore, from ruthenium-106 in milk. As in previous years, sea-to-land transfer was not of radiological importance in the Ravenglass area.

Doses from seaweed and sea-washed pasture

Estimated annual doses for a high-rate consumer of laverbread (brown seaweed), and a high-rate consumer of vegetables (assuming these foods were obtained from the monitored plots near Sellafield and seaweeds were used as fertilisers and/or soil conditioners), are available in earlier RIFE reports (for example Environment Agency, Food Standards Agency, Natural Resources Wales and others 2014). Exposures of vegetable consumers using seaweed from further afield in Northern Ireland, Scotland and North Wales are expected to be much lower than near Sellafield.

Animals may also graze on seaweeds on beaches in coastal areas. However, there has been no evidence of this taking place significantly near Sellafield. A research study (relevant to the Scottish islands and coastal communities) conducted by UKHSA on behalf of the FSA and SEPA, investigated the potential transfer of radionuclides from seaweed to meat products and also to crops grown on land where seaweed had been applied as a soil conditioner (Brown and others 2009). The study concluded that the highest levels of dose to people using seaweed, as a soil conditioner or an animal feed, were in the range of a few microSieverts (µSv) and most of the doses are at least a factor of 100 lower. The report is available on SEPA’s website: SEPA environmental monitoring reports.

3.3.2. Gaseous discharges and monitoring

Permitted discharges to atmosphere are made from a wide range of facilities at the site including the fuel storage ponds, the reprocessing plants and waste treatment plants, as well as from Calder Hall Power Station. Discharges to atmosphere, during 2024 are summarised in Appendix 1 (Table A1.1). The permit limits gaseous discharges for gross alpha and beta activities, and 8 specified radionuclides. In addition to overall site limits, plant notification levels have been set on discharges from the main contributing plants on site.

Monitoring of terrestrial foods in the vicinity of Sellafield is conducted by the FSA to reflect the scale and risk of discharges from the site. This monitoring is the most extensive of that for the nuclear sites in the UK. A range of foodstuffs was sampled in 2024 including milk, fruit, vegetables, meat and offal, game, and environmental materials (grass and soil). Samples were obtained from different locations around the site to allow for variations due to the influence of meteorological conditions on the dispersal of gaseous discharges. The analyses conducted included gamma-ray spectrometry and specific measurements for tritium, carbon-14, strontium-90, technetium-99, iodine-129, uranium and transuranic radionuclides.

The results of monitoring in 2024 are given in Table 3.4. The activity concentrations of all radionuclides around the site were low. Activity concentrations in terrestrial foodstuffs were generally similar to those in recent years. Activity concentrations of radionuclides in meat and offal (cattle and sheep) were low, with many reported as below the limit of detection with only very limited evidence of the effects of Sellafield’s gaseous discharges, detected in concentrations of carbon-14 in meat and offal samples.

A range of foods (including fruit and vegetables) and terrestrial indicator materials was sampled in 2024, and the activity concentrations were generally similar to those found in previous years. In common with meat and offal samples, only limited evidence of the gaseous discharges from Sellafield was found in some of these foods. Strontium-90 was positively detected in a number of food samples (including milk) at low concentrations. As in 2023, the maximum iodine-129 and iodine-131 concentrations in milk were reported as below the limit of detection. Small enhancements (above the expected background) in concentrations of carbon-14 were found in some food samples (including milk), as in recent years. Concentrations of transuranic radionuclides, when detectable in these foods, were very low. Maximum concentrations of radionuclides in milk (near Sellafield), and corresponding discharges of carbon-14, strontium-90 and caesium-137, for more than a decade are shown in Figure 3.9. Over the whole period, concentrations of carbon-14 were relatively constant (with some variation between years and close to background), and caesium-137 concentrations (and strontium-90 to a lesser extent) were declining overall.

Figure 3.9(a). Concentrations of carbon-14 in milk, in Bq l-1, near Sellafield and gaseous discharges of carbon-14, in TBq y-1, from Sellafield, 2013 to 2024.
Figure 3.9(b). Concentrations of strontium-90 in milk, in Bq l-1, near Sellafield and gaseous discharges of strontium-90, in TBq y-1, from Sellafield, 2013 to 2024.
Figure 3.9(c). Concentrations of caesium-137 in milk, in Bq l-1, near Sellafield and gaseous discharges of caesium-137, in TBq y-1, from Sellafield, 2013 to 2024.

3.3.3. Liquid discharges and monitoring

Permitted liquid discharges derive from a variety of sources at the site including the fuel storage ponds, the reprocessing plants, from the retrieval and treatment of legacy wastes, the laundry and general site drainage. Wastes from these sources are treated and then discharged to the Irish Sea via the sea pipelines that terminate 2.1km beyond low water mark. A small quantity of low activity liquid wastes (mostly rainfall runoff) are also discharged from the factory sewer to the River Ehen Estuary and (since 2015) some liquid wastes are also discharged via the Calder Interceptor Sewer (Environment Agency, Food Standards Agency, Scotland, snd others 2016). Discharges from the Sellafield pipelines during 2024 are summarised in Appendix 1 (Table A1.2). The current permit sets limits on gross alpha and beta, and 12 individual radionuclides. In addition to overall site limits, plant notification levels have been set on discharges from the main contributing plants on site (Segregated Effluent Treatment Plant, Site Ion Exchange Effluent Plant (SIXEP), Enhanced Actinide Removal Plant and THORP).

All discharges of liquid wastes from Sellafield were less than the permit limits in 2024. Liquid discharges of the majority of radionuclides decreased, in 2024, compared to releases in 2023.

The downward trend of technetium-99 discharges from Sellafield is given in Figure 3.10 (2013 to 2024) and Figure 3.11 (1995 to 2024). Technetium-99 discharges have substantially reduced from the peak of 192TBq in 1995. Further information relating to past discharges of technetium-99 is available in earlier RIFE reports (for example (Environment Agency, Food Standards Agency, Food Standards Scotland, Natural Resources Wales and others 2019)).

Figure 3.10(a). Technetium-99 in Sellafield seaweed (‘Fucus vesiculosus’), in Bq kg-1 (fresh), and Sellafield discharges, in TBq y-1, 2013 to 2024.
Figure 3.10(b). Technetium-99 in Dounreay seaweed (‘Fucus vesiculosus’), in Bq kg-1 (fresh), 2013 to 2024.
Figure 3.10(c). Technetium-99 in Hartlepool seaweed (‘Fucus vesiculosus’), in Bq kg-1 (fresh), 2013 to 2024.
Figure 3.10(d). Technetium-99 in Bradwell seaweed (‘Fucus vesiculosus’), in Bq kg-1 (fresh), 2013 to 2024.
Figure 3.10(e). Technetium-99 in Dungeness seaweed (‘Fucus vesiculosus’), in Bq kg-1 (fresh), 2013 to 2024.
Figure 3.10(f). Technetium-99 in Isles of Scilly seaweed (‘Fucus vesiculosus’), in Bq kg-1 (fresh), 2013 to 2024.
Figure 3.10(g). Technetium-99 in Fishguard seaweed (‘Fucus vesiculosus’), in Bq kg-1 (fresh), 2013 to 2024.

Figure 3.10(h). Technetium-99 in Ardglass seaweed (‘Fucus vesiculosus’), in Bq kg-1 (fresh), 2013 to 2024.

Figure 3.10(i). Technetium-99 in Port William seaweed (‘Fucus vesiculosus’), in Bq kg-1 (fresh), 2013 to 2024.
Figure 3.11. Technetium-99 in UK seaweed (‘Fucus vesiculosus’), in Bq kg-1 (fresh), and Sellafield liquid discharges, in T Bq y-1, between, 1995 to 2024.
3.3.3.1. Monitoring of the marine environment

Regular monitoring of the marine environment near to Sellafield and further afield was conducted during 2024, by the Environment Agency and FSA (for England and Wales), NIEA (for Northern Ireland) and SEPA (for Scotland). In Scotland, SEPA and the FSS work closely together to maximise the value of every sample taken as it is fully funded by the Scottish Government. The monitoring locations for seafood, water, environmental materials and dose rates near the Sellafield site are shown in Figure 3.12 and Figure 3.13, the corresponding sample species, types and locations are listed in the corresponding site tables.

Figure 3.12. Monitoring locations in Cumbria, 2024 (not including farms).
Figure 3.13. Monitoring locations at Sellafield, 2024 (not including farms).
3.3.3.2. Monitoring of fish and shellfish

Concentrations of beta and gamma activity in fish from the Irish Sea and from further afield are given in Table 3.5. Data are listed by location of sampling or landing point, north to south in Cumbria, then in approximate order of increasing distance from Sellafield. Results are available for previous specific surveys in the ‘Sellafield Coastal Area’ (extending 15km to the north and to the south of Sellafield, from St Bees Head to Selker, and 11km offshore) and the smaller ‘Sellafield Offshore Area’ (consisting of a rectangle, 1.8km wide by 3.6km long, situated south of the pipelines) in earlier RIFE reports (for example, (Environment Agency, Food Standards Agency, Natural Resources Wales and others 2014)). Concentrations of specific naturally occurring radionuclides in fish and shellfish in the Sellafield area are given in Section 7.

The concentrations of most radionuclides have decreased over the previous decades in response to decreases in discharges (Environment Agency and others 2011). Concentrations generally continue to reflect changes in discharges over time periods, characteristic of radionuclide mobility and organism uptake. More recent trends in concentrations of radionuclides, and corresponding discharges, in seafood near Sellafield (over the last decade) are shown in Figure 3.14 to Figure 3.19. There was variability from year to year, particularly for the more mobile radionuclides. Over the period 2013 to 2024, discharges and the concentrations of carbon-14 in fish and shellfish have declined (Figure 3-15). Discharges of cobalt-60 have decreased over the period 2013 to 2024 (Figure 3-16), however concentrations in fish and shellfish have shown some variation year on year, albeit at low concentrations. Liquid discharges of technetium-99 and concentrations of technetium-99 in fish and shellfish in 2024 (Figure 3.16) were similar, in comparison to their respective values in recent years. Over a longer timescale, technetium-99 concentrations in fish and shellfish have shown a continued reduction, from the relatively elevated values in the previous decade (Environment Agency and others. 2011). For the transuranic elements (Figure 3.18 and Figure 3.19), the trend of reductions in concentrations is not evident, unlike in earlier decades (Environment Agency and others 2011). Over the last decade, discharges and concentrations of americium-241 and plutonium-239+240 in fish and shellfish have continued to show some variations from year to year (Figure 3.18 and Figure 3.19). Overall, these concentrations in shellfish have decreased over the period. The mean concentrations of carbon-14, cobalt-60, technetium-99, caesium-137, plutonium-239+240 and americium-241 in shellfish, were generally similar in 2024, compared to those in 2023.

Figure 3.14. Carbon-14 concentrations in plaice, lobsters and winkles, in Bq kg-1 (fresh), near Sellafield and liquid discharge from Sellafield, in Bq y-1 , 2013 to 2024.
Figure 3.15. Cobalt-60 concentrations in plaice (multiplied by 100), lobsters (multiplied by 10) and winkles near Sellafield, in Bq kg-1 (fresh), and liquid discharge from Sellafield, in Bq y-1 , 2013 to 2024.
Figure 3.16. Technetium-99 concentrations in plaice (multiplied by 100), lobsters and winkles (multiplied by 10), in Bq kg-1 (fresh), near Sellafield and liquid discharge from Sellafield, in Bq y-1 , 2013 to 2024.
Figure 3.17. Caesium-137 concentrations in plaice, lobsters and winkles, in Bq kg-1 (fresh), near Sellafield and liquid discharge from Sellafield, in Bq y-1 , 2013 to 2024.
Figure 3.18. Plutonium-239+240 concentrations in plaice (multiplied by 100), lobsters (multiplied by 100) and winkles, in Bq kg-1 (fresh), near Sellafield and liquid discharge from Sellafield, in Bq y-1 , 2013 to 2024.
Figure 3.19. Americium-241 concentrations in plaice (multiplied by 100), lobsters (multiplied by 10) and winkles , in Bq kg-1 (fresh), near Sellafield and liquid discharge from Sellafield, in Bq y-1 , 2013 to 2024.

Beta- and gamma-emitting radionuclides detected in fish included tritium, carbon-14, technetium-99 and caesium-137 (Table 3.5). Overall, concentrations of caesium-137 in fish species, across a wide range of sampling locations, were generally similar in 2024, compared to those in 2023. Over longer time, activity concentrations in fish and shellfish appear to be generally declining (with minor variations) at a slow rate (Figure 3.17). Activity concentrations in fish (and shellfish) generally reflected progressive dilution with increasing distance from Sellafield. However, the rate of decline of caesium-137 concentrations with distance was not as marked as was the case when significant reductions in discharges were achieved in earlier decades.

Other artificial beta- and gamma-emitting radionuclides detected in fish included carbon-14 and tritium (Table 3.5). With an expected carbon-14 concentration from natural sources of about 20Bq kg-1 (see Appendix 6, Table A6.1), the data suggest a continued local enhancement of carbon-14 due to discharges from Sellafield. In 2024, carbon-14 is reported as the highest activity concentration in marine fish (mix of cod and whiting, 41Bq kg-1) from Parton. In 2024, the majority of both tritium and organically bound tritium (OBT) values, across all species and locations, were reported as below the limit of detection, with a value just above the LoD reported in Morecambe Bay Flounder (35Bq kg-1).

For shellfish, a wide range of radionuclides is detectable, owing to generally greater uptake of radioactivity by these organisms from sediments. Generally, molluscs tend to contain higher concentrations than crustaceans and both contain higher concentrations than fish. Concentrations of beta- and gamma-emitting radionuclides are shown in Table 3.6 (Table 3.7 for plutonium-241). There can be substantial variations between species; for example, lobsters tend to concentrate more technetium-99 than crabs (as shown in references, (Knowles, Smith & Winpenny 1998; Swift & Nicholson 2001)). The highest concentrations in the marine environment from Sellafield discharges were carbon-14, tritium and technetium-99. Comparing 2023 and 2024 data across a wide range of sampling locations and shellfish species (where comparisons can be made), technetium-99 concentrations were similar (with minor variations) but reduced in comparison to those years prior to 2012 due to the progressive reductions in discharges of this radionuclide. Concentrations of other radionuclides (non-transuranic) in 2024 were also broadly similar (where comparisons can be made) to those in 2023.

Transuranic radionuclide data for fish and shellfish samples (chosen on the basis of potential radiological significance) in 2024 are given in Table 3.7. Transuranic elements are less mobile than other radionuclides in seawater and have a high affinity for sediments. This is reflected in higher concentrations of transuranic elements in shellfish compared with fish. Comparing 2024 and 2023 data across a wide range of sampling locations and shellfish species further afield from Sellafield, concentrations in shellfish were generally similar (where comparisons can be made). Those from the north-eastern Irish Sea were the highest transuranic concentrations found in foodstuffs in the UK. In 2024, the concentrations of plutonium and americium-241 in shellfish were generally lower (by small amounts) compared to those in 2023 at most of the north-eastern Irish Sea locations (for example, winkles from Parton). Americium-241 concentrations in mussels (near Sellafield) were also generally similar in 2024, compared to those in 2023. Overall, plutonium-239+240 and americium-241 concentrations in lobsters (near Sellafield) were generally lower (with minor variations) in 2024, compared to those in recent years. The concentrations of plutonium-239+240 and americium-241 in winkles (Nethertown) and lobster (Sellafield Coastal Area) in 2023 were the lowest reported values in recent years (Figure 3.18 and Figure 3.19). Variations of these observations in previous years were likely to have resulted from a combination of mechanisms including natural environmental variability and redistribution of sediments due to natural processes.

3.3.3.3. Monitoring of sediments

Radionuclides in Sellafield liquid discharges are taken up by sediments along the Cumbrian Coast, in particular in muddier (fine grained) areas such as estuaries. Some of these areas are used by the public. Concentrations of radionuclides are regularly monitored, both because of their relevance to exposure and to keep distributions of radioactivity under review. The results for 2024 are shown in Table 3.8. Radionuclides positively detected were manganese-54, cobalt-60, strontium-90, caesium-137, europium-155, and transuranic elements. The highest concentrations found are close to the site and in fine particulate materials in estuaries and harbours, rather than the coarser grained sands on open beaches. In 2024, the concentrations of caesium-137 and plutonium-238, plutonium-239+240 and americium-241 radionuclides were lower, whereas plutonium-241 was higher, in the River Mite Estuary (an erosional area), compared to those in 2023. The concentrations of long-lived radionuclides, particularly caesium-137 and the transuranic elements, largely reflect past discharges from Sellafield, which were considerably higher than in recent years. Over the last 4 decades, discharges have fallen significantly as the site provided enhanced treatment to remove radionuclides prior to discharge. Overall, concentrations in sediments were generally similar in 2024, compared to those in 2023.

The trends over time (1995 to 2024) for activity concentrations in mud from Ravenglass and liquid discharges from Sellafield are shown in Figure 3.20 to Figure 3.23. The concentrations of most radionuclides have declined over the time period in response to decreases in discharges, with sustained reductions in discharges of caesium-137 and transuranic elements. Discharges of cobalt-60 have been variable in the earlier years but reduced over the last decade, as reflected in the sediment concentrations at Ravenglass, with some evidence of a time lag between discharge and sediment concentration (Figure 3.22). In 2024, the reported cobalt-60 concentration in mud from Ravenglass (Newbiggin) is the lowest reported value in recent years. Over the last decade, caesium-137 and transuranic concentrations in sediments have remained relatively constant (Figure 3.20, Figure 3.21 and Figure 3.23). Since the mid-1990s, discharges of caesium-137, plutonium isotopes and americium-241 have remained low, but with some variability. There is a suggestion of small progressive increases in caesium-137 and transuranic elements activities in sediments (peaking in both 2006 and 2014). The likely explanation is that changes in these concentrations are due to remobilisation and subsequent accretion of fine-grained sediments containing higher activity concentrations. For americium-241, there is also a contribution due to radioactive in-growth from the parent plutonium-241 already present in the environment. The effect is less apparent in fish and shellfish (Figure 3.17 to Figure 3.19) and will continue to be monitored.

Figure 3.20. Caesium-137 concentration in mud, in Bq kg-1 (dry), at Ravenglass and liquid discharge, in TBq y-1, from Sellafield, 1995 to 2024.
Figure 3.21. Plutonium-239+240 concentration in mud, in Bq kg-1 (dry), at Ravenglass and plutonium-alpha liquid discharge from Sellafield, in TBq y-1, 1995 to 2024.
Figure 3.22. Cobalt-60 concentration in mud, in Bq kg-1 (dry), at Ravenglass and liquid discharge from Sellafield, in TBq y-1, 1995 to 2024.
Figure 3.23. Americium-241 concentration in mud, in Bq kg-1 (dry), at Ravenglass and liquid discharge from Sellafield, in TBq y-1, 1995 to 2024.

Concentrations of caesium-137 and americium-241 in sediments from coastal locations of the north-east Irish Sea, including locations on the Dumfries and Galloway coast, Cumbrian coastline, Flookburgh, River Ribble estuary and North Wales coast, are also shown in Figure 3.24. Concentrations of both radionuclides diminish with distance from Sellafield. Overall, concentrations in 2024 at a given location were generally similar to those in recent years, and any fluctuations were most likely due to the normal variability expected in the environment.

Figure 3.24(a). Americium-241 and caesium-137 concentration, in Bq kg-1, in coastal sediments at Innerwell, 2000 to 2024.
Figure 3.24(b). Americium-241 and caesium-137 concentration, in Bq kg-1, in coastal sediments at Carsluith, 2000 to 2024.
Figure 3.24(c). Americium-241 and caesium-137 concentration, in Bq kg-1, in coastal sediments at Newton Arlosh, 2000 to 2024.
Figure 3.24(d). Americium-241 and caesium-137 concentration, in Bq kg-1, in coastal sediments at Carleton Marsh, 2000 to 2024. Note different scale used this location.
Figure 3.24(e). Americium-241 and caesium-137 concentration in coastal sediments at Newbiggin/Eskmeals, 2000 to 2024. Note different scale used this location.
Figure 3.24(f). Americium-241 and caesium-137 concentration, in Bq kg-1, in coastal sediments at Flookburgh, 2000 to 2024.
Figure 3.24(g). Americium-241 and caesium-137 concentration, in Bq kg-1, in coastal sediments at River Ribble Outfall, 2000 to 2024.
Figure 3.24(h). Americium-241 and caesium-137 concentration, in Bq kg-1, in coastal sediments at Caerhun, 2000 to 2024.
3.3.3.4. Monitoring of dose rates

Dose rates are regularly monitored at many locations, both in the Sellafield vicinity and further afield, using environmental radiation dosimeters. Table 3.9 provides the locations monitored by the environment agencies and the gamma dose rates in air at 1 metre above ground. Where comparisons can be made from similar ground types and locations, dose rates over intertidal areas throughout the Irish Sea in 2024 were generally similar to those in recent years (with small variations compared to those in 2023). Any variations between years are likely to have been due to normal variability expected in the environment. As in previous years, gamma dose rates were measured on the banks of the River Calder, which flows through the Sellafield site. In 2024, gamma dose rates did not show a significant excess above natural background downstream of the site. Although these dose rates have been locally enhanced in previous years on the banks of the River Calder, occupancy by the public (mainly anglers) is low in this area, this is unlikely to be more than a few tens of hours per year. On this basis, the resulting doses (in previous years) were also much less than those at other intertidal areas as discussed earlier in this section.

Gamma dose rates above mud and salt marshes, from a range of coastal locations in the vicinity of Sellafield, are shown in Figure 3.25 (2013 to 2024). Gamma dose rates at sandy locations are generally lower than those above mud or salt marshes. The general decrease in dose rates with increasing distance from Sellafield, which was apparent under conditions of higher discharges several decades ago, is no longer so prominent in recent years. Spatial variability of dose rates is expected, depending on ground type, with generally higher dose rates recorded over areas with finely grained sediments. For each location, there has been variation over time. Close to Sellafield (at Carleton Marsh and Newbiggin), there is some evidence to suggest that dose rates were slowly declining over time. Locations that are further afield from Sellafield show dose rate values that only marginally exceed average UK natural background rates.

Figure 3.25(a). Gamma dose rates, in microGy h-1, above fine coastal sediments (mud and salt marshes) at Innerwell, 2013 to 2024.
Figure 3.25(b). Gamma dose rates, in microGy h-1, above fine coastal sediments (mud and salt marshes) at Carsluith, 2013 to 2024.
Figure 3.25(c). Gamma dose rates, in microGy h-1, above fine coastal sediments (mud and salt marshes) at Newton Arlosh, 2013 to 2024.
Figure 3.25(d). Gamma dose rates, in microGy h-1, above fine coastal sediments (mud and salt marshes) at Carleton Marsh, 2013 to 2024.
Figure 3.25(e). Gamma dose rates, in microGy h-1, above fine coastal sediments (mud and salt marshes) at Newbiggin/Eskmeals, 2013 to 2024.
Figure 3.25(f). Gamma dose rates, in microGy h-1, above fine coastal sediments (mud and salt marshes) at Flookburgh, 2013 to 2024.
Figure 3.25(g). Gamma dose rates, in microGy h-1, above fine coastal sediments (mud and salt marshes) at River Ribble Outfall, 2013 to 2024.
Figure 3.25(h). Gamma dose rates, in microGy h-1, above fine coastal sediments (mud and salt marshes) at Caerhun, 2013 to 2024.

Over the last 4 decades, concentrations of radioactivity in the environment around Sellafield have declined as a result of reduced discharges. In more recent years, the values in the Esk Estuary have shown a less clear trend, with concentrations of some radionuclides fluctuating from year to year (for example, see Figure 3.21). This effect could be due to the dynamic nature of the sediment in the estuary, which is eroded and transported by tide and freshwater, periodically exposing older sediment (from depth) containing radioactivity from historical discharges. Due to annual variations and local concerns, the Environment Agency initiated a more detailed study of dose rates in the Esk Estuary in 2007. Further information providing more background information, and describing the objectives and results of this study, is available in earlier RIFE reports (for example Environment Agency and others 2015).

3.3.3.5. Monitoring of fishing gear

During immersion in seawater, fishing gear may trap particles of sediment on which radioactivity is adsorbed. Fishers handling this gear may be exposed to external radiation, mainly to skin from beta particles. Up to 2019, fishing gear was regularly monitored using surface contamination monitors. As in recent years, no monitoring of fishing gear was performed in 2024. Results up to 2019 are included in previous RIFE reports (for example, Environment Agency and others 2020).

3.3.3.6. Contact dose-rate monitoring of intertidal areas

Results from measurements of beta dose rates on shoreline sediments (using contamination monitors), to allow estimation of exposure of people who handle sediments regularly, are given in Table 3.10. Overall, positively detected dose rates in 2024 were generally similar to those in 2023 (where comparisons can be made from similar ground types and locations). Beta dose rates in sand were lower at St Bees compared to those in 2023. However, reported beta dose rates are low, with no radiological significance.

In 2008, the Environment Agency published a formal programme of work for the assessment of contamination by radioactive particles and objects[footnote 8] on and around the west Cumbrian coastline. The assessment was focused on public protection from high activity discrete radioactive particles that have been released to the environment from activities at the Sellafield site (Environment Agency 2008).

Beach survey work using vehicle mounted detectors, by the Sellafield site operator’s contractors, began in 2006. The current detection system in use is the Groundhog™ Synergy2 system, which was introduced in mid-2014 and was designed, and introduced, to further improve detection of americium-241 and strontium-90/yttrium-90. This replaced the Groundhog™ Synergy system, which was used from mid-2009 to mid-2014, which had a specific capability in relation to the detection of medium and high energy gamma-emitting radionuclides. The Groundhog™ Synergy system also provided improved detection capability for low energy gamma emissions (in comparison to the original system introduced in 2006), increasing the ability to detect particles containing americium-241.

Further beach monitoring for the 2024 calendar year was completed in line with the Environment Agency’s specification (Sellafield Limited 2025). During 2024, a total area of 118 hectares of the beaches along the Cumbrian coast were surveyed against a programme target of 105 hectares. A total of 42 particles and 9 larger objects were detected, recovered and analysed. The number of radioactive finds identified was 51 in 2024, of which approximately 82% were classified as particles (less than 2mm in size) and the remainder as larger objects. The number of finds were typical of those in recent years (for a summary of finds, see Sellafield beach monitoring. Most of the finds were concentrated on a 5km stretch of beach running northwest from the Sellafield site. All have been removed from the beaches. In 2024, none of the finds detected exceeded the characterisation triggers set within the Environment Agency’s intervention trigger levels: Sellafield radioactive objects intervention plan.

Monitoring along the Cumbrian coast will continue in 2025, with the current proposal being a further 105 hectares to be surveyed.

In 2012, UKHSA reported their review of the results and position on risk following the introduction of the improved monitoring (Groundhog™ Synergy system). The report concluded that the increase in particle finds following the introduction of this system was a result of its improved capability and also that advice previously given by UKHSA to the Environment Agency following a detailed assessment of risks in 2010 remained valid (Brown & Etherington 2011; Etherington and others 2012). The report restated the conclusion that, based on the currently available information, the overall health risks to beach users are very low and significantly lower than other risks people accept when using the beaches. As such, UKHSA advice remained that no special precautionary actions were required to limit access to or use of the beaches. A report by UKHSA describes the assessed health risks from the consumption of seafood (including those to commercial fishers) from radioactive particles in the vicinity of the Sellafield Site (Oatway & Brown 2015). Based on currently available information, it is concluded that the overall health risks to both seafood consumers and commercial fishers are very low. More recently, UKHSA were requested by the Environment Agency to update their recommendations, if supported by available evidence. This is to account for the information from the beach monitoring programme and from the further analysis of finds that have been collected since 2012. A summary report of assessing the risk to people’s health from radioactive objects on beaches around the Sellafield site was published by UKHSA in February 2020, concluding that the risk is very low (Oatway and others 2020).

In relation to food safety (and following a previous assessment of the particles frequency and the activity concentrations), FSA’s guidance to the Environment Agency supported UKHSA’s advice. The Environment Agency will continue to work with relevant authorities to keep the situation under review.

In 2007, SEPA published a strategy document for the assessment of the potential impact of Sellafield radioactive particles on members of the public in south-west Scotland (Scottish Environment Protection Agency 2007) and the beach monitoring programme was temporarily extended to include 2 locations on the north Solway coastline (Kirkcudbright Bay and Southerness). This was based on some limited modelling work on the movement of particles undertaken for the Environment Agency following a request by SEPA. No particles were detected at these locations. SEPA is maintaining a watching brief on the situation in as much as it may affect Scotland.

Further detail on enhanced beach monitoring data compiled so far can be obtained on the UK government website: Sellafield radioactive objects intervention plan - monitoring beaches near sellafield.

3.3.3.7. Monitoring of seaweed

Seaweeds are useful indicator materials, in addition to their occasional use in foods and as fertilisers. Seaweeds have the capability to readily accumulate radionuclides and thereby assist in the detection of these radionuclides in the environment. Table 3.11 gives the results of measurements in 2024 of seaweeds from shorelines of the Cumbrian coast and further afield. Comparing 2023 and 2024 data across a wide range of sampling locations, radionuclide concentrations were generally similar (where comparisons can be made) in seaweeds.

Fucus species of seaweeds are particularly useful indicators of most fission product radionuclides. In particular, samples of ‘Fucus vesiculosus’ are collected both in the Sellafield vicinity and further afield to show the extent of Sellafield contamination in north European waters. The effects of technetium-99 discharges from Sellafield on concentrations in seaweed are shown in Figure 3.10 (2013 to 2024) and Figure 3.11 (1995 to 2024). In the north-east Irish Sea, technetium-99 concentrations have been reasonably constant over the present decade, consistent with the relatively low discharges; the highest concentrations which were found near Sellafield were much less than those in the mid-1990s and the decade thereafter (in response to the progressive reduction in discharges). In general, there was also a large reduction in concentrations of technetium-99 in ‘Fucus vesiculosus’ with distance from Sellafield, as the effect of the discharges becomes diluted in moving further afield.

Technetium-99 concentrations in seaweed (Table 3.11) collected from sites in Cumbria were generally lower by small amounts in 2024, compared to those in 2023. Over the last 5 years, small variations have been found, year on year, but technetium-99 concentrations in seaweed in 2024 were still low (Figure 3.10). At one specific location (Auchencairn, Scotland), known to have had fluctuating concentrations in previous years, technetium-99 concentrations in seaweed (Fucus) were lower in 2024 compared with those in 2023. The reasons behind these variations have been described in previous RIFE reports (for example (Environment Agency, Food Standards Agency, Food Standards Scotland, Natural Resources Wales and others 2019)).

3.3.3.8. Monitoring of tide-washed pasture

The potential transfer of technetium-99 to milk, meat and offal from animals grazing tide-washed pasture was considered using a modelling approach in the report for 1997 (Ministry of Agriculture Fisheries and Food & Scottish Environment Protection Agency 1998). The maximum potential dose was calculated to be 0.009mSv per year, at that time. Follow-up sampling of tide-washed pastures at Newton Arlosh (Cumbria) and Hutton Marsh (Lancashire) in 2006 suggested that this dose estimate remains valid (Environment Agency and others 2007).

3.3.3.9. Monitoring of sea to land transfer

Terrestrial foodstuffs are monitored near Ravenglass to check on the extent of transfer of radionuclides from sea to land in this area. In 2024, samples of milk and livestock were collected and analysed, for radionuclides which were released in liquid effluent discharges from Sellafield. Results from surveys for activity concentrations in crops, fruit and environmental indicators are available in earlier RIFE reports (for example, Environment Agency, Food Standards Agency, Natural Resources Wales and others 2014).

The results of measurements in 2024 are given in Table 3.12. Generally, the activity concentrations, where positively detected, show lower concentrations than were found in the immediate vicinity of Sellafield (Table 3.4). As in previous years, the evidence for sea to land transfer was very limited in 2024. Technetium-99 concentrations are reported as below (or close) to the limit of detection. Small concentrations of artificial nuclides were detected in some samples, but the concentrations were very low. As in recent years, where detectable, observed isotopic ratios of plutonium-238 to plutonium-239+240 concentrations were somewhat higher than 0.025, a ratio which might be expected if the source was entirely due to fallout from nuclear weapons testing. This may suggest a Sellafield influence.

3.3.3.10. Monitoring of fishmeal

A theoretical study has established that any indirect onward transmission of both naturally occurring and artificial radioactivity into the human diet from the fishmeal pathway (that is fed to farmed fish, poultry, pigs, cows and sheep) is unlikely to be of radiological significance (Smith & Jeffs 1999). A detailed survey was undertaken to confirm these findings (Food Standards Agency 2003). Samples, obtained from 14 fish farms in Scotland and 3 in Northern Ireland, contained very low radionuclide concentrations, most being less than the limits of detection, and the few positively detected values were all less than 1Bq kg-1. Annually reported RIFE results for activity concentrations in farmed salmon from the west of Scotland confirm the findings of the FSA study (for example, Tables 2.5 and 2.7 (Environment Agency, Food Standards Agency, Natural Resources Wales and others 2014)).

3.3.3.11. Monitoring of waters

Evidence of the effects of liquid discharges from Sellafield on concentrations of radionuclides in seawater is determined by sampling from research vessels and the shore. The results of the seawater programme are given in Section 8.

Sampling of freshwater from rivers and lakes in west Cumbria is conducted as part of the regular environmental monitoring programme around Sellafield. However, other environmental materials are likely to be more indicative of direct site-related effects. Some of the sources monitored provide public drinking water. The results for 2024 are included in Table 3.13. Tritium, gross alpha and gross beta concentrations in public supplies were below the investigation levels for drinking water in the Water Supply (Water Quality) (Amendment) 2018 Regulations (retained from the European Directive 2013/51).

Small amounts of radioactivity are discharged from Sellafield under permit via the factory sewer outfall to the River Ehen Estuary, immediately prior to the confluence with the River Calder. In 2024, there was no evidence of tritium downstream or upstream of the outfall (Table 3.13). These are not drinkable waters, and any low concentrations observed previously are of no radiological significance. Table 3.13 also includes the results of monitoring from Ehen Spit beach (Figure 3.12) near Sellafield where water issues from the ground at low tide. This release is not due to permitted discharges of liquid wastes but to ground water migration from the Sellafield site. The water contains high levels of salt so it will not be used as a drinking water source and therefore the only consumption would be inadvertent (incidental). Enhanced gross beta and tritium concentrations were observed in 2024 with concentrations similar to those in recent years. The annual dose from inadvertent consumption of water from Ehen Spit has been shown to be insignificant (Environment Agency 2002).

3.3.3.12. Monitoring of unusual pathways

In 1998, high caesium-137 concentrations (up to 110,000Bq kg-1) were found in feral pigeons sampled in Seascale by the Ministry for Agriculture, Fisheries & Food (Ministry of Agriculture Fisheries and Food & Scottish Environment Protection Agency 1999). Further background information, describing the consequences of this monitoring, and remedial measures taken by the site operator, is available in earlier RIFE reports (for example Environment Agency and others 2015). Results of the analysis of a wild wood pigeon sample collected in 2024 are included in Table 3.4.The maximum caesium-137 concentration in the muscle of wood pigeon was reported just above the limit of detection (2.7Bq kg-1). These caesium-137 concentrations fluctuated in value prior to 2011, but elevated concentrations have not been sustained thereafter. Concentrations of artificial radionuclides were low and would add little to the exposure of local consumers. The FSA will continue to monitor this pathway.

Following discovery of elevated concentrations in feral pigeons, the Environment Agency began to sample and analyse sediments from road drains (gully pots) in Seascale and Whitehaven in 1999. Gully pots in road drains collect sediments washed off road surfaces and provide good indicators of radiological contamination of urban environments. The results of analyses in 2024 are shown in Table 3.14. Overall, activity concentrations are generally similar to those in recent years, although plutonium-239+240 and americium-241 concentrations decreased, by small amounts, in 2024. Further information of the previously elevated concentrations (of strontium-90, caesium-137, americium-241 and plutonium radionuclides) in road drain sediments is given in earlier RIFE reports (for example Environment Agency, Food Standards Agency, Food Standards Scotland, Natural Resources Wales and others 2019).

4. Nuclear power stations

Highlights

  • ‘total dose’ for the representative person was less than 2% of the dose limit for all sites assessed

England

Berkeley, Gloucestershire and Oldbury, South Gloucestershire
  • ‘total dose’ for the representative person was less than 0.005mSv and unchanged in 2024
Bradwell, Essex
  • ‘total dose’ for the representative person was less than 0.005mSv and unchanged in 2024
Dungeness, Kent
  • ‘total dose’ for the representative person was 0.010mSv and increased in 2024 compared to 2023
  • liquid discharges of sulphur-35 from Dungeness B were reported as nil in 2024
Hartlepool, County Durham
  • ‘total dose’ for the representative person was 0.007mSv and decreased in 2024 compared to 2023
  • liquid discharges of tritium decreased in 2024 compared to 2023
Heysham, Lancashire

  • ‘total dose’ for the representative person was 0.016mSv and increased in 2024 compared to 2023

  • gaseous discharges of carbon-14 from Heysham 1 and carbon-14 and sulphur-35 from Heysham 2 decreased in 2024 compared to 2023

Hinkley Point, Somerset
  • ‘total dose’ for the representative person was 0.014mSv and decreased in 2024 compared to 2023
  • liquid discharges of tritium and caesium-137 from Hinkley Point A and tritium from Hinkley Point B decreased in 2024 compared to 2023
Sizewell, Suffolk
  • ‘total dose’ for the representative person was 0.014mSv and increased in 2024 compared to 2023
  • gaseous discharges of carbon-14 from Sizewell B increased in 2024 compared to 2023
  • liquid discharges of tritium from Sizewell B increased in 2024 compared to 2023

Scotland

Chapelcross, Dumfries and Galloway
  • ‘total dose’ for the representative person was 0.007mSv and decreased in 2024 compared to 2023
Hunterston, North Ayrshire
  • ‘total dose’ for the representative person was 0.006mSv and decreased in 2024 compared to 2023
  • gaseous discharges of all other radionuclides (excluding tritium and carbon-14) from Hunterston A increased in 2024 compared to 2023
Torness, East Lothian
  • ‘total dose’ for the representative person was 0.011mSv and increased in 2024 compared to 2023

Wales

Trawsfynydd, Gwynedd
  • ‘total dose’ for the representative person was 0.010mSv and increased in 2024 compared to 2023
Wylfa, Isle of Anglesey
  • ‘total dose’ for the representative person was 0.008mSv and increased in 2024 compared to 2023

This section considers the results of environment and food monitoring, under the responsibility of the Environment Agency, FSA, FSS, NRW and SEPA, undertaken near nuclear power stations (both operating stations and stations being decommissioned). There is a total of 18 nuclear power stations (which may contain more than 1 reactor and reactor type) at 13 locations in the UK as listed in the highlights section above.

Ten of the 18 nuclear power stations are older, first generation power stations (Magnox reactors), owned by the NDA. The NDA was set up under the Energy Act 2004 and is a non-departmental public body (sponsored and funded by DESNZ). Its remit is to secure the decommissioning and clean-up of the UK’s civil public sector nuclear sites. All first generation stations are now in the process of decommissioning, including Calder Hall which is operated by Sellafield Limited (see Section 3). The remaining first generation stations are operated by NRS Limited (formerly Magnox Limited).

All first-generation nuclear reactors have now been completely defueled. In June 2025, the NDA published its annual business plan (April 2025 to March 2028) and a new strategy. The plan summarises the programme of work at each of the sites (Nuclear Decommissioning Agency 2025).

Seven AGR power stations and one PWR power station are owned and operated by EDF Energy Nuclear Generation Limited. These are: Dungeness B, Hartlepool, Heysham 1 and 2, Hinkley Point B, Sizewell B Power Stations in England, and Hunterston B and Torness Power Stations in Scotland. In 2021, EDF decided to move Dungeness B into defueling phase following an extended outage in the previous years. In June 2021, the UK government and EDF signed an agreement to transfer control of the AGR power stations to the NDA after cessation of generation and defueling of the reactors. Hinkley Point B stopped generating electricity in 2022 and is being defueled. Hunterston B also stopped generating electricity in 2022 and defueling was completed in 2025. The decommissioning process of these 2 plants will be carried out by NRS after Fuel Free Verification is achieved by EDF at Hinkley Point B and Hunterston B.

Gaseous and liquid discharges from each of the power stations are regulated by the Environment Agency and NRW in England and Wales, respectively and by SEPA in Scotland. In 2024, gaseous and liquid discharges were below regulated limits for each of the power stations (see Appendix 1, Table A1.1 and Table A1.2). Solid waste transfers in 2024 from nuclear establishments in Scotland (Chapelcross, Hunterston A, Hunterston B and Torness) are also given in Appendix 1 (Table A1.4). Independent monitoring of the environment around each of the power stations is conducted by the FSA and the Environment Agency in England and Wales, and by SEPA in Scotland. The Environment Agency undertake the monitoring in Wales on behalf of NRW and the Welsh Government.

Data tables and the detailed results of the dose assessments, in Open Document Spreadsheet (ODS) format, are downloadable from the main RIFE page.

4.1. England

4.1.1 Berkeley, Gloucestershire and Oldbury, South Gloucestershire

Berkeley and Oldbury are both first generation nuclear power stations. Berkeley Power Station is situated on the eastern bank of the River Severn and was powered by 2 Magnox reactors. Berkeley was the first commercial power station in the UK to enter decommissioning. Electricity generation started in 1962 and ceased in 1989. De-fuelling was completed in 1992. Decommissioning is still in progress and small amounts of radioactive wastes are still generated by these operations. Recently, a modular encapsulation plant went into service to treat intermediate level waste (ILW) to make it suitable for longer term storage and eventual disposal. Berkeley also has an Advanced Vacuum Drying System (AVDS). The RSR permit was varied in December 2021 to increase site discharges limits to support the installation of this facility. This is used to dry legacy sludges and is an alternative to the modular encapsulation facility.

Oldbury Power Station is located on the south bank of the River Severn close to the village of Oldbury-on-Severn and has 2 Magnox reactors. Electricity generation started in 1967 and ceased in 2012. De-fuelling was completed in 2016, and the site is now prioritising the retrieval, treatment, and storage of ILW.

Berkeley and Oldbury sites are considered together for the purposes of environmental monitoring because the discharge effects from both sites impact on the same area. The most recent habits survey was undertaken in 2014 (Clyne, Garrod & Papworth 2015).

4.1.1.1. Doses to the public

In 2024, the ‘total dose’ from all pathways and sources of radiation was less than 0.005mSv (Table 4.1), or less than 0.5% of the dose limit to members of the public. This is unchanged from recent years. The representative person was an adult spending time over sediments, unchanged from 2023. The trend in the ‘total dose’ over the period 2013 to 2024 is given in Figure 4.1. Any longer-term variations in ‘total dose’ over time are attributable to changes in the contribution from direct radiation.

Figure 4.1. ‘Total dose’, in mSv y-1, at Berkeley and Oldbury nuclear power stations, 2013 to 2024. (Small doses less than or equal to 0.005mSv are recorded as being 0.005mSv).
Year Dose, mSv y-1
Dose limit 1.0
2013 0.010
2014 0.005
2015 0.005
2016 0.006
2017 0.005
2018 0.005
2019 0.005
2020 0.005
2021 0.013
2022 0.005
2023 0.005
2024 0.005

As in recent years, the source specific assessments for a high-rate consumer of fish and shellfish, in the vicinity of the Berkeley and Oldbury sites, gave exposures that were less than 0.005mSv in 2024 (Table 4.1). The dose to a consumer of fish and shellfish includes external gamma radiation and a component due to the tritium historically discharged from the Maynard Centre, the former GE Healthcare Limited plant at Cardiff[footnote 9]. As in 2023, the estimated dose for a high-rate consumer (infant) of locally grown foods gave an exposure of less than 0.005mSv in 2024.

The estimated dose for houseboat dwellers was 0.027mSv in 2024. This a decrease from 0.041mSv in 2023 because the average gamma dose rates recorded at Sharpness (over mud and over mud and salt marsh) were lower in 2024, compared to the average dose rate over a different substrate (salt marsh) in 2023. The estimate for this pathway is determined as a cautious value (and therefore not included in the ‘total dose’ assessment), because gamma dose rate measurements used were not necessarily representative of the categories of ground type and houseboat location (as identified in the habits survey (Clyne and others 2015)).

4.1.1.2. Gaseous discharges and terrestrial monitoring

The Berkeley and Oldbury sites discharge gaseous radioactive wastes via separate stacks to the atmosphere. The focus of the terrestrial sampling was for the analyses of tritium, carbon-14 and sulphur-35 in milk and crops. Local freshwater samples were also analysed. Data for 2024 are given in Table 4.2(a). As in 2023, sulphur-35 was detected positively in barley in 2024. Carbon-14 concentrations in milk were slightly above the default value used to represent background (see Appendix 5) and remain consistent with previous year. Tritium, gross alpha and gross beta concentrations in surface water were below the investigation levels for drinking water in the Water Supply (Water Quality) (Amendment) 2018 Regulations (retained from the European Directive 2013/51).

4.1.1.3. Liquid waste discharges and aquatic monitoring

Liquid radioactive wastes are discharged to the Severn Estuary. Oldbury has ceased generation and was verified by the ONR as fuel free in 2016.

Analyses of seafood and marine indicator materials as well as measurements of external radiation were conducted over muddy intertidal areas. Data for 2024 are given in Table 4.2(a) and Table 4.2(b). Most of the artificial radioactivity detected was due to caesium-137, representing the combined effect of discharges from the sites, other nuclear establishments discharging into the Bristol Channel, fallout from nuclear weapons testing, and possibly a small Sellafield-derived component. In 2024, caesium-137 concentrations in sediment were slightly higher than those observed in previous years but remained very low (Figure 4.2). Very small concentrations of other radionuclides were detected but taken together, were of low radiological significance. Gamma dose rates were generally similar to those observed in 2023.

Figure 4.2. Caesium-137 concentration, in Bq kg-1 (dry), in marine sediments near Berkeley and Oldbury nuclear power stations between 2013 and 2024.
Year 137Cs concentration Bq Kg-1 (dry)
2013 20
2014 19
2015 22
2016 18
2017 16
2018 13
2019 16
2020 13
2021 12
2022 12
2023 10
2024 23

4.1.2. Bradwell, Essex

The Bradwell site is located on the south side of the Blackwater Estuary. This Magnox power station ceased electricity production in 2002 after 40 years of operation, and de-fuelling was completed in 2006. In 2018, Bradwell became the UK’s first Magnox site to reach the interim end-state of passive Care and Maintenance, following an accelerated decommissioning programme.

Following the cessation of intermediate level waste (fuel element debris) treatment at Bradwell, enhanced environmental monitoring was reverted to the baseline monitoring programme in 2018. The results of the enhanced monitoring programme (2015 to 2017) are described in earlier RIFE reports (for example Environment Agency, Food Standards Agency, Food Standards Scotland, Natural Resources Wales and others 2018).

The most recent habits survey was undertaken in 2015 (Clyne, Garrod & Ly 2016).

4.1.2.1. Doses to the public

The ‘total dose’ from all pathways and sources of radiation was less than 0.005mSv in 2024 (Table 4.1), or less than 0.5% of the dose limit for members of the public. This is unchanged from recent years. The representative person in 2024 was an adult living on a houseboat, also unchanged from recent years. The trend in ‘total dose’ over the period 2013 to 2024 is given in Figure 4.3. Any significant variations in ‘total dose’ over time were attributed to changes in the estimate of direct radiation.

Figure 4.3. ‘Total dose’, in mSv y-1, at Bradwell nuclear power station, 2013 to 2024. (Small doses less than or equal to 0.005mSv are recorded as being 0.005mSv).
Year Dose, mSv y-1
Dose limit 1.0
2013 0.005
2014 0.005
2015 0.017
2016 0.036
2017 0.011
2018 0.011
2019 0.005
2020 0.005
2021 0.006
2022 0.005
2023 0.005
2024 0.005

As in recent years, the doses to a high-rate consumer of fish and shellfish and a high-rate consumer of locally grown foods from source specific assessment were less than 0.005mSv in 2024.

4.1.2.2. Gaseous discharges and terrestrial monitoring

The power station is permitted to discharge gaseous wastes to the local environment via stacks to the atmosphere. Terrestrial sampling is similar to that for other power stations including analyses of milk and crop samples. Samples of freshwater are also taken from a coastal ditch. Data for 2024 are given in Table 4.3(a). Activity concentrations were low in terrestrial samples. As in 2023, carbon-14 was detected in locally produced milk at concentrations close to the expected background concentration. Strontium-90 was positively detected in one of the coastal ditch freshwater samples (turbine hall void) in 2024. The gross beta activities in water from the coastal ditch were lower than those reported in recent years but continued to be above the investigation levels for drinking water in the Water Supply (Water Quality) (Amendment) 2018 Regulations (retained from the European Directive 2013/51). However, the water in the ditches is not known to be used as a source of drinking water.

4.1.2.3. Liquid waste discharges and aquatic monitoring

Liquid wastes are discharged into the River Blackwater estuary. The source of this effluent is rainwater which is discharged to the estuary via the main drains pit at Bradwell site. The main drains pit is sampled at quarterly intervals. The site is also permitted to discharge non-radioactive effluent from the turbine hall voids to the main drains pit, and from there to the estuary. However, no effluent from this source was discharged in 2024. Effluent was last discharged to the estuary via Bradwell site’s active effluent system in 2017. This route has since been decommissioned and was removed from the site’s permit when the permit was varied in 2019.

Aquatic sampling was directed at the consumption of locally caught fish and shellfish and external exposure over intertidal sediments. Seaweeds were also analysed as an environmental indicator material. Data for 2024 are given in Table 4.3(a) and Table 4.3(b). Low concentrations of artificial radionuclides were detected in marine samples as a result of discharges from the station, discharges from Sellafield and fallout from nuclear weapons testing. Due to the low concentrations detected, it is generally difficult to attribute the results to a particular source. There has been an overall decline in caesium-137 concentrations in sediments over the last decade (Figure 4.4). The caesium-137 concentrations observed in sediment samples collected in 2024 were similar to those reported in 2023 and were amongst the lowest reported values in recent years. Gamma dose rates on beaches were difficult to distinguish from natural background and were generally similar to those observed in recent years.

Figure 4.4. Caesium-137 concentration, in Bq kg-1 (dry), in marine sediments near Bradwell nuclear power station between 2013 and 2024.
Year 137Cs concentration Bq Kg-1 (dry)
2013 8.0
2014 6.1
2015 6.2
2016 7.0
2017 6.7
2018 4.0
2019 3.9
2020 4.0
2021 3.2
2022 3.4
2023 3.2
2024 2.7

4.1.3. Dungeness, Kent

The Dungeness power stations are located on the south Kent coast, between Folkestone and Rye. There are 2 separate A and B nuclear power stations on neighbouring sites: Dungeness A was powered by 2 Magnox reactors and Dungeness B has twin AGRs. Discharges are made via separate and adjacent outfalls and stacks, but for the purposes of environmental monitoring these are considered together. Dungeness A ceased generating electricity in 2006. De-fuelling of both Magnox reactors was completed in 2012, and the site is currently undergoing decommissioning. In 2021, Dungeness B nuclear power station was moved into the defueling phase following over 2 years of outage. The most recent habits survey was conducted in 2019 (Greenhill and others 2020).

4.1.3.1. Doses to the public

In 2024, the ‘total dose’ from all pathways and sources of radiation was 0.010mSv (Table 4.1), which was 1% of the dose limit to members of the public of 1mSv. This is an increase from less than 0.005mSv in 2023. The increase in ‘total dose’ was mainly attributed to a higher gamma dose rate observed over sand at Rye Bay, compared to 2023. Consequently, the representative person has changed to an adult spending extensive time over sand and shingles in 2024 from an adult living near the site in previous years. The trend in ‘total dose’ over the period 2013 to 2024 is given in Figure 4.5. The annual ‘total dose’ ranged between less than 0.005 and 0.037mSv over this period and were dominated by direct radiation. Over a longer time-series, this dose has declined more significantly from the peak value of 0.63mSv, following the shutdown of the Magnox reactors in 2006 (Environment Agency, Food Standards Agency, Food Standards Scotland, Natural Resources Wales and others 2018).

Figure 4.5. ‘Total dose’, in mSv y-1, at Dungeness nuclear power stations, 2013 to 2024. (Small doses less than or equal to 0.005mSv are recorded as being 0.005mSv).
Year Dose, mSv y-1
Dose limit 1.0
2013 0.021
2014 0.021
2015 0.014
2016 0.021
2017 0.021
2018 0.022
2019 0.037
2020 0.012
2021 0.012
2022 0.011
2023 0.005
2024 0.010

As in recent years, the dose to a high-rate consumer of locally grown foods was estimated to be less than 0.005mSv and unchanged from recent years (Table 4.1). The dose to a local seafood consumer was estimated to be 0.011mSv in 2024, up from 0.005mSv in 2023. The main reason for the increase in dose was the same as that contributing to the ‘total dose’.

4.1.3.2. Gaseous discharges and terrestrial monitoring

Gaseous wastes are discharged via separate stacks to the local environment. The focus of the terrestrial sampling was the analyses of tritium, carbon-14 and sulphur-35 in milk and crops. The results of monitoring for 2024 are given in Table 4.4(a). Activity concentrations in many terrestrial foods are reported as less than values (or close to the less than value). As in 2023, sulphur-35 was positively detected in grass. Unlike in 2023, tritium was not positively detected in food (potato) in 2024. As in recent years, carbon-14 was also detected in locally produced milk at concentrations slightly above the default value used to represent. Tritium, gross alpha and gross beta concentrations in freshwater were below the investigation levels for drinking water in the Water Supply (Water Quality) (Amendment) 2018 Regulations (retained from the European Directive 2013/51) in 2024.

4.1.3.3. Liquid waste discharges and aquatic monitoring

Permitted discharges of radioactive liquid effluent from both power stations are made via separate outfalls to the English Channel. The draining of fuel ponds at Dungeness A was completed in 2019 and this removed the main source of aqueous waste discharges on site. Dungeness B entered the defueling phase in 2021. The liquid discharge of sulphur-35 was reported as nil in 2024, as sulphur-35 concentrations in treated aqueous effluent has now fallen below detectable limits following cessation of electricity generation. Marine monitoring included gamma dose rate measurements, and analysis of seafood, seaweed, sediments and seawater. The results of monitoring for 2024 are given in Table 4.4(a) and Table 4.4(b). The caesium-137 concentrations in seafood are attributable to discharges from the stations, fallout from nuclear weapons testing and a long-distance contribution from Sellafield and La Hague reprocessing facility in France. Due to the low concentrations detected in foods and marine materials, it is generally difficult to attribute the results to a particular source. The low concentrations of transuranic nuclides in molluscs (scallop sample collected in 2024) were typical of values expected at sites remote from Sellafield. As in recent years, the 2024 tritium results in seafood were all reported as less than values (or just above the less than value). Caesium-137 concentrations in sediment have remained low over the last decade (Figure 4.6). Caesium-137 was detected at a very low concentrations (reported as just above the less than value) in sediments from Rye Harbour, Camber Sands and Pilot Sands in 2024.

Figure 4.6. Caesium-137 concentration, in Bq kg-1 (dry), in marine sediments near Dungeness nuclear power stations between 2013 and 2024.
Year 137Cs concentration Bq Kg-1 (dry)
2013 0.35
2014 0.40
2015 0.46
2016 0.31
2017 0.24
2018 0.31
2019 0.28
2020 0.35
2021 0.30
2022 0.27
2023 0.56
2024 1.0

4.1.4. Hartlepool, County Durham

Hartlepool Power Station is situated on the mouth of the Tees Estuary, on the north-east coast of England. This station, which is powered by twin AGRs, began operation in 1983. The power station in Hartlepool is expected to end power production in 2027. The most recent habits survey was undertaken in 2024 (Moore, Clyne, Greenhill and others 2025).

4.1.4.1. Doses to the public

The ‘total dose’ from all pathways and sources of radiation was 0.007mSv in 2024 (Table 4.1), which was less than 1% of the dose limit to members of the public. This is a decrease from 0.015mSv in 2023. The decrease in ‘total dose’ was mainly attributed to revised habits data collected in 2024. The representative person was an adult living near the site, a change from 2023 (adult spending time over sediment). The trend in ‘total dose’ over the period 2013 to 2024 is given in Figure 4.7. The ‘total dose’ in 2024 was the lowest estimated in the last ten years.

Figure 4.7. ‘Total dose’, in mSv y-1, at Hartlepool nuclear power station, 2013 to 2024.
Year Dose, mSv y-1
Dose limit 1.0
2013 0.024
2014 0.027
2015 0.022
2016 0.020
2017 0.031
2018 0.012
2019 0.013
2020 0.017
2021 0.012
2022 0.011
2023 0.015
2024 0.007

A source specific assessment for high-rate consumers of locally grown foodstuffs gave an exposure that was less than the ‘total dose’ in 2024 (Table 4.1). As in recent years, the estimated dose was 0.005mSv. The dose to a local fish and shellfish consumer (including external radiation but excluding naturally occurring radionuclides) was 0.007mSv in 2024, and down from 0.015mSv in 2023. The reason for the decrease in dose was the same as for the ‘total dose’.

As in previous years, a source specific assessment was not undertaken to determine the exposure from naturally occurring radionuclides in 2024, as a consequence of reported polonium-210 concentrations in mollusc samples. Prior to 2019, winkle samples collected from South Gare (inside the Tees Estuary entrance) also included some winkles taken from the estuary entrance near Paddy’s Hole. The area near Paddy’s Hole is polluted with oil and other wastes and therefore a potential reason for enhanced naturally occurring radionuclides in molluscs. As in previous years, due to limited availability, a winkle sample was not collected from Paddy’s Hole in 2024. This estimate assumes that the median concentrations for naturally occurring radionuclides at background (Appendix 6, Table A6.2) be subtracted from the total concentrations as measured in 2024.

4.1.4.2. Gaseous discharges and terrestrial monitoring

Gaseous radioactive waste is discharged via stacks to the local environment. Gaseous discharges in 2024 were broadly similar, compared to those in 2023. Analyses of tritium, carbon-14, sulphur-35 and gamma-emitting radionuclides were carried out in milk and crop samples. Samples of freshwater were also taken from boreholes. Data for 2024 are given in Table 4.5(a). As in recent years Carbon-14 concentrations was in food (wheat and potatoes) in 2024. Carbon-14 was also detected in locally produced milk at concentrations slightly above the default value used to represent background. Tritium, and gross beta concentrations in freshwater were below the investigation levels for drinking water in the Water Supply (Water Quality) (Amendment) 2018 Regulations (retained from the European Directive 2013/51).

4.1.4.3. Liquid waste discharges and aquatic monitoring

Permitted discharges of radioactive liquid effluent are made to Tees Bay with non-radioactive trade effluents being discharged directly to the River Tees. Liquid discharges of tritium decreased in 2024 compared to 2023. Tritium discharges are directly related to power output and the reduction in liquid tritium discharges can be attributed to the increased time that the Hartlepool reactors were off-line undergoing maintenance or refuelling during outages.

Results of the aquatic monitoring programme conducted in 2024 are shown in Table 4.5(a) and Table 4.5(b). Unlike in 2023, the carbon-14 concentrations measured in the mollusc samples (winkles) were found to be slightly above the expected background (Table A6.2). Carbon-14 concentrations in fish and crustaceans were generally similar in 2024, compared to those in recent years.

The analysis of technetium-99 in seaweed is used as a specific indication of the far-field effects of disposals to sea from Sellafield. As in previous years, technetium-99 in seaweed was low and much less than the peak concentration observed in 2008 (Environment Agency, Food Standards Agency, Food Standards Scotland, Natural Resources Wales and others 2019). Technetium-99 concentrations in seaweed are less than 1% of the equivalent concentrations near Sellafield.

As in recent years, iodine-131 was positively detected in seaweed samples collected around the mouth of the River Tees Estuary in 2024. The detected values, as in previous years, are believed to originate from the therapeutic use of this radionuclide in local hospitals. Detectable concentrations of caesium-137 were mainly due to disposals from Sellafield and fallout from nuclear weapons testing. However, caesium-137 concentrations in sediment have remained low for several years (Figure 4.8). Overall, gamma dose rates over intertidal sediment in 2024 were similar (where comparisons can be made from similar ground types and locations), to those observed in 2023.

Figure 4.8. Caesium-137 concentration, in Bq kg-1 (dry), in marine sediments near Hartlepool nuclear power station between 2013 and 2024.
Year 137Cs concentration Bq Kg-1 (dry)
2013 2.4
2014 1.8
2015 1.4
2016 1.2
2017 1.3
2018 1.1
2019 1.5
2020 1.0
2021 0.91
2022 0.70
2023 0.76
2024 1.9

In 2024, the reported polonium-210 and lead-210 concentrations in winkles from South Gare are values expected due to naturally occurring sources (given in Appendix 6, Table A6.1). As in recent years, a winkle sample could not be collected from the estuary entrance near Paddy’s Hole in 2024.

4.1.5. Heysham, Lancashire

Heysham Power Station is situated on the Lancashire coast, to the south of Morecambe and near the port of Heysham. This establishment comprises of 2 separate nuclear power stations, Heysham 1 and Heysham 2, each powered by twin AGRs. Heysham 1 commenced operation in 1983 and Heysham 2 began operating in 1988. It is estimated that Heysham 1 and 2 will continue to generate electricity until 2027 and 2030, respectively. Disposals of radioactive waste from both stations are permitted via separate and adjacent outfalls to Morecambe Bay and via stacks. However, in RIFE, both stations are considered together for purposes of environmental monitoring, because the discharges from both sites impact on the same area.

The most recent habits survey was conducted in 2016 (Garrod and others 2017).

4.1.5.1. Doses to the public

The ‘total dose’ from all pathways and sources of radiation was 0.016mSv in 2024 (Table 4.1) or less than 2% of the dose limit for members of the public. This is a small increase from 0.015mSv in 2023. As in recent years, the representative person was an adult spending time over sediments. The small increase in ‘total dose’ in 2024 was mostly due to higher gamma dose rates measured over sand compared to those in 2023.

The trend in ‘total dose’ over the period 2013 to 2024 is given in Figure 4.9. The annual ‘total dose’ ranged between 0.010 and 0.028mSv and were below the dose limit.

Figure 4.9. ‘Total dose’, in mSv y-1, at Heysham nuclear power stations, 2013 to 2024.
Year Dose, mSv y-1
Dose limit 1.0
2013 0.028
2014 0.023
2015 0.023
2016 0.019
2017 0.025
2018 0.010
2019 0.018
2020 0.010
2021 0.015
2022 0.016
2023 0.015
2024 0.016

Source specific assessments for high-rate terrestrial food consumption, and from external exposure for turf cutting over salt marsh, give exposures that were less than the ‘total dose’ in 2024 (Table 4.1). The estimated dose for terrestrial food consumption was less than 0.005mSv in 2024 and slightly down from 0.006mSv in 2023. The small decrease in dose from terrestrial food consumption was mostly attributed to a lower maximum concentration of carbon-14 in milk measured in 2023. The estimated dose to the turf cutters was less than 0.005mSv in 2024 and unchanged from recent years. The dose to a local fisherman, who was considered to consume a large amount of seafood and was exposed to external radiation over intertidal areas, was 0.020mSv in 2024, which was 2% of the dose limit for members of the public of 1mSv and slightly down from 0.021mSv in 2023 (Table 4.1).

4.1.5.2. Gaseous discharges and terrestrial monitoring

Both stations discharge gaseous radioactive waste via stacks to the atmosphere. Gaseous discharges of carbon-14 from Heysham 1 in 2024 were lower than those in 2023. The gaseous discharges of sulphur-35 from Heysham 2 were also down in comparison with those reported in 2023. The monitoring programme for determining the effects of gaseous disposals was similar to that for other power stations. Data for 2024 are given in Table 4.6 (a). As in 2023, sulphur-35 was positively detected in silage in 2024. As in 2023, the carbon-14 concentrations in milk were above the default value used to represent background in 2024 but were lower than those observed in 2023. Tritium, gross alpha and gross beta concentrations in freshwater were below the investigation levels for drinking water in the Water Supply (Water Quality) (Amendment) 2018 Regulations (retained from the European Directive 2013/51).

4.1.5.3. Liquid waste discharges and aquatic monitoring

Permitted discharges of radioactive liquid effluent are made via outfalls into Morecambe Bay. Liquid discharges from Heysham 1 and 2, in 2024 were broadly similar in comparison with recent years.

The monitoring programme for the effects of liquid disposals included sampling of fish, shellfish, sediment, seawater and measurements of gamma dose rates. For completeness, the data considered in this section include all of those for Morecambe Bay. A substantial part of the programme is in place to monitor the effects of Sellafield disposals. The results for 2024 are given in Table 4.6(a) and Table 4.6(b). In general, activity concentrations in 2024 were similar (in comparison to those in recent years) and the effect of liquid disposals from Heysham was difficult to detect above the Sellafield background, based upon the greater historical discharges from Sellafield and monitoring data prior to operation of Heysham 1 and 2. Plutonium radionuclides and americium-241 concentrations in mussels and concentrations of technetium-99 in marine samples originating from Sellafield discharges were similar to those observed in 2023. As in recent years, strontium-90 was detected at low concentrations (reported as just above, or close to, the less than value) in food samples collected in 2024. Gamma dose rates measured over sand were higher in 2024 (in comparison to 2023). Concentrations of caesium-137 in sediment samples near the Heysham nuclear power stations is given in Figure 4.10 over the period 2013 to 2024. There has been variability from year to year, with a large Sellafield influence.

Figure 4.10. Caesium-137 concentration, in Bq kg-1 (dry), in marine sediments near Heysham nuclear power stations between 2013 and 2024.
Year 137Cs concentration Bq Kg-1 (dry)
2013 46
2014 33
2015 16
2016 36
2017 27
2018 24
2019 28
2020 23
2021 48
2022 40
2023 53
2024 25

4.1.6. Hinkley Point, Somerset

The Hinkley Point Power Station sites are situated on the Somerset coast, west of the River Parrett estuary. There are 2 separate stations, A and B, that include 2 Magnox reactors and 2 AGRs, respectively. Hinkley Point A started electricity generation in 1965 and ceased in 1999. This station completed de-fuelling in 2004 and is undergoing decommissioning. Hinkley Point B ended power generation and entered its de-fuelling phase in 2022. A single environmental monitoring programme covers the effects of the 2 power stations, because the discharge effects from both sites impact on the same area. The most recent habits survey was conducted in 2024 (Greenhill, Moore and others 2025).

The construction of the 2 new generation EPRTM reactors continues at Hinkley Point C. Summary details of earlier environmental permits issued (by the Environment Agency), the pre-construction safety case (approved by the ONR), the planning consents granted, and other approvals, are available in earlier RIFE reports (for example (Environment Agency, Food Standards Agency, Food Standards Scotland, Natural Resources Wales and others 2019)) and from Hinkley Point decisions on environmental permit applications for a proposed new nuclear power station. In 2024, the first reactor pressure vessel was installed at Hinkley Point C and operation of the first reactor is expected in 2029. The latest information on the project can be found at: Hinkley Point on Gov.uk.

4.1.6.1. Doses to the public

In 2024, the ‘total dose’ from all pathways and sources of radiation was 0.014mSv (Table 4.1), or approximately 1% of the dose limit to members of the public. This is a decrease from 0.032mSv in 2023. The representative person was an adult spending time over sediments (unchanged from 2023). The decrease in ‘total dose’ was mostly due to the revision of habits information.

The trend in ‘total dose’ over the period 2013 to 2024 is given in Figure 4.11. The annual ‘total dose’ ranged between 0.013 and 0.041mSv and were below the dose limit.

Figure 4.11. ‘Total dose’, in mSv y-1, at Hinkley Point nuclear power stations, 2013 to 2024.
Year Dose, mSv y-1
Dose limit 1.0
2013 0.022
2014 0.022
2015 0.016
2016 0.013
2017 0.032
2018 0.041
2019 0.021
2020 0.023
2021 0.030
2022 0.015
2023 0.032
2024 0.014

A source specific assessment for a high-rate consumer of locally grown food gave an exposure that was less than the ‘total dose’ in 2024 (Table 4.1). The dose to this consumer of locally grown food was less than 0.005mSv in 2024. A source specific assessment for local people who consume high rates of seafood and are exposed to external radiation over intertidal area gave an exposure of 0.014mSv, down from 0.020mSv in 2023. The main reason for the decrease in dose was the same as that contributing to the maximum ‘total dose’. This dose estimate also includes the effects of (historical) discharges of tritium from the Maynard Centre, the former GE Healthcare Limited plant at Cardiff[footnote 9] and uses an increased dose coefficient (see Appendix 5). The estimated dose for a houseboat occupant was not estimated as no houseboat occupant was identified and reported during the habits survey conducted in 2024.

4.1.6.2. Gaseous discharges and terrestrial monitoring

Gaseous radioactive waste is discharged via separate stacks to the local environment. Gaseous discharges in 2024 were similar in comparison with 2023. Analyses of milk, fruit, honey and crops were undertaken to measure activity concentrations of tritium, carbon-14, sulphur-35 and gamma-emitting radionuclides. Local reservoir water samples were also analysed. Data for 2024 are given in Table 4.7(a). Activity concentrations of tritium and gamma-emitting radionuclides (cobalt-60 and caesium-137) in all terrestrial materials were reported as less than values. As in 2023, sulphur-35 was positively detected in food samples (barley) in 2024. The carbon-14 concentrations in locally produced milk were lower than values observed in 2023. Carbon-14 was also detected in blackberries (as in previous years) above the expected background value in 2024. Tritium, gross alpha and gross beta concentrations in reservoir water were below the investigation levels for drinking water in the Water Supply (Water Quality) (Amendment) 2018 Regulations (retained from the European Directive 2013/51).

4.1.6.3 Liquid waste discharges and aquatic monitoring

Permitted discharges of radioactive liquid effluent from both power stations are made via separate outfalls into the Bristol Channel. Discharges of tritium from Hinkley Point A and B decreased in 2024 compared to 2023. Discharges of caesium-137 from Hinkley A also decreased in 2024 compared to 2023. Analyses of seafood and marine indicator materials and measurements of external radiation were conducted over intertidal areas. The environmental results for 2024 are given in Table 4.7(a) and Table 4.7(b). Overall, activity concentrations observed in seafood collected from the Bristol Channel were generally similar to those in previous years. As in recent years, tritium was positively detected in seafood (shrimps and grey mullet) in 2024. Concentrations of other radionuclides in the aquatic environment represent the combined effect of releases from these stations, plus other establishments that discharge into the Bristol Channel. Other contributors to the aquatic environment are Sellafield, and fallout from Chernobyl and nuclear weapons testing. The concentrations of transuranic nuclides in seafoods were of negligible radiological significance. Trends of caesium-137 concentrations in sediment are shown in Figure 4.12.

In early 2024, elevated concentrations of strontium-90 and caesium-137 were observed in sediment samples throughout the Hinkley Point aquatic area, however, these concentrations returned to normal levels in samples taken in the second half of the year (see Table 4.7(a) for the individual results). There was no corresponding elevation in americium-241 concentrations which remained similar to those reported in recent years, gamma dose rates over intertidal substrates in 2024 were generally lower (where comparisons can be made for similar ground types and locations), in comparison to those observed in 2023.

The Environment Agency and its analytical laboratory investigated the elevated strontium-90 and caesium-137 results, including recounting samples, analysis of archive samples, laboratory audits and swab testing which demonstrated that no cross-contamination or other events occurred that would explain the increase. Also, there was not a corresponding increase in discharges to explain the increases, nor does an environmental mechanism for the increase across a wide geographic area and short time span appear likely either. For example, the activity concentrations of older sediments were not high enough to explain the increase even if storms, etc had resulted in their being redistributed.

To investigate the impact of the elevated quarter 1 results, the external dose was calculated using simple mathematical models (Hunt 1984) with the sediment concentrations for the pipeline location (most impacted) and the high-rate intertidal occupancy value (actually found at Stolford) as the inputs. The external dose was calculated to be 0.014mSv. For comparison, the external dose calculated at the pipeline in 2023, again using the same high-rate occupancy value to ensure a like for like comparison was 0.0002mSv.

In addition, the total dose has been calculated using the sediment concentrations, which is different to the usual way of using the gamma dose rates. In 2024, the ‘total dose’ using sediment concentrations is 0.014mSv, compared to 0.006mSv in 2023. Although this value has increased between 2023 and 2024 it is still well below the dose limit of 1mSv y-1 and approximately 1% of the dose limit.

Figure 4.12. Caesium-137 concentration, in Bq kg-1 (dry), in marine sediments near Hinkley Point nuclear power stations between 2013 and 2024.
Year 137Cs concentration Bq Kg-1 (dry)
2013 18
2014 15
2015 11
2016 10
2017 13
2018 12
2019 12
2020 20
2021 9.2
2022 7.6
2023 6.9
2024 79

4.1.7. Sizewell, Suffolk

The 2 Sizewell Power Stations are located on the Suffolk coast, near Leiston. Sizewell A has 2 Magnox reactors that ceased electricity generation in 2006. De-fuelling commenced in 2007 and was completed in 2014. Sizewell B, powered by one reactor, is the only commercial PWR power station in the UK. The Sizewell B power station began operation in 1995 and whilst the end of power generation is currently scheduled for 2035, a proposal has been initiated by EDF to extend operations by 20 years. The most recent habits survey was conducted in 2015 (Garrod, Clyne & Papworth 2016).

In 2020, Sizewell C Limited (previously NNB GenCo (SZC) Limited) applied to the ONR for a nuclear site license, the Environment Agency for a radioactive substances activities permit and the Planning Inspectorate for a Development Consent Order (DCO). Sizewell C Limited intends to construct 2 EPRTM reactors at a site north of the existing Sizewell B site. In 2022, the Secretary of State for the Department of Business, Energy and Industrial Strategy announced that the Sizewell C project had been granted its DCO. In 2023, the Environment Agency granted the permit for discharging and disposing of radioactive waste in the environment. In May 2024, ONR granted its nuclear site license. Further information can be found at: Sizewell nuclear regulation on gov.uk.

Gaseous and liquid discharges of radioactivity from Sizewell C are not expected to begin until active commissioning of the station in the mid-2030s.

4.1.7.1. Doses to the public

The ‘total dose’ from all pathways and sources of radiation was 0.014mSv in 2024 (Table 4.1) or approximately 1% of the dose limit to members of the public. This is an increase from 0.010mSv in 2023. The representative person in 2024 was an adult living close to the site, unchanged from 2023. The increase in ‘total dose’ was mostly attributed to a higher estimate of direct radiation in 2024 (due to changes in the estimated background dose rate). The trend in ‘total dose’ over the period 2013 to 2024 is given in Figure 4.13. Any variation in ‘total dose’ from year to year was largely due to a change in the contribution from direct radiation from the site, which has been low in recent years. The ‘total dose’ has declined (reduced by a factor of 5 or 6), following the closure of the Magnox reactors at Sizewell A in 2006 (Environment Agency, Food Standards Agency, Food Standards Scotland, Natural Resources Wales and others 2018).

Figure 4.13. ‘Total dose’, in mSv y-1, at Sizewell nuclear power stations, 2013 to 2024.
Year Dose, mSv y-1
Dose limit 1.0
2013 0.021
2014 0.020
2015 0.021
2016 0.021
2017 0.021
2018 0.026
2019 0.010
2020 0.017
2021 0.016
2022 0.011
2023 0.010
2024 0.014

As in recent years, source specific assessments for both a high-rate consumer of locally grown foodstuffs, and of fish and shellfish, and of external exposure for houseboat occupancy, gave exposures that were also less than 0.005mSv in 2024 (Table 4.1).

4.1.7.2. Gaseous discharges and terrestrial monitoring

Discharges of carbon-14 increased from Sizewell B in 2024, compared to in 2023. This reflects the typical cyclical nature of the operation of a PWR following the fuel cycle and reactor outages. Gaseous discharges tend to increase towards the end of the fuel cycle, and the reactor ran from April 2023 to October 2024 when it was taken offline for Reactor Outage 19.

The results of the terrestrial monitoring in 2024 are shown in Table 4.8(a). As in recent years, gamma-ray spectrometry and radiochemical analysis of tritium and sulphur-35 in milk and crops generally showed very low concentrations of artificial radionuclides near the power stations in 2024. In 2024, carbon-14 concentrations in produced milk were just above the estimated background level. As in 2023, sulphur-35 and caesium-137 were positively detected at a very low concentration in a grass sample collected in 2024. As in recent years, tritium concentrations in local freshwater were reported as less than values in 2024. Tritium, gross alpha and gross beta concentrations in surface water were below the investigation levels for drinking water in the Water Supply (Water Quality) (Amendment) 2018 Regulations (retained from the European Directive 2013/51).

4.1.7.3. Liquid waste discharges and aquatic monitoring

Permitted discharges of radioactive liquid effluent are made via outfalls to the North Sea. Liquid discharges of tritium from Sizewell B increased in 2024, in comparison with those in 2023, which reflect the typical cyclical nature of the operation of a PWR. Aqueous tritium discharges tend to increase towards the end of the fuel cycle; the reactor ran from April 2023 to October 2024 when it was taken offline for Reactor Outage 19. The project to drain the fuel storage pond at Sizewell A was completed in 2019. This has resulted in a significant reduction in liquid effluent generation at Sizewell A. As part of the aquatic programme, analysis of seafood, seaweed, sediment, and seawater, and measurements of gamma dose rates were conducted in intertidal areas. Data for 2024 are given in Table 4.8(a) and Table 4.8(b). Concentrations of artificial radionuclides from other sources (such as historic Sellafield discharges, fallout from Chernobyl, and nuclear weapons testing) were low, as demonstrated in Figure 8.9(b). Unlike in 2023, tritium was not positively detected in seafood. As in recent years, concentrations of strontium-90 observed in sediment samples were all reported as less than values and concentrations of caesium-137 were very low. Caesium-137 concentrations in sediment have remained low over the last decade and are generally decreasing over time (Figure 4.14). Overall, gamma radiation dose rates over intertidal areas were difficult to distinguish from the natural background and were similar to those reported in recent years.

Figure 4.14. Caesium-137 concentration, in Bq kg-1 (dry), in marine sediments near Sizewell nuclear power stations between 2013 and 2024.
Year 137Cs concentration Bq Kg-1 (dry)
2013 7.0
2014 5.7
2015 6.7
2016 5.8
2017 5.8
2018 5.5
2019 4.6
2020 4.8
2021 4.3
2022 4.1
2023 4.4
2024 4.1

4.2. Scotland

4.2.1. Chapelcross, Dumfries and Galloway

Chapelcross was Scotland’s first commercial nuclear power station. It has 4 Magnox reactors and is located near the town of Annan in Dumfries and Galloway. After 45 years of continuous operation, electricity generation ceased in 2004, and the station has since been undergoing decommissioning. De-fuelling of the reactors began in 2008 and was completed during 2013. The major hazards remaining on the site are being addressed during the decommissioning phase.

Habits surveys have been undertaken to investigate aquatic and terrestrial exposure pathways. The most recent habits survey for Chapelcross was conducted in 2022. In 2024, a separate habits survey was also conducted to determine the consumption and occupancy rates by members of the public on the Dumfries and Galloway coast. Copies of the most recent habits surveys are available from SEPA by emailing RSEnquiries@sepa.org.uk. The results of this survey are used to determine the potential exposure pathways relating to permitted liquid discharges from the Sellafield nuclear site in Cumbria (see Section 3.3.1).

In 2023, the site applied for a variation to their EASR18 permit. The application was for increasing the gaseous discharge limits for all radionuclides apart from tritium, to support ongoing decommissioning activities.

4.2.1.1. Doses to the public

The ‘total dose’ from all pathways and sources of radiation was 0.007mSv in 2024 (Table 4.1), or less than 1% of the dose limit to members of the public. This is a decrease from 0.010mSv in 2023. As in recent years, the representative person was an infant consuming locally produced milk at high rates. The decrease in dose was mainly due to the exclusion of the concentrations of carbon-14 in milk samples from the calculation of the ‘total dose’. The trend in ‘total dose’ over the period 2013 to 2024 is given in Figure 4.15, doses are generally low, with small peaks observed in 2013 and 2017 (still less than 5% of the dose limit to members of the public).

Figure 4.15. ‘Total dose’, in mSv y-1, at Chapelcross nuclear power station, 2013 to 2024.
Year Dose, mSv y-1
Dose limit 1.0
2013 0.024
2014 0.014
2015 0.022
2016 0.026
2017 0.035
2018 0.019
2019 0.007
2020 0.018
2021 0.018
2022 0.009
2023 0.010
2024 0.007

As in 2023, source specific assessments for a high-rate consumer of locally grown food, and for a seafood (salmon) and wildfowl consumer, gave exposures that were less than the ‘total dose’ in 2024 (Table 4.1). The dose for the terrestrial food consumer was estimated to be 0.006mSv in 2024, down from 0.009mSv in 2023. The decrease in dose was mostly due to the same reason as for the ‘total dose’. The dose for the seafood and wildfowl consumer was less than 0.005mSv in 2024 and unchanged from 2023. Crustacean consumption was not identified in the recent habits survey.

Doses from the presence of artificial radionuclides in marine materials in the Chapelcross vicinity are mostly due to the effects of Sellafield discharges and are consistent with values expected at this distance from Sellafield.

4.2.1.2. Gaseous discharges and terrestrial monitoring

Gaseous radioactive waste is discharged via stacks to the local environment.

Terrestrial monitoring consisted of the analysis of a variety of foods, including milk, fruit, crops as well as grass, soil and freshwater samples, for a range of radionuclides. Air samples at 3 locations were also monitored to investigate the inhalation pathway. The results of terrestrial food and air monitoring in 2024 are given in Table 4.9(a) and Table 4.9(c). Carbon-14 concentrations in milk were lower than those observed in 2023. As in recent years, americium-241 concentrations in all terrestrial food, and grass samples were all reported as less than values.

As in 2023, tritium was positively detected in the freshwater sample collected at Gullielands Burn. However, tritium, gross alpha and gross beta concentrations in all freshwater samples were well below the investigation levels for drinking water in the Water Supply (Water Quality) (Amendment) 2018 Regulations (retained from the European Directive 2013/51). Activity concentrations in air samples at locations near to the site (Table 4.9(c)) were reported as less than values (or close to the less than value). Solid waste transfers in 2024 are also given in Appendix 1 (Table A1.4).

4.2.1.3. Liquid waste discharges and aquatic monitoring

Radioactive liquid effluents are discharged to the Solway Firth. Unlike in 2023, radioactive effluent was discharged from the site on a number of occasions in support of ongoing decommissioning activities. Samples of seawater and seaweed (‘Fucus vesiculosus’), used as environmental indicators, were collected in addition to shrimps, mussels, fish (salmon), sediments and measurements of gamma dose rates. Data for 2024 are given in Table 4.9(a) and Table 4.9(b). Concentrations of artificial radionuclides in marine materials in the Chapelcross vicinity are mostly due to the effects of Sellafield discharges and are consistent with values expected at this distance from Sellafield. Concentrations of most radionuclides remained similar to those detected in recent years. As in previous years, low concentrations of europium-155 were positively detected (reported as just above the less than value) in sediment samples.

As in previous years, concentrations of caesium-137, plutonium radionuclides and americium-241 were enhanced in sediment samples taken close to the pipeline in 2024. The average concentration of caesium-137 in sediments analysed in 2024 was slightly lower than in 2023 and is known to be largely due to Sellafield discharges (Figure 4.16). In 2024, gamma dose rates over intertidal sediment were similar to those in 2023 (where comparisons can be made). As in previous years, measurements of the contact beta dose rate on sediments were reported as less than values in 2024.

Figure 4.16. Caesium-137 concentration, in Bq kg-1 (dry), in marine sediments near Chapelcross nuclear power station between 2013 and 2024.
Year 137Cs concentration Bq Kg-1 (dry)
2013 59
2014 72
2015 72
2016 59
2017 55
2018 56
2019 58
2020 97
2021 70
2022 39
2023 61
2024 47

Between 1992 and 2009, several particles were found at the end of the discharge outfall consisting of limescale originating from deposits within the pipeline. The site operator continues to monitor this area frequently and no particles were found during 2024 (as for the previous years). The relining of the pipeline and grouting at strategic points, which was undertaken between 2009 and 2010, has reduced the potential for particles to be released.

4.2.2. Hunterston, North Ayrshire

Hunterston Power Station is located on the Ayrshire coast near West Kilbride and consists of 2 separate nuclear power stations - Hunterston A and Hunterston B.

Hunterston A was powered by 2 Magnox reactors until it ceased electricity production in 1990 and is now being decommissioned by Nuclear Restoration Services (NRS). De-fuelling was completed in 1995. Decommissioning activities continue to focus on 2 major areas: the ongoing decommissioning of the cartridge (nuclear fuel) cooling pond; and making progress towards ensuring that all higher activity waste is stored in a passively safe manner.

Most of the radioactivity in liquid effluent discharged from the Hunterston A site over the last few years has arisen from the cartridge cooling pond. The draining of the cartridge cooling pond is now largely complete. However, there is still a need to manage the remaining radioactive sludges from several areas associated with the pond.

In October 2023, SEPA received an application from NRS to vary the permit, made under the Environmental Authorisations (Scotland) Regulations 2018 (EASR18), for the Hunterston A site. The variation application includes the addition of the Solid Intermediate Level Waste Encapsulation plant (SILWE) facility discharge stack to the site permit, and an increase to the site gaseous discharge limits. The permit variation application went to public consultation in late October 2024.

In March 2024, SEPA received another application from NRS to amend its EASR18 permit. The requested changes include removing the minimum flow requirement during aqueous discharges (7 m3 s-1) and eliminating the tidal window restriction (one hour after high tide to one hour before low tide). The discharge point will remain unchanged, and no other limits will be altered.

In terms of safe management of legacy higher activity waste at Hunterston A, NRS are in the process of commissioning the SILWE. The Wet Intermediate Level Waste Retrieval and Encapsulation Plant (WILWREP) has finalised modifications for processing radioactively contaminated acid wastes and is currently going through active commissioning. Processing of the legacy higher activity waste, present at the Hunterston A site will be processed through either SILWE or WILWREP, with the current plans being to make safe by encapsulating it in a grout mixture. The encapsulated waste will then be transferred to the Intermediate Level Waste Store (ILWS) for storage.

Hunterston B was powered by a pair of AGRs, referenced as Reactors 3 and 4. Electricity production was ceased in 2022, and defueling operations were undertaken by EDF Energy Nuclear Generation Limited. Both reactors are now defueled. Once it has achieved Fuel Free Verification (see Appendix 2 for definition), it will be transferred to the NDA Estate to be decommissioned by NRS. Both gaseous and liquid discharges are much lower during defueling than during the operational phase.

Hunterston B has also applied to vary its permit for radioactive substances activities to remove the minimum flow during aqueous discharges (7m3 s-1) as well as the tidal window (one hour after high tide to one hour before low tide). The discharge point will remain unchanged, and no other limits will be altered.

In terms of safe management of legacy higher activity waste at Hunterston B, the preferred option is to use the ILWS on Hunterston A. Optioneering exercises are being carried out on the optimal solution for the Operational Waste Processing Facility (OWPF), which will manage the higher activity wastes arising from the station’s operational life. The Decommissioning Waste Processing Facility (DWPF) will be refurbished and used to manage the lower activity waste arising from the decommissioning phase.

Environmental monitoring in the area considers the effects of both Hunterston A and Hunterston B sites together. The most recent habits survey was conducted in 2024 and available from SEPA by emailing RSEnquiries@sepa.org.uk.

4.2.2.1 Doses to the public

The ‘total dose’ from all pathways and sources of radiation was 0.006mSv in 2024 or less than 1% of the dose limit (Table 4.1) to members of the public. This is a decrease from 0.013mSv in 2023. The representative person was prenatal children of an adult living near the site, a change from that in 2023 (adults consuming game meat). The decrease in dose was mostly due to a revised habits data excluding game meat. The trend in ‘total dose’ over the period 2013 to 2024 is given in Figure 4.17, doses have generally decreased since 2018, with some variability observed over this period.

Figure 4.17. ‘Total dose’, in mSv y-1, at Hunterston nuclear power stations, 2013 to 2024. (Small doses less than or equal to 0.005mSv are recorded as being 0.005mSv).
Year Dose, mSv y-1
Dose limit 1.0
2013 0.021
2014 0.021
2015 0.025
2016 0.021
2017 0.023
2018 0.005
2019 0.005
2020 0.005
2021 0.006
2022 0.005
2023 0.013
2024 0.006

The estimated dose for seafood consumption was 0.008mSv in 2024 which was less than 1% of the dose limit for members of the public of 1mSv and up from 2023 (less than 0.005mSv). The reason for the increase in dose was mainly due to the revision of habits data presenting higher fish consumption rates.

The estimated dose for a terrestrial food consumer was 0.009mSv in 2024, which was less than 1% of the dose limit for members of the public of 1mSv and up compared to that in 2023 (0.006mSv). The reason for the increase in dose was mainly due to a higher caesium-137 concentration in the game sample selected in 2024 (venison).

4.2.2.2. Gaseous discharges and terrestrial monitoring

Gaseous discharges are made via separate discharge points from the Hunterston A and Hunterston B stations. Discharges of all other radionuclides (excluding tritium and carbon-14) from Hunterston A increased in 2024 in comparison with 2023. The increase observed in 2024 was due to an encapsulation facility on site entering active commissioning. This facility is used to encapsulate radioactive acid which is classified as intermediate level waste. Gaseous radioactive waste discharges from the site remain low in comparison to current site limits which are recognised as being low in comparison to other NRS sites. Hunterston B defueled Reactor 3 in September 2023 and was defueling Reactor 4 in 2024. As a consequence of being shut down, gaseous discharges remained low in 2024.

There is a substantial terrestrial monitoring programme which includes the analyses of a comprehensive range of wild and locally produced foods. In addition, air, freshwater, grass and soil are sampled to provide background information. The results of terrestrial food and air monitoring in 2024 are given in Table 4.10(a) and Table 4.10(c). The concentrations of radionuclides in air, milk, crops and fruit were generally low and similar to those in previous years (where comparisons can be made). The concentration of ceasium-137 in venison was higher in 2024 in comparison to those observed in 2023. As in 2023, sulphur-35 was positively detected in grass in 2024. Tritium, gross alpha and gross beta concentrations in freshwater were below the investigation levels for drinking water in the Water Supply (Water Quality) (Amendment) 2018 Regulations (retained from the European Directive 2013/51).

All activity concentrations in air at locations near to the site (Table 4.10(c)) were reported as less than values. Solid waste transfers in 2024 are also given in Appendix 1 (Table A1.4).

4.2.2.3. Liquid waste discharges and aquatic monitoring

Authorised liquid discharges from both Hunterston stations are made to the Firth of Clyde via the Hunterston B station’s cooling water outfall. The primary source of liquid discharges from Hunterston A, is the cartridge cooling pond, draining of which is nearly complete (reducing the radiological hazards on site), which is supported by nil discharges of plutonium-241.

The main part of the aquatic monitoring programme consists of sampling of fish and shellfish and the measurement of gamma and beta dose rates on the foreshore. Samples of sediment, seawater and seaweed are analysed as environmental indicator materials.

The results of aquatic monitoring in 2024 are shown in Table 4.10(a) and Table 4.10(b). The concentrations of artificial radionuclides in the marine environment are predominantly due to Sellafield discharges, the general values being consistent with those to be expected at this distance from Sellafield. As in recent years, the concentrations of Sellafield derived technetium-99 in crabs and lobsters around Hunterston were low. All cobalt-60 concentrations in sediments were reported as less or close to the less than value in 2024. In 2024, plutonium and americium-241 concentrations in seafood were generally similar to those observed in recent years. Gamma dose rates were generally similar in 2024, in comparison to those observed in recent years. Measurements of the beta dose rates over sand are reported as less than values in 2024. Caesium-137 concentrations in sediment have remained low over the last decade (Figure 4.18).

Figure 4.18. Caesium-137 concentration, in Bq kg-1 (dry), in marine sediments near Hunterston nuclear power stations between 2013 and 2024.
Year 137Cs concentration Bq Kg-1 (dry)
2013 3.2
2014 4.7
2015 3.6
2016 5.6
2017 3.9
2018 3.9
2019 4.3
2020 3.8
2021 5.3
2022 4.1
2023 3.4
2024 4.3

4.2.3. Torness, East Lothian

Torness Power Station is located near Dunbar on the east coast of Scotland. The station is powered by twin AGRs and began operation at the end of 1987. In December 2024, EDF Energy Nuclear Generation Limited confirmed a 2-year extension of power generation at Torness, extending its operational life until 2030. EDF keeps operational dates under constant review which has allowed them to provide the additional clarity on lifetime expectations.

Since 2022, reactors are only refuelled when they are offloaded and depressurised. This has had an impact on the profile of discharges notably carbon-14, sulphur-35 and tritium. However, there has been no significant impact to the magnitude of the annual discharges.

The gaseous and liquid discharges from the site are given in Appendix 1.

The most recent habits survey, to determine the consumption and occupancy rates by members of the public was published in 2025 and copies can be requested from SEPA by emailing RSEnquiries@sepa.org.uk.

4.2.3.1. Doses to the public

In 2024, the ‘total dose’ from all pathways and sources of radiation was 0.011mSv (Table 4.1), or approximately 1% of the dose limit to members of the public. This is a slight increase from 0.007mSv in 2023. The main reason for the increase in dose is a higher estimate of direct radiation from the site. In 2024, the representative person was a prenatal child of a local inhabitant consuming domestic fruits and unchanged from 2023. The trend in ‘total dose’ over the period 2013 to 2024 is given in Figure 4.19. The decrease in ‘total dose’ in the earlier years reflected a downward trend in the reported direct radiation, thereafter ‘total dose’ has remained broadly similar, from year to year, and were low.

Figure 4.19. ‘Total dose’, in mSv y-1, at Torness nuclear power station, 2013 to 2024. (Small doses less than or equal to 0.005mSv are recorded as being 0.005mSv).
Year Dose, mSv y-1
Dose limit 1.0
2013 0.020
2014 0.020
2015 0.020
2016 0.021
2017 0.021
2018 0.005
2019 0.005
2020 0.006
2021 0.005
2022 0.006
2023 0.007
2024 0.011

The source specific assessment for a high-rate consumer (infant) of terrestrial food gave an exposure that was 0.007mSv in 2024 (Table 4.1) and a small increase from 2023 (0.006mSv). The estimated dose to a high consumer of local fish and shellfish was less than 0.005mSv in 2024, or less than 0.5% of the dose limit for members of the public of 1mSv, and unchanged from that in recent years.

4.2.3.2. Gaseous discharges and terrestrial monitoring

A variety of foods, including milk, crops, fruit, and game as well as grass, soil and freshwater samples, were measured for a range of radionuclides. Air sampling at 3 locations was undertaken to investigate the inhalation pathway. The results of terrestrial food and air monitoring in 2024 are given in Table 4.11(a) and Table 4.11(c). Activity concentrations in many terrestrial foods are reported as less than values (or close to the less than value). The carbon‑14 concentrations in locally produced milk were close to the default value used to represent background. Caesium-137 was positively detected in soil, but at low concentrations. As in recent years, americium-241 concentrations in all terrestrial food and soil samples (measured by gamma–ray spectrometry) were reported as less than values in 2024. The tritium, gross alpha and gross beta concentrations in freshwater were well below the investigation levels for drinking water in the Water Supply (Water Quality) (Amendment) 2018 Regulations (retained from the European Directive 2013/51). Measured concentrations of radioactivity in air, at locations near to the site, were all reported as less than values or close to the less than values in 2024 (Table 4.11(c)). Solid waste transfers in 2024 are also given in Appendix 1 (Table A1.4).

4.2.3.3. Liquid waste discharges and aquatic monitoring

Discharges of authorised liquid radioactive wastes are made to the Firth of Forth. Seafood, seaweed, sediment, and seawater samples were collected in 2024. Measurements were also made of gamma dose rates over intertidal areas, supported by analyses of sediment, and beta dose rate measurements on fishing gear. The results of the aquatic monitoring in 2024 are shown in Table 4.11(a) and Table 4.11(b). Concentrations of artificial radionuclides were mainly due to the distant effects of Sellafield discharges, and fallout from Chernobyl and nuclear weapons testing. Cobalt-60 was only detected positively in winkles and seaweeds collected near the main discharge pipeline in 2024. This activation product was likely to have originated from the station. Technetium-99 concentrations in marine samples were similar to those in recent years. Overall, caesium-137 concentrations in sediments have remained low over the last decade (Figure 4.20). Gamma dose rates over intertidal areas were generally indistinguishable from natural background and were similar to those measured in recent years. Measurements of the contact beta dose rate on fisher’s pots were reported as less than values in 2024.

Figure 4.20. Caesium-137 concentration, in Bq kg-1 (dry), in marine sediments near Torness nuclear power station between 2013 to 2024.
Year 137Cs concentration Bq Kg-1 (dry)
2013 1.4
2014 1.2
2015 3.6
2016 0.87
2017 3.0
2018 1.0
2019 0.96
2020 0.93
2021 0.82
2022 0.80
2023 0.59
2024 0.80

4.3. Wales

4.3.1. Trawsfynydd, Gwynedd

Trawsfynydd Power Station is located inland on the northern bank of Llyn Trawsfynydd in Eryri (Snowdonia) National Park, North Wales and was powered by 2 Magnox reactors. Trawsfynydd stopped generating electricity in 1991. De-fuelling of the reactors was completed in 1995, and the station is being decommissioned. As part of NDA’s site-specific approach to decommissioning, Trawsfynydd was selected as the lead location, where the reactors will be dismantled without a long period of care and maintenance (Nuclear Decommissioning Authority 2021). The most recent habits survey was undertaken in 2018 (Greenhill, Clyne & Moore 2019).

4.3.1.1. Doses to the public

The ‘total dose’ from all pathways and sources of radiation was 0.010mSv in 2024 (Table 4.1), which was 1% of the dose limit to members of the public. This is an increase from 0.007mSv in 2023. The representative person in 2023 was an adult exposed to external radiation over lake sediments and was unchanged from 2023. The increase in ‘total dose’ was mostly attributed to higher caesium-137 concentrations in sediment (and hence calculated gamma dose rate over lake sediments ) in 2024. The trend in ‘total dose’ over the period 2013 to 2024 is given in Figure 4.21, with variations in recent years due to estimates of direct radiation.

Figure 4.21. ‘Total dose’, in mSv y-1, at Trawsfynydd nuclear power station, 2013 to 2024. (Small doses less than or equal to 0.005mSv are recorded as being 0.005mSv).
Year Dose, mSv y-1
Dose limit 1.0
2013 0.017
2014 0.013
2015 0.014
2016 0.019
2017 0.024
2018 0.017
2019 0.005
2020 0.012
2021 0.010
2022 0.009
2023 0.007
2024 0.010

The dose to an angler (who consumes large quantities of fish and spends long periods of time in the location being assessed) was 0.007mSv in 2024 (Table 4.1), which was less than 1% of the dose limit for members of the public of 1mSv and a small increase from 2023 (0.006mSv). The main reason for the small increase in dose was the same as for the ‘total dose’. The activity concentrations observed in lake sediments are used to calculate an external dose rate due to the difficulty in establishing the increase in measured dose rates above natural background rates. The dose to infants (1-year-old) consuming terrestrial food was 0.037mSv, or less than 4% of the dose limit. This was higher than in 2023 (0.034mSv) because of a higher maximum concentration of americium-241 in milk samples collected in 2024.

4.3.1.2. Gaseous discharges and terrestrial monitoring

The results of the terrestrial programme, for local food (including milk) and grass samples in 2024, are shown in Table 4.12(a). Concentrations of activity in all terrestrial samples were low. Tritium concentrations in all milk samples were reported as less than values. Like in 2023, carbon-14 concentrations in milk were reported just above the background concentration. Measured activities for caesium-137 in all terrestrial samples were reported as less than values (or close to the less than value) in 2024. The most likely source of small amounts of caesium-137 is fallout from Chernobyl and nuclear weapons testing, though it is conceivable that a small contribution may be made by re-suspension of lake activity. In recognition of this potential mechanism, monitoring of transuranic radionuclides, which are also associated with liquid discharges from the site (Ministry of Agriculture Fisheries and Food 1993), was also conducted on an apple sample. In 2024, detected activities of transuranic radionuclides in apples were low and generally similar to observations in other areas of England and Wales, where activity was attributable to fallout from nuclear weapons testing. Therefore, there was no direct evidence of re-suspension of activity in sediment from the lake shore contributing to increased exposure from transuranic radionuclides in 2024.

4.3.1.3. Liquid waste discharges and aquatic monitoring

Discharges of liquid radioactive waste are made to a freshwater lake, making the power station unique in UK terms. The aquatic monitoring programme was directed at consumers of freshwater fish caught in the lake and external exposure over the lake shoreline; the important radionuclides are caesium-137 and, to a lesser extent, strontium-90. Freshwater and sediment samples were also analysed in 2024. Brown and rainbow trout were found to be the species regularly consumed in past habits surveys. Most brown trout are indigenous to the lake, but rainbow trout are introduced from a hatchery. Due to the limited period that they spend in the lake, introduced fish generally exhibit lower caesium-137 concentrations than indigenous fish.

Data for 2024 are given in Table 4.12(a) and Table 4.12(b). Most activity concentrations in fish and sediments result from historical discharges, due to inefficient dispersion and binding to sediments (Ministry of Agriculture Fisheries and Food 1993). As in recent years, due to sample availability, only rainbow trout samples were collected in 2024. The most recent brown trout sample to be collected was in 2015 and the concentration of caesium-137 was the lowest reported value for fish indigenous to the lake (Environment Agency, Food Standards Agency, Scotland and others 2016). As in previous years, caesium-137 concentrations in water samples are reported as less than values in 2024. Concentrations in the water column are predominantly maintained by processes that release activity (such as remobilisation) from near surface sediments. Caesium-137 concentrations in lake sediments were higher than those observed in 2023 at all sampling locations apart from the sediment collected near the main discharge pipeline. In 2024, the highest caesium-137 concentration was in a sediment sample collected on the lake shore near a café (320Bq kg-1) and was higher than in 2023 (130Bq kg-1 collected near the main pipeline). Americium-241 was also positively detected in 3 sediment samples (1.7, 0.69 and 1.4Bq kg-1 in the sediment samples collected on the lake shore near a café, 1.5km southeast of the power station and southeast of a footbridge, respectively). In previous years’ monitoring programmes, it has been demonstrated that these concentrations increase with depth beneath the sediment surface. The concentrations of strontium-90 and plutonium-238 in all sediment samples collected in 2024 were reported as less than values and were similar to those observed in recent years. As in 2023, plutonium-239+240 was also positively detected in sediment samples (collected on the lake shore near a café and 1.5km southeast of the power station). Strontium-90 and transuranic concentrations in fish continued to be very low in 2024 and it is the effects of caesium-137 that dominate the external radiation pathways.

In the lake itself, there remains clear evidence for the effects of liquid discharges from the power station (activity concentrations of caesium-137, and other radionuclides, in sediments). However, gamma dose rates measured on the shoreline (where anglers fish) were difficult to distinguish from background dose rates in 2024 and were generally higher (where comparison could be made) to those in 2023. The predominant radionuclide in the dose assessment was caesium-137. The time trends of concentrations of caesium-137 in sediments and discharges are shown in Figure 4.22. A substantial decline in concentrations was observed in the mid to late 1990s in line with reducing discharges. Since 2000, the discharges of caesium-137 have generally decreased, but with some variability. Concentrations have generally decreased over the period 2000 to 2024, with fluctuations due to environmental variability and short periods of increased discharges, particularly in 2012 and 2013.

Figure 4.22. Caesium-137 concentration in sediment, in Bq kg-1 (dry) in Trawsfynydd Lake and liquid discharge, in GBq y-1, from Trawsfynydd 1995 to 2024.

4.3.2. Wylfa, Isle of Anglesey

Wylfa Power Station is located on the north coast of Anglesey and has 2 Magnox reactors. It was the last and largest power station of its type to be built in the UK and commenced electricity generation in 1971 and ceased in 2015. De-fueling operations were completed in 2019 (Nuclear Decommissioning Authority 2020). This milestone marked the end of de-fueling operations at all the UK’s first-generation nuclear reactors.

The most recent habits survey was undertaken in 2023 (Greenhill, Clyne and others 2025).

4.3.2.1. Doses to the public

The ‘total dose’ from all pathways and sources of radiation was 0.008mSv in 2024 (Table 4.1), which was less than 1% of the dose limit to members of the public. This is an increase from less than 0.005mSv in 2023 because of a higher estimate of direct radiation compared to 2023. The representative person was an adult eating marine plants and algae and a change from 2023 (adults spending extensive time over sediments). The trend in ‘total dose’ over the period 2013 to 2024 is given in Figure 4.23. The annual ‘total dose’ have remained broadly similar, from year to year, and were generally very low.

Figure 4.23. ‘Total dose’, in mSv y-1, at Wylfa nuclear power station, 2013 to 2024. (Small doses less than or equal to 0.005mSv are recorded as being 0.005mSv).
Year Dose, mSv y-1
Dose limit 1.0
2013 0.005
2014 0.007
2015 0.013
2016 0.008
2017 0.005
2018 0.006
2019 0.005
2020 0.006
2021 0.005
2022 0.014
2023 0.005
2024 0.008

As in 2023, source specific assessments for a high-rate consumer of locally grown foods, and for a high-rate consumer of fish and shellfish (including external radiation) gave exposure levels that were lower than the ‘total dose’ (Table 4.1). The dose to a high-rate consumer of fish and shellfish (including external radiation) was less than 0.005mSv in 2024 and unchanged from 2023. The dose to a high-rate consumer of locally grown foods was also less than 0.005mSv in 2024 and unchanged from recent years.

4.3.2.2. Gaseous discharges and terrestrial monitoring

Gaseous discharges in 2024 were similar in comparison to those reported in recent years.

The focus of the terrestrial sampling was for the analyses of tritium, carbon-14 and sulphur-35 in milk and crops. Data for 2024 are given in Table 4.13(a). As in 2023, sulphur-35 was not positively detected in milk and, carbon-14 concentrations measured in locally produced milk were just above background levels.

4.3.2.3. Liquid waste discharges and aquatic monitoring

The aquatic monitoring programme consists of sampling of fish and shellfish, and the measurement of gamma dose rates. Samples of sediment, seawater and seaweed are analysed as environmental indicator materials. The results of the programme in 2024 are given in Table 4.13(a) and Table 4.13(b). The data for artificial radionuclides related to the Irish Sea continue to reflect the distant effects of Sellafield discharges. The activity concentrations in 2024 were similar to those in previous years. The reported concentration of technetium-99 in seaweed in 2024 (due to the distant effects of discharges to sea from Sellafield) was lower than levels observed in recent years. Caesium-137 concentrations in sediment have remained low over the last decade (Figure 4.24). Overall, gamma dose rates in 2024 were generally similar to those measured in recent years.

Figure 4.24. Caesium-137 concentration, in Bq kg-1 (dry), in marine sediments near Wylfa nuclear power station between 2013 and 2024.
Year 137Cs concentration Bq Kg-1 (dry)
2013 3.4
2014 3.4
2015 2.7
2016 2.6
2017 3.0
2018 2.6
2019 2.6
2020 2.2
2021 2.1
2022 3.0
2023 2.7
2024 5.8

5. Research and radiochemical production establishments

Highlights

  • ‘total dose’ (research) for the representative person were approximately 2% of the annual dose limit in 2024 (for sites that were assessed)
  • ‘total dose’ (radiochemical production) for the representative person were less than 9% of the annual dose limit in 2024

Dounreay, Highland

  • ‘total dose’ for the representative person was 0.021mSv and decreased in 2024 compared to 2023

Grove Centre, Amersham, Buckinghamshire

  • ‘total dose’ for the representative person was 0.087mSv and decreased in 2024 compared to 2023
  • gaseous discharges of ‘all other radionuclides’ (excluding tritium, radon-222, radionuclides presenting a half-life of less than 2 hours and other alpha-emitting radionuclides) increased in 2024

Harwell, Oxfordshire

  • ‘total dose’ for the representative person was 0.008mSv and increased in 2024 compared to 2023

Winfrith, Dorset

  • ‘total dose’ for the representative person was 0.015mSv and decreased in 2024 compared to 2023

This section considers the results of monitoring near research establishments (Dounreay, Harwell, Winfrith and the former fusion energy research site at Culham) and 1 radiochemical production establishment (Grove Centre, Amersham).

In 2024, gaseous and liquid discharges were below regulated limits for each of the establishments (see Appendix 1, Table A1.1 and Table A1.2). Solid waste transfers in 2024 from NRS Dounreay are given in Appendix 1 (Table A1.4). Data tables and the detailed results of the dose assessments, in Open Document Spreadsheet (ODS) format, are downloadable from the main RIFE page.

5.1 Dounreay, Highland

The Dounreay site was opened in 1955 to develop research reactors. Three reactors were built on the site: the Prototype Fast Reactor, the Dounreay Fast Reactor, and the Dounreay Materials Test Reactor. All 3 reactors are now shut down and undergoing decommissioning.

From 2005, the NDA became responsible for the UK’s civil nuclear liabilities, which included those at Dounreay. Consequently, the 3 existing radioactive waste disposal authorisations were transferred to a new site licensed company (Dounreay Site Restoration Limited, DSRL), before DSRL took over the site management contract. DSRL ownership was transferred to the NDA on 1st of April 2021. On the 1st of April 2023, Dounreay joined with Magnox Limited and SEPA transferred all environmental permits falling under its remit from DSRL to Magnox Limited. On 2nd of April 2024 Magnox Limited changed its company name to NRS Limited.

In 2024, radioactive waste discharges from the Dounreay site were made by Magnox Limited (now known as NRS) under an EASR18 radioactive substances authorisation granted by SEPA.

The quantities of both gaseous and liquid discharges were generally similar to those released in recent years (Appendix 1, Table A1.1 and Table A1.2). Solid waste transfers from Dounreay in 2024 are also given in Appendix 1 (Table A1.4).

The most recent habits survey was conducted in 2018 (Dale and others 2021). This habits survey did not identify any occupancy in the area of Oigin’s Geo (see Figure 5.2), as an external exposure pathway.

In 2013, SEPA granted an authorisation to DSRL for the Low-Level Radioactive Waste Disposal Facility (LLWF) that is located adjacent to the main Dounreay site. The first phase of the disposal site comprised the construction and operation of 2 concrete vaults that began accepting low level radioactive waste and demolition low level waste from the Dounreay site in 2015. The safety case and planning permission allow for 2 additional construction phases, each comprising 2 vaults. Further phases of construction will be dependent on the progress with the decommissioning of the Dounreay site.

There are no authorised routes for liquid or gaseous discharges from the Dounreay LLWF. The facility is designed to contain the radioactive waste over a long time, allowing radioactive decay to occur while the waste remains isolated from the environment.

In June 2024, NRS notified SEPA of possible loss of radioactively contaminated water to the ground from the Carbon Bed Filter (CBF) structure located within the Fuel Cycle Area. NRS’s investigation concluded that there was a small leak from the CBF. NRS has subsequently removed water from the structure and installed level monitoring instrumentation. In July 2025, SEPA issued a regulatory notice requiring NRS to undertake a review of existing groundwater monitoring arrangements, assess compliance with the requirement to dispose of radioactive waste via an authorised route, undertake characterisation to establish the extent of the radioactive contamination and develop a programme for undertaking the appropriate remediation.

In August 2024, NRS notified SEPA that very low levels of radioactivity had been identified in samples taken from a sump collecting water ingress within a non-radioactive facility on the Dounreay site. The arrangements in place at the time involved the water being pumped from the sump and discharged to the marine environment via the non-active drainage system, which is not an authorised route for the disposal of liquid radioactive waste. NRS subsequently undertook work to estimate the annual volume discharged from the sump and the radionuclide components present. Based on this information, SEPA concluded that NRS had contravened a condition of its EASR18 radioactive substances authorisation. At the time of writing SEPA is considering this matter.

5.1.1. Doses to the public

The ‘total dose’ from all pathways and sources of radiation was 0.021mSv in 2024 (Table 5.1), or approximately 2% of the dose limit to members of the public. This is a decrease from 0.028mSv in 2023. The representative person was an adult consuming game meat at high rates (unchanged from 2023). The decrease in ‘total dose’ was mostly due to a lower caesium-137 concentration observed in game meat (venison) in 2024.

The trend in the annual ‘total dose’ over the period 2013 to 2024 is given in

Figure 5.1. Between 2013 to 2015, the change in annual ‘total dose’ was mostly due to the contribution of goats’ milk not being included in the assessment (which had been assessed prior to 2013), as milk samples have not been available in recent years. As in 2024, the significant contributor that influenced the dose was the concentration of caesium-137 found in venison (game) in 2016, 2018, 2021 and 2023.

Figure 5.1. ‘Total dose’, in mSv y-1, at Dounreay, 2013 to 2024.
Year Dose, mSv y-1
Dose limit 1.0
2013 0.012
2014 0.012
2015 0.010
2016 0.058
2017 0.010
2018 0.035
2019 0.010
2020 0.009
2021 0.026
2022 0.010
2023 0.028
2024 0.021

The annual dose to a consumer of terrestrial foodstuffs was 0.015mSv in 2024, or less than 2% of the dose limit for members of the public of 1mSv, and down from 0.017mSv in 2023. As in previous years, adults were identified as the most exposed age group with reason for the decrease in dose was the same as that contributing to the ‘total dose’. The annual dose to a consumer of fish and shellfish, including external exposure from occupancy over local beaches, was lower than the ‘total dose’ in 2024 (0.008mSv) and up from 0.006mSv in 2023. The reason for the increase in dose was mainly due to a higher concentration of plutonium-239+240 observed in mussels in comparison to 2023. The dose (external pathways only) to members of the public visiting Oigin’s Geo, based on previously collected habits data (Papworth, Garrod & Clyne 2014) and 2019 monitoring data, was less than 0.005mSv. The sample species, type and locations are listed in the respective site tables.

Figure 5.2. Monitoring locations at Dounreay, 2024 (not including farms or air sampling locations). The rectangle around the Dounreay site is presented inset.

5.1.2 Gaseous discharges and terrestrial monitoring

In 2024, Magnox Limited and NRS were authorised by SEPA to discharge radioactive gaseous wastes to the local environment via stacks to the atmosphere. The discharges also include a minor contribution from the adjoining reactor site (Vulcan naval reactor test establishment (NRTE)), which is operated by the MOD‘s Submarine Delivery Agency. Monitoring conducted in 2024 included the sampling of air, freshwater, grass, soil and locally grown terrestrial foods including meat and vegetables as well as wild foods. As there are no dairy cattle herds in the Dounreay area, no milk samples were collected from cattle. As in recent years, goats’ milk samples were not sampled, as no milk sample was available in 2024.

The sampling locations for the terrestrial (and marine) monitoring programmes are shown in Figure 5.2. Figures 5.3(a-b) provides time trends of radionuclide discharges (gaseous), which are generally decreasing over the period 2013 to 2024. The sample species, type and locations are listed in the respective site tables. The results for terrestrial samples and radioactivity in air are given in Table 5.2(a) and Table 5.2(c).

Figure 5.3(a). Discharges of gaseous iodine-129, MBq y-1, from Dounreay
Figure 5.3(b). Discharges of gaseous alpha, MBq y-1, from Dounreay, 2013 to 2024.

The concentrations of radionuclides at Dounreay were generally low and relatively similar to those observed in previous years. As in recent years, strontium-90 was positively detected in a few food samples, and iodine-129 concentrations were all reported as less than values in 2024. Activity concentrations in air samples at locations near to the site (Table 5.2(c)) were reported as less than values, apart from gross alpha from the location near Westfield (just above the LoD).

Caesium-137 is likely to be present in terrestrial samples from the Dounreay area due to fallout from weapons testing in the 1960s and from the Chernobyl reactor accident in 1986. As in recent years, caesium-137 was positively detected in venison (24 Bq kg-1) and was slightly lower than that observed in 2023 (34Bq kg-1 in 2023). Unlike 2023, a honey sample was available in 2024 and presented a low concentration of caesium-137 (<1Bq kg-1). Earlier RIFE reports have provided results and interpretation of honey monitoring (for example (Environment Agency, Food Standards Agency, Food Standards Scotland, Natural Resources Wales and others 2018)).

5.1.3. Liquid waste discharges and aquatic monitoring

Low level liquid waste is routed via a Low-Level Liquid Effluent Treatment Plant (LLLETP). The effluent is discharged to sea (Pentland Firth) via a pipeline terminating 600 metres offshore at a depth of about 24 metres. The discharges also include groundwater pumped from the Dounreay shaft, surface water runoff, leachate from the on-site low level solid waste disposal facility (which operated from 1958 to 2005), and a minor contribution from the adjoining reactor site (Vulcan NRTE). Figures 5.3(c-e) provides time trends of liquid radionuclide discharges.

Figure 5.3(c). Discharges of liquid strontium-90, GBq y-1, from Dounreay, 2013 to 2024.
Figure 5.3(d). Discharges of liquid caesium-137, GBq y-1, from Dounreay, 2013 to 2024.
Figure 5.3(e). Discharges of liquid alpha, GBq y-1, from Dounreay, 2013 to 2024.

Routine marine monitoring included sampling of seafood and the measurement of beta and gamma dose rates. A Food and Environment Protection Act (FEPA) Order[footnote 10] exists which prevents the collection of seafood within a defined area around the long sea outfall. Samples can be collected under consent granted in 1997 by the Scottish Office and revised in 2011 by the FSS (then FSA in Scotland).

Cod, crab, mussel and winkle samples were collected from areas along the Caithness coastline. Additionally, sediment, seawater and seaweed were sampled in 2024 as indicator materials. The results for marine samples, and gamma and beta dose rates, are given in Table 5.2(a) and Table 5.2(b). Activity concentrations were generally low in 2024 and similar to those in recent years. Technetium-99 concentrations in seaweed remained at the expected levels for this distance from Sellafield and were similar to those in previous years (Figure 3.10(b)). Figure 5.3(f) also gives time trend information for technetium-99 concentrations (from Sellafield) in seaweed at Sandside Bay (location shown in Figure 5.2), and Burwick. Data indicate a general decline in concentrations over the period at both locations. Caesium-137 concentrations in sediment at Oigin’s Geo (from 2013 to 2019), Sandside Bay and Rennibister (both 2013 to 2024), have generally decrease with variability (Figure 5.3(g)). Overall, gamma dose rates in 2024 were similar to those observed in 2023. As in 2023, beta dose rate measurements were all reported as less than values (Table 5.2(b)) in 2024.

Figure 5.3(f). Concentrations of technetium-99 in seaweed, in Bq kg-1 (fresh), at Sandside Bay and Burwick Pier, 2013 to 2024.
Figure 5.3(g). Concentrations of caesium-137 in sediment, in Bq kg-1 (dry), at Sandside Bay, Rennibister and Oigins Geo, 2013 to 2024.

During 2024, Magnox Limited and NRS continued monitoring of local public beaches, using vehicle mounted detectors, for radioactive fragments in compliance with the requirements of the authorisation granted by SEPA. In 2024, 1 fragment was recovered from Sandside Bay and 6 fragments were recovered from the Dounreay foreshore. The caesium-137 activity measured in the fragment recovered from Sandside Bay was 12kBq (similar to activity levels observed in recent years). Fragments recovered from the Dounreay foreshore ranged from 14kBq to 490kBq.

The Particles Retrieval Advisory Group (Dounreay) (PRAG(D)) are preparing a report, due for release during 2025. Dounreay particle updates are posted on Radioactive particles in the environment around Dounreay - Pre-2023 Data Only and from October 2023 onwards particle find updates can be found here (onshore monitoring of radioactive particles).

The previously conducted offshore survey work provided data on repopulation rates of particles (fragments) to areas of the seabed previously cleared of particles. This work has improved the understanding of particle movements in the marine environment. The Dounreay Particles Advisory Group (DPAG) completed its work following the production of its Fourth Report (Dounreay Particles Advisory Group 2008). Since the work of DPAG[footnote 11] was concluded, PRAG(D) has published reports in 2010 and 2011 (Particles Retrieval Advisory Group (Dounreay) 2010; Particles Retrieval Advisory Group (Dounreay) 2011). In 2016, PRAG(D) published a further report into the retrieval of offshore particles. This was produced following an extensive research and monitoring programme in 2012 (Particles Retrieval Advisory Group (Dounreay) 2016). The report considered the extent and effectiveness of the offshore recovery programme to reduce the numbers of particles. The report concluded that any noticeable change in the rate or radioactive content of the particles arriving on the nearest public beach (Sandside Bay) will take several years to assess and recommended that in the interim the monitoring of local beaches should continue.

In 2007, the FSA reviewed the Dounreay FEPA Order. A risk assessment, that was peer-reviewed by UKHSA, indicated that the food chain risk was very small (Food Standards Agency 2009). The FEPA Order was reviewed with regard to ongoing work to remove radioactive particles from the seabed and the food chain risk. In 2009, the FSA in Scotland (now FSS) announced that the FEPA Order would remain in place and be reviewed again upon completion of the (now completed) seabed remediation work. Following a recommendation in the 2016 PRAG(D) report FSS agreed that the FEPA Order would remain in place and be reviewed following re-evaluation of particle arrival rates.

5.2. Grove Centre, Amersham, Buckinghamshire

The Grove Centre is operated by GE Healthcare Limited, it consists of a range of plants previously used for manufacturing diagnostic imaging products for use in medicine and research, which are now closed and being decommissioned.

The monitoring programme consists of analysis of fish, crops, water, soil and other environmental materials, and measurements of gamma dose rates. The monitoring locations are shown in Figure 5.4. The sample species, type and locations are listed in the respective site tables. The most recent habits survey was undertaken in 2016 (Clyne and others 2017).

Figure 5.4. Monitoring locations near the River Thames, 2024 (not including farms).

5.2.1. Doses to the public

The ‘total dose’ from all pathways and sources of radiation was estimated to be 0.087mSv in 2024 (Table 5.1) or less than 9% of the dose limit to members of the public. This was a decrease from 2023 (0.089mSv). As in recent years, the dominant contribution to ‘total dose’ was from direct radiation from stored radioactive waste. The representative person was a prenatal child of an adult living in the vicinity of the site in 2024 and a change from 2023 (adult living in the vicinity of the site). Exposure from direct radiation varies around the boundary of the Grove Centre and therefore the ‘total dose’ is determined as a cautious upper value. The trend in annual ‘total dose’ over the period 2013 to 2024 is given in Figure 5.5. In 2013, the ‘total dose’ was dominated by direct radiation. The lower values from 2014 onwards are due to changes in working practices for distribution activities, with products spending less time in the dispatch yard – as well as the construction of a shield wall on the western side of a building that contains legacy radioactive wastes. All distribution activity ceased in 2019. Dose from the site is now dominated by radiation from the waste store. The ‘total dose’ is expected to be no more than the conservative estimated value of 0.087mSv. The trends in ‘total dose’ is given in Figure 5.5. The doses are dominated by direct radiation, estimates of which have remained relatively constant in the recent years.

Figure 5.5. ‘Total dose’, in mSv y-1, at the Grove Centre, Amersham, 2013 to 2024.
Year Dose, mSv y-1
Dose limit 1.0
2013 0.22
2014 0.14
2015 0.14
2016 0.15
2017 0.15
2018 0.14
2019 0.14
2020 0.14
2021 0.083
2022 0.086
2023 0.089
2024 0.087

As in recent years, source specific assessments for a high-rate consumer of locally grown foods, for an angler and for a worker at Maple Lodge Sewage Treatment Works (STW), which serves the sewers to which permitted discharges are made, gave exposures that were less than the ‘total dose’ in 2024 (Table 5.1). The dose for a high-rate consumer of locally grown foods was 0.010mSv in 2024 and down from 2023 (0.013mSv). This decrease in dose was mostly due to a lower contribution from the gaseous discharges of radon-222 in 2024. It should be noted that the current assessment methodology uses a conservative dose factor based on this nuclide being in equilibrium with its decay products. As in recent years, the dose to a local angler was less than 0.005mSv in 2024.

The 2016 habits survey at Amersham did not directly identify any consumers of fish, shellfish or freshwater plants. As in previous surveys, however, there were reports of occasional coarse fish and signal crayfish consumption (but no actual consumption rates). To allow for this, a consumption rate of 1kg per year for fish and signal crayfish has been included in the dose assessment for an angler.

The Grove Centre discharges liquid waste to Maple Lodge STW, and the proximity to raw sewage and sludge experienced by sewage treatment workers is a likely exposure pathway (National Dose Assessment Working Group 2004). The dose received by one of these workers was modelled using the methods described in Appendix 3. The dose from a combination of external exposure to contaminated raw sewage and sludge, inadvertent ingestion and inhalation of re-suspended radionuclides was less than 0.005mSv in 2024 and unchanged from recent years.

5.2.2. Gaseous discharges and terrestrial monitoring

The Grove Centre is permitted to discharge gaseous radioactive wastes via stacks on the site. Gaseous discharges of all other radionuclides (excluding tritium, radon-222, radionuclides presenting a half-life of less than 2 hours and other alpha-emitting radionuclides) increased in 2024, in comparison with those in 2023.The results for the terrestrial monitoring for 2024 are given in Table 5.3(a) and Table 5.3(b). As in recent years, sulphur-35 was positively detected in food (wheat and potato), and caesium-137 deposited nuclear fallout was detected in soil near the site in 2024.

5.2.3. Liquid waste discharges and aquatic monitoring

Radioactive liquid wastes are discharged to sewers serving the Maple Lodge STW; treated effluent subsequently enters the Grand Union Canal and the River Colne. The results of the aquatic monitoring programme for 2024 are given in Table 5.3(a). As in recent years, activity concentrations of tritium, iodine-131 and caesium-137 in freshwater were mostly reported as less than values in 2024. Samples of effluent and sludge from Maple Lodge STW were also collected in 2024. The concentration levels observed in these samples were similar to the latest results observed in recent years and iodine-131 was positively detected in the digested sludge collected in 2024.Tritium, gross alpha and gross beta concentrations observed in freshwater were below the investigation levels for drinking water in the Water Supply (Water Quality) (Amendment) 2018 Regulations (retained from the European Directive 2013/51). Gamma dose rates over grass were generally indistinguishable from natural background in 2024 (Table 5.3(b)) and were broadly similar to those measured in recent years.

5.3. Harwell, Oxfordshire

The Harwell site was established in 1946 as the UK’s first Atomic Energy Research Establishment and is situated approximately 5km southwest of the town of Didcot. Since 2015, the Harwell site has been operated by NRS on behalf of the NDA. The Harwell nuclear site forms part of Harwell Campus, a science, innovation and business campus. The nuclear site originally accommodated 14 experimental reactors, most of which have been removed. The fuel has been removed from the remaining 3 reactors, which are now in ‘care and maintenance’. In 2022, the final remediation work was completed for the decommissioned Liquid Effluent Treatment Plant. Radiological sampling to support the Environmental Permit surrender and delicensing of this area is now complete. Once the area is released from radioactive substances regulation, this land will be handed back to the Harwell Science Park for future development.

Other decommissioning work at the Harwell site is underway with a project to transfer nuclear materials away from the site expected to be completed by 2026. Historic wastes are being retrieved from their existing storage locations and repackaged for longer-term storage and eventual disposal. Intermediate level waste from Harwell, Winfrith and Culham will be stored in a designated facility on the Harwell site during a quiescent period of care and maintenance. At the final site clearance stage, the 2 materials test reactors (MTRs), DIDO and PLUTO, are due to be demolished and the remaining radioactive waste transferred to the GDF, when it becomes operational, for final disposal. The most recent habits survey was conducted in 2015 (Clyne, Garrod & Dewar 2016).

5.3.1. Doses to the public

The ‘total dose’ from all pathways and sources of radiation was 0.008mSv in 2024 (Table 5.1), which was less than 1% of the dose limit to members of the public and increased from 2023 (<0.005mv). The increase in dose was mainly due to a higher estimate of direct radiation from the site. The representative person was an adult living near the site. This is a change from 2023 (adult spending time over sediments). The trend in annual ‘total dose’ over the period 2013 to 2024 is given in Figure 5.6. The ‘total dose’ remained broadly similar, from year to year (up to 2016), and were low. The increase in ‘total dose’ in 2017 (from 2016), and then decrease in 2018, was attributed to changes in the estimate of direct radiation from the site.

Figure 5.6. ‘Total dose’, in mSv y-1, at Harwell, 2013 to 2024. (Small doses less than or equal to 0.005mSv are recorded as being 0.005mSv).
Year Dose, mSv y-1
Dose limit 1.0
2013 0.010
2014 0.016
2015 0.017
2016 0.015
2017 0.046
2018 0.028
2019 0.010
2020 0.008
2021 0.005
2022 0.005
2023 0.005
2024 0.008

As in recent years, source specific assessments for a high-rate consumer of terrestrial foods, and for an angler, gave exposures that were less than 0.005mSv in 2024 (Table 5.1).

5.3.2. Gaseous discharges and terrestrial monitoring

Gaseous wastes are discharged via stacks to the local environment. As in previous years, discharges of radioactive wastes continued at very low rates. The terrestrial monitoring programme sampled milk, fruit and cereal. The results of the terrestrial monitoring programme in 2024 are shown in Table 5.4. As in recent years, tritium and caesium-137 concentrations in terrestrial samples were all reported as less than values in 2024.

5.3.3. Liquid waste discharges and aquatic monitoring

Permitted liquid discharges from Harwell are discharged to sewers serving the Didcot STW; treated effluent subsequently enters the River Thames at Long Wittenham.

Permitted discharges of surface water drainage from the Harwell site are made via the Lydebank Brook. As in recent years, discharges to Lydebank Brook were very low. Figure 5.7 shows trends of discharges over time (2013 to 2024) for cobalt-60 and caesium-137 to sewer. There was an overall reduction in the discharges over the whole period and very low discharges in most recent years.

Year 60Co discharge, MBq y-1
2013 0.52
2014 1.6
2015 1.0
2016 0.039
2017 0.29
2018 0.23
2019 0.45
2020 0.15
2021 0.25
2022 0.22
2023 0.13
2024 0.13
Year 137Cs discharge, MBq y-1
2013 35
2014 35
2015 7.7
2016 0.11
2017 2.7
2018 3.6
2019 3.6
2020 0.24
2021 0.17
2022 0.13
2023 0.10
2024 0.15

The aquatic monitoring programme is directed at consumers of fish and occupancy (sediment and freshwater samples) close to the liquid discharge point. Due to on-going access issues at Day’s Lock, the Environment Agency have replaced this sampling location with River Thames above Shillingford. The results of the aquatic monitoring programme in 2024 are shown in Table 5.4. As in recent years, concentrations of tritium, cobalt-60 and caesium-137 in freshwater were reported as less than values. The caesium-137 concentration in sediment continued to be slightly enhanced above background levels in 2024. As in 2023, plutonium-239+240 and americium-241 were positively detected at low levels in the sediment collected near Sutton Courtenay in 2024.

5.4. Winfrith, Dorset

The Winfrith site is located near Winfrith Newburgh, Dorset. It was established in 1957 as an experimental reactor research and development site. Since 2015, the Winfrith site has been operated by NRS on behalf of the NDA. At various times, there have been 9 research and development reactors. The last operational reactor at Winfrith closed in 1995. Seven of the reactors have been decommissioned. The final 2; steam generating heavy water and ‘Dragon’ (high temperature gas-cooled) reactors and supporting site facilities, are in the process of being decommissioned. It is the end state intention of NRS to return most of the land to a brownfield heathland site with public access.

NRS Winfrith is located adjacent to the Tradebe-Inutec site. Tradebe-Inutec is an independent nuclear operator (see section 7.3). NRS Winfrith and Tradebe-Inutec undertake separate site environmental monitoring programmes as required by their respective environmental permits. However, in this report, NRS Winfrith and Tradebe-Inutec are considered together for the purposes of environmental monitoring because, with the exclusion of their liquid discharges (which discharge to different geographic areas), their operational activities and gaseous discharges impact on the same local area.

The most recent habits survey (covering both the NRS and Tradebe-Inutec sites) was conducted in 2019 (Moore, Clyne & Greenhill 2020).

5.4.1. Doses to the public

In 2024, the ‘total dose’ from all pathways and sources of radiation was 0.015mSv (Table 5.1), or less than 2% of the dose limit to members of the public. This is a decrease from 0.054mSv in 2023. The decrease in ‘total dose’ was mainly attributed to a lower estimate of direct radiation from the site, compared to that in 2023. As in recent years, the ‘total dose’ was almost entirely attributed to the direct radiation from the NRS Winfrith site in 2024 (Table 1.1). The representative person was an adult living near the site and unchanged from recent years. Trends in annual ‘total dose’ over the period between 2013 and 2024 are shown in Figure 5.8. Up until 2014, ‘total dose’ remained broadly similar and were generally very low. The variations observed from 2015 are mainly due to changes in the estimates of direct radiation from the site. The increase in estimates of total dose at NRS Winfrith when compared to the previous reporting period, is attributed to the extent of the decommissioning work undertaken at the site in the recent years, including removal, temporary storage, and transfer of legacy wastes for off-site disposal. The specific waste transfer activities that occurred during 2024, are time limited in nature, and form part of the routine operational work required to secure the safe decommissioning of the site. Estimates of ‘total dose’ will fluctuate with operational decommissioning work demands as the site proceeds through to the final stage of decommissioning and all radioactive waste management activities cease.

Figure 5.8. ‘Total dose’, in mSv y-1, at Winfrith, 2013 to 2024. (Small doses less than or equal to 0.005mSv are recorded as being 0.005mSv).
Year Dose, mSv y-1
Dose limit 1.0
2013 0.005
2014 0.005
2015 0.014
2016 0.019
2017 0.038
2018 0.027
2019 0.027
2020 0.014
2021 0.006
2022 0.028
2023 0.054
2024 0.015

As in recent years, the dose to a high-rate consumer of locally grown food was less than 0.005mSv in 2024. The dose to a high-rate consumer of fish and shellfish was less than 0.005mSv a decrease from 0.010mSv in 2023. The decrease in dose was mostly due to a lower limit of detection value for americium-241 in fish (skates and rays) being used in the assessment.

5.4.2. Gaseous discharges and terrestrial monitoring

At NRS Winfrith, gaseous radioactive waste is discharged via various stacks to the local environment. As in previous years, discharges were very low in 2024. In RIFE this report, gaseous discharges from NRS Winfrith and Tradebe-Inutec are considered together for the purposes of environmental monitoring because their operational activities and gaseous discharges impact on the same local area.

The focus of the terrestrial sampling was the analyses of tritium and carbon-14 in milk and crops. Local freshwater, grass and sediment samples were also analysed. Sampling locations at Winfrith are shown in Figure 5.9. The sample species, type and locations are listed in the respective site tables. Data for 2024 are given in Table 5.5(a). Results from terrestrial samples provide little indication of an effect due to gaseous discharges. As in recent years, the carbon-14 concentrations in locally produced milk were above values used to represent background concentrations Tritium concentrations in surface water were similar to those observed in previous years. Tritium, gross alpha, and gross beta concentrations in freshwater were below the investigation levels for drinking water in the Water Supply (Water Quality) (Amendment) 2018 Regulations (retained from the European Directive 2013/51).

Figure 5.9. Monitoring locations at Winfrith, 2024 (not including farms).

5.4.3. Liquid waste discharges and aquatic monitoring

Liquid wastes, from the NRS Winfrith site, are disposed via a pipeline to deep water in Weymouth Bay. As in previous years, discharges continued at very low rates in 2024 (all reported as <1% of the annual limit).

Figure 5.10 shows trends of liquid discharges over time (2013 to 2024) for tritium and alpha-emitting radionuclides. In recent years, alpha-emitting radionuclide discharges have decreased since the peak observed in 2013. In comparison, tritium discharges have varied more between years, with periodic peaks in releases, due to operations at Tradebe-Inutec, but have also generally declined since 2015 and ceased in 2019.

Year Tritium discharge, TBq y-1
2013 9.8
2014 1.0
2015 11
2016 7.1
2017 1.0
2018 1.9
2019 0.00063
2020 0.028
2021 0.0008
2022 0.00036
2023 0.00022
2024 0.00056
Year Alpha discharge, MBq y-1
2013 980
2014 11
2015 4.3
2016 4.7
2017 7.6
2018 4.0
2019 1.0
2020 0.81
2021 0.76
2022 0.53
2023 0.50
2024 0.55

Analyses of seafood and marine indicator materials and measurements of external radiation over muddy intertidal areas were conducted in 2024. These are primarily to determine the effects of liquid discharges from the NRS Winfrith site and, to a lesser extent, historical (pre-2019) liquid discharges from Tradebe-Inutec. The results of the aquatic monitoring programme and measurements of external radiation in 2024 are shown in Table 5.5(a) and Table 5.5 (b) respectively. Concentrations of radionuclides in the marine environment were low and similar to those in previous years. Unlike in 2023, caesium-137 was positively detected (albeit at low levels) in the fish sample collected from Weymouth Bay (skates and rays). Gamma dose rates in 2024 were generally similar to those measured in 2023 (where comparison could be made).

5.5. Culham, Oxfordshire

Culham Centre for Fusion Energy (CCFE), operated by the United Kingdom Atomic Energy Authority (UKAEA), is the UK’s national laboratory for fusion research. CCFE hosts and is responsible for the operation of 2 experimental fusion reactors: the Joint European Torus (JET) and the Mega Amp Spherical Tokamak (MAST) Upgrade. The JET concluded its operation in December 2023.

The Culham site also operates several other facilities to support fusion energy and related technologies and should host commercial fusion developers to become a fusion cluster hub in the future.

An annual ‘total dose’ is not determined at this site in this report because an integrated habits survey has not been undertaken. The source specific dose (including tritium and caesium-137), from using the River Thames directly as a source of drinking water, downstream of the discharge point at Culham, was estimated to be less than 0.005mSv in 2024 (Table 5.1) a decrease from 0.006mSv in 2023. The main reason for the decrease in dose was the use of a lower limit of detection for tritium observed in the freshwater samples collected from the River Thames downstream of the discharge point in the calculation of the dose.

Monitoring of soil and grass around Culham and of sediment and water from the River Thames was undertaken in 2024. Locations and data are shown in Figure 5.4 and Table 5.6, respectively. Historically, the main effect of the site’s operation was the increased tritium concentrations found in grass collected near the site perimeter. As in recent years, concentrations of tritium in all samples were reported as less than values. The reported caesium-137 concentration in the downstream sediment (14Bq kg-1) was estimated to be lower in 2024, in comparison to that in recent years (<26 and 26Bq kg-1 in 2023 and 2022, respectively). Caesium-137 concentrations in the River Thames sediment are not attributable to Culham but were most likely due to past discharges from Harwell and fallout from Chernobyl and nuclear weapons testing.

6. Defence establishments

Highlights

  • ‘total dose’ for the representative person were approximately 6% of the dose limit for all sites assessed

Aldermaston and Burghfield, Berkshire

  • ‘total dose’ for the representative person was 0.010mSv and decreased in 2024 compared to 2023

Barrow, Cumbria

  • ‘total dose’ for the representative person was 0.061mSv and increased in 2024 compared to 2023

Derby, Derbyshire

  • ‘total dose’ for the representative person was 0.007mSv and increased in 2024 compared to 2023

Devonport, Devon

  • ‘total dose’ for the representative person was less than 0.005mSv and unchanged in 2024 compared to that in 2023
  • gaseous discharges of argon-41 decreased in 2024

Faslane and Coulport, Argyll and Bute

  • ‘total dose’ for the representative person was 0.005mSv and increased in 2024 compared to that in 2023

Rosyth, Fife

  • ‘total dose’ for the representative person was 0.011mSv and increased in 2024 compared to that in 2023
  • gaseous discharges of carbon-14 increased in 2024

Vulcan Naval Reactor Test Establishment, Highland

  • gaseous discharges of ‘all other radionuclides’ decreased in 2024

This section considers the results of monitoring undertaken by the Environment Agency, FSA, FSS and SEPA, near 8 defence-related establishments in the UK. In addition, the MOD undertakes monitoring at other defence sites where radiological contamination may occur.

In 2024, gaseous and liquid discharges were below regulated limits for each of the defence establishments, see Appendix 1, Table A1.1 and Table A1.2. Solid waste transfers in 2024 from nuclear establishments in Scotland (Coulport, Faslane, Rosyth and Vulcan) are also given in Appendix 1 (Table A1.4). Data tables and the detailed results of the dose assessments, in Open Document Spreadsheet (ODS) format, are downloadable from the main RIFE page.

6.1. Aldermaston and Burghfield

The Atomic Weapons Establishment (AWE) has 2 sites located in Berkshire: AWE Aldermaston and AWE Burghfield. AWE Aldermaston provides and maintains the fundamental components of the UK’s nuclear deterrent, including component manufacture and radioactive waste management activities. The day-to-day operations and the maintenance of the UK’s nuclear stockpile are managed, on behalf of the MOD, by AWE plc (which is a non-departmental public body, wholly owned by the MOD). AWE Burghfield is responsible for the final assembly and maintenance of warheads whilst in service, as well as their decommissioning. Gaseous and liquid discharges of radioactive waste to the environment are regulated by the Environment Agency, permitting discharges of low concentrations of radioactive waste.

The most recent habits survey to determine the consumption and occupancy rates by members of the public in the vicinity of the sites was undertaken in 2022 (Greenhill and others 2023).

6.1.1. Doses to the public

In 2024, the ‘total dose’ from all pathways and sources of radiation was 0.010mSv (Table 6.1), or 1% of the dose limit to members of the public. This is a small decrease from 0.011mSv in 2023. As in recent years, the representative person was an adult consuming game meat at high rates.

As in recent years, source specific assessments for high-rate consumers of locally grown foods, for sewage workers, and for anglers gave exposures that were less than 0.005mSv in 2024 (Table 6.1). Estimates of activity concentrations in fish have been based on shellfish samples from the aquatic monitoring programme for the dose determination. A low consumption rate of 1kg per year for fish has been included in the dose assessment for anglers.

6.1.2 Gaseous discharges and terrestrial monitoring

Permitted discharges of gaseous radioactive waste are made via stacks from facilities at AWE Aldermaston and AWE Burghfield. Samples of milk, terrestrial foodstuffs, grass and soil were taken from locations close to the sites (Figure 5.4) and the results of the terrestrial monitoring in 2024 are given in Table 6.2(a). In 2024, tritium concentrations and other radionuclides in foodstuffs, including milk, were very low or reported as less than values. Caesium-137 concentrations were positively detected in soil samples and were generally similar to those measured in previous years. Caesium-137 concentrations in all food and grass samples were reported as less than values in 2024. Uranium isotopes in milk were not positively detected in 2024, indicating that uranium concentrations were lower than in 2023. Natural background or fallout concentrations from global nuclear weapons testing would have made a significant contribution to the measured values.

6.1.3. Liquid waste discharges and aquatic monitoring

Permitted discharges of radioactive liquid effluent are made to the sewage treatment works at Silchester (Figure 5.4), and to the Aldermaston Stream from AWE Aldermaston. A time-series trend of generally decreasing tritium discharges from AWE Aldermaston, over the period 2013 to 2024, is shown in Figure 6.1. Tritium discharges have declined more significantly, over a longer period in comparison to the last decade (Environment Agency, Food Standards Agency, Food Standards Scotland, Northern Ireland Environment Agency and others 2018). The longer-term decline in discharges is partly due to the reduction of historical groundwater contamination by radioactive decay and dilution by natural processes. Discharges of radioactive liquid effluent from AWE Burghfield are made to a sewage treatment works located on the site. Environmental monitoring of the River Thames, at Pangbourne and Mapledurham, has continued to assess the effect of historical discharges.

Year Tritium discharge, GBq -1
2013 0.63
2014 0.67
2015 0.11
2016 0.45
2017 0.51
2018 0.38
2019 0.41
2020 0.30
2021 0.35
2022 0.26
2023 0.28
2024 0.26

Activity concentrations for freshwater, fish, sediment samples, including gully pot sediments from road drains, and measurements of gamma dose rates, are given in Table 6.2(a) and Table 6.2(b). The concentrations of artificial radioactivity detected in the Thames catchment were very low in 2024 and generally similar to those in recent years. Activity concentrations of artificial radionuclides in shellfish were very low in 2024 and similar to those reported in recent years. The results from analyses of caesium-137 and uranium activity concentrations in River Kennet sediments were broadly consistent with those observed in recent years. As in 2023, tritium concentrations in freshwater samples were all reported as less than values, and caesium-137 concentrations in gully pot sediments were broadly similar to those measured in 2023. Gross alpha and beta activities in freshwater samples were below the investigation levels for drinking water in the Water Supply (Water Quality) (Amendment) 2018 Regulations (based upon the European Directive 2013/51). Gamma dose rates were below or close to natural background.

6.2. Barrow, Cumbria

At Barrow, BAE Systems Marine Limited builds, tests and commissions new nuclear-powered submarines. Gaseous discharges were reported as nil, and liquid discharges of tritium, carbon-14 and cobalt-60 to sewer were all very low (<1% of the annual limit) in 2024. The most recent habits survey was undertaken in 2012 (Garrod CJ and others 2013b).

The ‘total dose’ from all pathways and sources of radiation was 0.061mSv (Table 6.1) in 2024, or approximately 6% of the dose limit to members of the public. This is an increase from 0.042mSv in 2023. Most of this dose was due to the effects of Sellafield discharges. As in recent years, the representative person was an adult living on a local houseboat. The increase in ‘total dose’ was primarily due to an increase in the gamma dose rate measured over a different substrate (mud and sand) at Roa Island. The trend in ‘total dose’ over the period 2013 to 2024 is given in Figure 6.2, ranging from a 0.030 to 0.082mSv.

Figure 6.2. ‘Total dose’, in mSv y-1, at Barrow (2013 to 2024). Doses are largely due to Sellafield discharges.

Year Dose, mSv y-1
Dose limit 1 .0
2013 0.076
2014 0.055
2015 0.051
2016 0.082
2017 0.074
2018 0.046
2019 0.057
2020 0.061
2021 0.044
2022 0.030
2023 0.042
2024 0.061

As in 2023, source specific assessments for a person living on a local houseboat gave exposures that were less than the ‘total dose’ in 2024 (Table 6.1). The assessment for a high-rate consumer of locally grown food (<0.005mSv) was lower than in 2023 (0.013mSv). The apparent decrease in dose was attributed to the exclusion of americium-241 activity concentrations in the 2024 terrestrial assessment. In line with the dose assessment methodology used in the RIFE reports (as set out in Section 2), americium-241 was excluded in the 2024 assessment as it was not positively detected in any terrestrial sample. No assessment of seafood consumption was undertaken in 2024 due to the absence of relevant monitoring data. However, the dose from seafood consumption is less important than that from external exposure on a houseboat (Environment Agency, Food Standards Agency, Northern Ireland Environment Agency and others 2014).

The FSA’s terrestrial monitoring is limited to vegetable and grass (or silage) sampling. The Environment Agency monitors gamma dose rates and analysis of sediment samples from local intertidal areas and is directed primarily at the far-field effects of Sellafield discharges. The results are given in Table 6.3(a) and Table 6.3(b). No effects of discharges from Barrow were apparent in the concentrations of radioactivity in vegetables and silage, with most results reported as less than values. In 2024, the reported gross beta concentration, due to the far-field effects of Sellafield discharges, in Walney Channel sediment was slightly higher than in 2023. The gamma dose rates in intertidal areas near Barrow in 2023 are given in Table 6.3(b) and Table 3.9. As in previous years, gamma dose rates were enhanced above those expected due to natural background and generally higher than those measured in 2023. Any enhancement above natural background is most likely due to the far-field effects of historical discharges from Sellafield.

6.3. Derby, Derbyshire

Rolls-Royce Submarines Limited (RRSL) a subsidiary of Rolls-Royce plc, carries out design, development, testing and manufacture of reactor cores for nuclear-powered submarines at its 2 adjacent sites in Raynesway in Derby. Small discharges of liquid effluent are made via the Megaloughton Lane STW to the River Derwent and very low concentrations of alpha activity are present in releases to the atmosphere. Other wastes are disposed of by transfer to other sites, for example, at a permitted solid waste disposal site or by incineration. The most recent habits survey was undertaken in 2021 (Greenhill, Clyne & Moore 2022).

6.3.1. Doses to the public

The ‘total dose’ from all pathways and sources of radiation was 0.007mSv in 2024 (Table 6.1), which is less than 1% of the dose limit to members of the public. This is a small increase from 0.006mSv in 2023. The representative person was a child living near the site in 2024 and was unchanged from 2023. The increase in ‘total dose’ was attributed to a higher estimate of direct radiation from the site. Source specific assessments for consumption of fish, crustaceans and drinking river water at high-rates, and for spending time over river-washed areas gave exposures that were less than 0.005mSv in 2024 (Table 6.1).

Results of the routine monitoring programme at Derby are given in Table 6.3(a). Concentrations of uranium in samples taken around the site in 2024 were generally similar to those in previous years. More detailed analysis in previous years has shown the activity as being consistent with natural sources. The gross alpha and beta activities in water samples from the River Derwent were less than the investigation levels for drinking water in the Water Supply (Water Quality) (Amendment) 2018 Regulations (based upon the European Directive 2013/51). Caesium-137 detected in sediments from local water courses was most likely from historic fallout from overseas sources, such as nuclear weapons testing.

Table 6.3(a) also includes analytical results for a water sample taken from Fritchley Brook, downstream of Hilts Quarry, near Crich in Derbyshire. RRSL formerly used the quarry for the controlled burial of solid low level radioactive waste. Concentrations of uranium isotopes detected in the sample in 2024 were broadly similar to those reported elsewhere in Derbyshire (Table 8.7).

6.4. Devonport, Devon

The Devonport Royal Dockyard consists of 2 parts and is operated by His Majesty’s Naval Base (HMNB) (owned and operated by the MOD) and Devonport Royal Dockyard Limited (owned by Babcock International Group plc). Devonport Royal Dockyard refits, refuels, repairs and maintains the Royal Navy’s nuclear-powered submarine fleet. Gaseous and liquid discharges of radioactive waste to the environment are regulated by the Environment Agency.

The most recent habits survey to determine the consumption and occupancy rates by members of the public was undertaken in 2017 (Moore and others 2018). The routine monitoring programme in 2024 consisted of measurements of gamma dose rate and analysis of grass, vegetables, fish, shellfish and other environmental indicator materials (Table 6.3(a) and Table 6.3(b)).

6.4.1. Doses to the public

The ‘total dose’ from all pathways and sources of radiation was less than 0.005mSv in 2024 (Table 6.1), which was less than 0.5% of the dose limit, and unchanged from 2023. The representative person was an adult consuming locally collected marine plants at high rates, who also consumed fish (which largely determined the exposure) and spent time on intertidal areas. The trend in annual ‘total dose’ at Devonport remains less than 0.005mSv (Environment Agency, Food Standards Agency, Food Standards Scotland, Northern Ireland Protection Agency and others 2019).

As in recent years, source specific assessments for a high-rate consumer of locally grown food (including doses from external and inhalation from gaseous discharges), for fish and shellfish consumers, and for an occupant of a houseboat, gave exposures that were also less than 0.005mSv in 2024 (Table 6.1).

6.4.2. Gaseous discharges and terrestrial monitoring

Permitted discharges of gaseous radioactive waste at Devonport are made to the atmosphere.

In 2024, gaseous discharges of argon-41 decreased in comparison to those reported in 2023. Terrestrial samples (grass and onions) were analysed for several radionuclides. Activity concentrations in terrestrial samples were reported as less than values in 2024.

6.4.3. Liquid waste discharges and aquatic monitoring

Permitted discharges of liquid radioactive waste are made to the Hamoaze, which is part of the Tamar estuary and to the local sewer.

The trends of tritium and cobalt-60 discharges over time (2013 to 2024) are given in Figure 6.3. The main contributor to the variations in tritium discharges over time has been the re-fitting of Vanguard class submarines. These submarines have a high tritium inventory as they do not routinely discharge primary circuit coolant until they undergo refuelling at Devonport. Cobalt-60 discharges have declined more significantly than tritium, since the early 2000s (Environment Agency, Food Standards Agency, Food Standards Scotland, Northern Ireland Environment Agency and others 2018). The underlying reason for the overall decrease in cobalt-60 discharges over nearly 3 decades has been the improvement in submarine reactor design so that less cobalt-60 was produced during operation, and therefore less was released during submarine maintenance operations.

Year Tritium discharge, TBq y-1
2013 0.086
2014 0.022
2015 0.048
2016 0.018
2017 0.029
2018 0.012
2019 0.0050
2020 0.0084
2021 0.011
2022 0.0024
2023 0.0029
2024 0.020
Year 60Co discharge, GBq y-1
2013 0.060
2014 0.025
2015 0.035
2016 0.039
2017 0.028
2018 0.016
2019 0.0047
2020 0.0032
2021 0.0026
2022 0.0025
2023 0.0018
2024 0.0031

As in 2023, concentrations of tritium and cobalt-60 in marine samples were reported as less than values in 2024. Low caesium-137 concentrations, likely to originate from other sources (such as nuclear weapons testing), were measured in sediment samples. Carbon-14 concentrations in seafood species were generally similar to those in previous years. The seaweed and sewage sludge samples contained concentrations of iodine-131 in 2024. These were most likely to have originated from the therapeutic use of this radionuclide in local hospitals. Gamma dose rates in the vicinity of Devonport in 2024 were similar to those in recent years and reflect the local effects of enhanced background radiation from natural sources.

6.5. Faslane and Coulport, Argyll and Bute

The HMNB Clyde establishment consists of the naval base at Faslane and the armaments depot at Coulport. Babcock Marine, a subsidiary of Babcock International Group plc, operates HMNB Clyde, Faslane in partnership with the MOD. However, the MOD remains in control of the undertaking, through the Naval Base Commander, Clyde (NBC Clyde) in relation to radioactive waste disposal. MOD through NBC Clyde also remains in control of the undertaking at Coulport although many of the activities undertaken at Coulport have been outsourced to an industrial alliance comprising of AWE plc, Babcock and Lockheed Martin UK (known as ABL).

Discharges of liquid radioactive waste into the Gare Loch from Faslane and the discharge of gaseous radioactive waste in the form of tritium to the atmosphere from Coulport, are made under Letters of Agreement (LoA) between SEPA and the MOD. SEPA completed its determination of the application submitted in 2019 for a revised LoA. The new LoA was issued effective 1 January 2025 and includes provision for discharges from a new facility, known as the Nuclear Support Hub (NSH), at Faslane.

Construction of the NSH is complete and commissioning of the NSH will continue in 2025.

In 2024, gaseous tritium discharges (from Coulport) and liquid discharges (from Faslane) were broadly similar, in comparison to those releases in recent years (see Appendix 1, Table A1.1 and Table A1.2, respectively).

The disposal of solid radioactive waste from each site is made under a separate LoA between SEPA and the MOD. Solid waste transfers in 2024 are given in Appendix 1 (Table A1.4).

The most recent habits survey to determine the consumption and occupancy rates by members of the public was undertaken in 2023 and available from SEPA by emailing RSEnquiries@sepa.org.uk.

The ‘total dose’ from all pathways and sources of radiation was 0.005mSv in 2024 (Table 6.1), which was 0.5% of the dose limit to members of the public. This is a small increase from less than 0.005mSv in 2023. The representative person was an adult consuming fish at high rates and unchanged from 2023. The apparent increase in dose was attributed to the inclusion of americium-241 activity concentrations in seafood in the 2024 assessment. In line with the dose assessment methodology used in the RIFE reports (as set out in Section 2), americium-241 was included in the 2024 assessment because americium-241 was positively detected in sediment samples. Activity concentrations in fish (not collected in recent years) were estimated using reported environmental fish data in 2024, sampled outside the aquatic habits survey area of this site, but within the Firth of Clyde. The assessment of this ‘total dose’ was therefore highly conservative, due to the assumption of fish concentration data. In 2024, the source specific assessment for a high-rate consumer of shellfish, which is based on limited data, gave an exposure of 0.006mSv, a small increase from 2023 (less than 0.005mSv). The main reason for this increase in dose was the same as for the ‘total dose’. The dose to a consumer of locally grown food, was less than 0.005mSv and unchanged from 2023.

The routine marine monitoring programme consisted of the analysis of shellfish, seawater, seaweed and sediment samples, and gamma dose rate measurements. Terrestrial monitoring included meat, domestic fruit, honey, water, grass and soil sampling. The results in 2024 are given in Table 6.3(a) and Table 6.3(b) and were generally similar to those in recent years. Caesium-137 was positively detected at a low concentration in honey (as in recent years). Radionuclide concentrations were generally reported as less than values in 2024. Caesium-137 concentrations in sediment and soil are consistent with the distant effects of discharges from Sellafield, fallout from Chernobyl and nuclear weapons testing.

Gamma dose rates measured in the surrounding area were difficult to distinguish from natural background (Table 6.3(b)). The tritium, gross alpha and gross beta concentrations were much lower than the investigation levels in the Water Supply (Water Quality) (Amendment) 2018 Regulations (retained from the European Directive 2013/51).

6.6. Rosyth, Fife

The Rosyth naval dockyard is located on the north bank of the River Forth in Fife, 3km west of the Forth Road Bridge and some 50km from the mouth of the Firth of Forth. It is sited on reclaimed land, with reclamation completed in 1916. From 1916, the site was known as HM Dockyard Rosyth and activities conducted there included refitting and maintaining warships.

In 1997, Rosyth Royal Dockyard Limited (RRDL), a wholly owned subsidiary of Babcock International Group Marine Division, was set up to be responsible for the decommissioning of the dockyard site and the management of radioactive waste that had arisen from the re-fitting of nuclear submarines which ended in 2003. Site decommissioning started in 2006 and has mainly been completed, except for some small areas of the site where facilities are required to continue managing radioactive wastes.

The MOD sold the site to Babcock International Group Marine Division who now manage and operate the site. However, radioactive waste that was generated by the site, to support the nuclear submarine fleet, is owned by the MOD. Therefore, the MOD has entered into a contract with RRDL to manage all radioactive waste on the dockyard site. As the radioactive waste owner, the MOD maintains an overview of procedures to ensure RRDL fully complies with the terms and conditions of its contract.

In 2016, SEPA granted RRDL an authorisation (under RSA 93) to dispose of radioactive waste arising on the Rosyth dockyard site. This allows RRDL to dispose of LLW that arises from the decommissioning of the Rosyth premises, from former submarine re-fitting operations and from waste transferred from the MOD from the dismantling of the 7 redundant nuclear submarines currently stored afloat at the dockyard site. The authorisation was transitioned to a permit under the Environmental Authorisations (Scotland) Regulations 2018 (EASR18) with a new permit being issued in March 2019. In 2023, RRDL applied for a permit variation to allow the management of ILW from the dismantling of the 7 submarines stored at the dockyard. A Letter of Approval (LoA) (effective from 2016) to the MOD allows the transfer of LLW from the 7 nuclear submarines berthed at the Rosyth dockyard site to RRDL. Granting of the LoA and new authorisation to RRDL has permitted the start of the MOD submarine dismantling programme at Rosyth. Work to dismantle and remove radioactive and conventional wastes from each submarine and subsequently clean up the Rosyth site is expected to take up to 15 years to complete. The LoA is being transitioned to replicate an EASR18 permit in line with the recently revised Memorandum of Understanding between SEPA and the MOD.

The most recent habits survey was undertaken in 2022. Copies of the most recent habits survey are available from SEPA by emailing RSEnquiries@sepa.org.uk.

The ‘total dose’ from all pathways and sources of radiation was 0.011mSv in 2024 (Table 6.1), which is approximately 1% of the dose limit to members of the public. In 2024, the representative person was an adult consuming crustacean shellfish at high rates and unchanged from 2023. The increase in ‘total dose’ was attributed to an increase in the gamma dose rate measured over sediments in 2024. The source specific assessment for marine pathways (fishers and beach users) was estimated to be 0.008mSv in 2024 (an increase from 0.006mSv in 2023). The reason for the increase in dose was the same as that contributing to the maximum ‘total dose’.

The gaseous and liquid discharges from Rosyth in 2024 are given in Appendix 1 (Table A1.1 and Table A1.2, respectively), and solid waste transfers in Table A1.4. Liquid wastes are discharged via a dedicated pipeline to the Firth of Forth. Gaseous discharges of carbon-14 increased in 2024 in comparison to that in 2023.

The direct radiation from the site was less than 0.001mSv in 2024 (Table 1.1). This was unchanged from 2023. This value of direct radiation is based upon actual measurements and a more representative background radiation measurement location.

SEPA’s routine monitoring programme included analysis of shellfish, environmental indicator materials and measurements of gamma dose rates in intertidal areas. Results are shown in Table 6.3(a). The radioactivity concentrations in freshwater measured were low in 2024, and similar to those observed in recent years, and in most part due to the combined effects of Sellafield, weapon testing and Chernobyl. Gamma dose rates were slightly higher in 2024 than in 2023 but were difficult to distinguish from natural background at all measurement locations.

6.7 Vulcan NRTE, Highland

The Vulcan Naval Reactor Test Establishment (NRTE) is operated by the Submarine Delivery Agency, part of the MOD, and its purpose was to prototype submarine nuclear reactors. It is located adjacent to the Dounreay site, and the impact of its discharges is considered along with those from Dounreay (in Section 5). The transfer of solid and aqueous waste to NRS Dounreay and the disposal of gaseous waste are made under a LoA between SEPA and the MOD.

Ownership of the site will be transferred from MOD to the NDA for decommissioning once operations have been completed (and subject to regulatory approval). The transfer will not be completed until at least April 2027.

Gaseous discharges, and solid waste transfers, from Vulcan NRTE in 2024 are given in Appendix 1 (Table A1.1 and Table A1.4, respectively). The gaseous discharges of ‘All other radionuclides’ decreased in 2024 in comparison to those in 2023, due to a minor change in reporting methodology.

7. Industrial, solid waste disposal, legacy and other non-nuclear sites

Highlights

  • doses (dominated by the effects of legacy discharges from other sources) increased at the Low Level Waste Repository in 2024
  • doses at solid waste disposal sites were less than 0.5% of the dose limit in 2024
  • doses (dominated by the effects of naturally occurring radionuclides from legacy discharges) decreased at Whitehaven in 2024 compared to 2023

This section considers the results of monitoring by the Environment Agency, FSA, FSS, NRW and SEPA for industrial, solid waste disposal, legacy and other non-nuclear sites that may have introduced radioactivity into the environment:

  • the main disposal site for solid radioactive wastes in the UK, at the LLWR in Cumbria, as well as a recycling facility and other solid waste disposal sites that received small quantities of solid wastes
  • one legacy site in England, near Whitehaven, Cumbria, which was used to manufacture phosphoric acid from imported phosphate ore
  • two legacy sites in Scotland, at Dalgety Bay, Fife, and Kinloss, Moray
  • other non-nuclear sites

Data tables and the detailed results of the dose assessments, in Open Document Spreadsheet (ODS) format, are downloadable from the main RIFE page.

7.1. Low Level Waste Repository, Cumbria

The LLWR is the UK’s national facility for the disposal of lower activity waste and is located on the west Cumbrian coast, southeast of Sellafield. The main function of the LLWR is to receive low activity solid and non-aqueous liquid radioactive wastes from all UK nuclear sites (except Dounreay, where the adjacent disposal facility began accepting waste in 2015) and many non-nuclear sites. Where possible the waste is compacted, and then most waste is grouted within containers before disposal. Wastes are currently disposed of in engineered concrete vaults on land, whereas prior to the early 1990s waste was disposed of in open clay lined trenches. Work, expected to last 4 years, has begun on the final capping of vaults, which are ready for permanent closure.

The site is owned by the NDA and operated on their behalf by NWS. In 2018, the NDA awarded the incumbent Parent Body Organisation, UK Nuclear Waste Management Limited, a third (and final) contract for the management of LLWR Limited. In January 2022, NWS was launched. This brought together the operator of the LLWR, GDF developer Radioactive Waste Management Limited and the NDA group’s integrated waste management programmes into a single organisation. A 5-year plan has been published setting out the long-term future of the site through to final closure, expected in 2129 (Low Level Waste Repository Limited 2018).

The disposal permit allows for the discharge of leachate from the site through a marine pipeline. These discharges are small compared with those discharged from the nearby Sellafield site (Appendix 1). Marine monitoring of the LLWR is therefore subsumed within the Sellafield programme, described in Section 3.3. The contribution to exposures due to LLWR discharges is negligible compared with that attributable to Sellafield and any effects of LLWR discharges in the marine environment could not, in 2024 be distinguished from those due to Sellafield.

The current permit allows for continued solid radioactive waste disposal at the site, including permission to dispose of further radioactive waste beyond Vault 8, and limits disposals against a lifetime capacity for the site. In financial year 2017/18, the site commenced its long-term Repository Development Programme (RDP) (Low Level Waste Repository Limited 2018). In 2019, Revised Joint Waste Management Plans were published for the NDA’s radioactive waste-producing site licence companies (LLWR Limited (now NWS), Magnox Limited (now NRS Limited) and Sellafield Limited), covering the financial years, 2019/20 to 2024/25. More information can be found at the UK government’s website: joint waste management plan.

Waste received at the site will have a final disposal location allocated to it at the appropriate time. Consequently, once the closure of Vault 8 has commenced as part of the RDP works, it is intended to report the quantity of solid radioactive waste finally disposed at the site. Table A1.3 records, for the financial year 2023/24, both solid radioactive wastes already disposed in Vault 8 and the solid radioactive wastes accepted by the site currently stored within Vaults 8 and 9, pending disposal. A total of 219m3 of waste was received by the site with the intention of disposal in financial year 2024/25, bringing the cumulative total to 235,000m3. The data given in Table A1.3 are recorded by financial year, instead of calendar year. All activities in terms of either disposal or receipt of solid radioactive waste with the intention of disposal have been within the lifetime capacity for the site.

Although the permit for routine disposal to the Drigg Stream has been revoked, reassurance monitoring has continued for samples of water and sediment. The results are given in Table 7.2. The tritium, gross alpha and gross beta concentrations in the stream were below the investigation levels for drinking water in the Water Supply (Water Quality) (Amendment) 2018 Regulations (retained from European Directive 2013/51). Although the stream is not known to be used as a source of drinking water, it is possible that occasional use could occur, for example by campers. If the stream was used as a drinking water supply for 3 weeks, the annual dose would be less than 0.005mSv. Concentrations of positively detected radionuclides (plutonium-238 and plutonium-239+240) in sediment from the Drigg stream were very low and similar to those in previous years. They reflect the legacy of direct discharges of leachate from the disposal site into the stream (British Nuclear Fuels Limited 2002). This practice stopped in 1991.

In the past, groundwater from some of the trenches on the LLWR site migrated eastwards towards a railway drain that runs along the perimeter of the site. Radioactivity from the LLWR was detected in the drain water. The previous operators of the site, British Nuclear Fuels plc (BNFL) took steps in the early 1990s to reduce migration of water from the trenches by building a ‘cut-off wall’ to reduce lateral migration of leachate. The results of monitoring in 2024 show that the activity concentrations have continued to be very low in the railway drain (Table 7.2) and have reduced significantly since the construction of the cut-off wall. Tritium, gross alpha and gross beta concentrations in the drain were also below the investigation levels for drinking water in the Water Supply (Water Quality) (Amendment) 2018 Regulations (retained from European Directive 2013/51).

The monitoring programme of terrestrial foodstuffs at the site was primarily directed at the potential migration of radionuclides from the waste burial site via groundwater, since the disposals of gaseous wastes are very small. Results for 2024 are given in Table 7.2 and do not indicate that radioactivity in leachate from the LLWR might be transferring to foods. Concentrations of radionuclides were generally similar to (or lower than) those measured near Sellafield (Section 3.3). The latest habits survey for the LLWR was undertaken in 2023 and the results have been included in the dose assessments for the site (Moore and others 2024b).

The ‘total dose’ from all pathways and sources of radiation was 0.20mSv in 2024, or 20% of the dose limit for members of the public of 1mSv (Table 1.2 and Table 7.1) and includes a component due to the fallout from Chernobyl and nuclear weapons testing. This dose was dominated by the effects of naturally occurring radionuclides discharged to sea from the former phosphate works at Whitehaven, with smaller contributions from legacy discharges into the sea from Sellafield and sources of direct radiation on site. If these effects were to be excluded, and only the sources of exposure from the LLWR are considered, the ‘total dose’ from gaseous releases and direct radiation was 0.029mSv in 2024 (Table 1.2). The representative person was an adult living near the site and unchanged from 2023. The decrease in ‘total dose’ (from 0.038mSv in 2023) was mostly due to a lower estimate of direct radiation. A source specific assessment of exposure for consumers of locally grown terrestrial food (animals fed on oats), using 2024 modelled activity concentrations in animal products, gives an exposure that was 0.009mSv in 2024, and similar to that in recent years.

7.2. Metals Recycling Facility, Lillyhall, Cumbria

The Metals Recycling Facility (MRF), operated by Cyclife UK Limited, is located at the Lillyhall Industrial Estate near Workington in Cumbria. The MRF predominately receives metallic waste items contaminated with low quantities of radiological contamination from clients within the UK nuclear industry and are processed in batches. Techniques used include size reduction using conventional hot and cold cutting methods, with subsequent decontamination using industrial grit blasting equipment.

The permit for the MRF site allows discharges of low gaseous waste to the environment via a main stack and of aqueous waste to the sewer, all discharges in 2024 were within permitted limits (Appendix 1, Table A1.1 and Table A1.2). As in recent years, direct radiation from the site was less than 0.001mSv in 2024 (Table 1.1) and the radiological impact was low.

A habits survey, focusing on direct radiation pathways was undertaken in 2018 (Clyne 2021). This was the first habits survey to be carried out at the MRF, and it was undertaken to ensure consistency with other nuclear sites in the UK. The qualitative survey focussed on the area adjacent to the waste container park that had resulted in the elevated dose rates in 2016. Quantitative habits data were not obtained as the time spent by members of the public undertaking activities in the area was minimal.

7.3 Tradebe-Inutec, Winfrith, Dorset

The Tradebe-Inutec site is a radiological waste processing facility, for the wider nuclear industry, located adjacent to the NRS Winfrith site. In early 2019, Tradebe-Inutec acquired buildings and land at Winfrith from the NDA and the ONR and Environment Agency granted a new nuclear site licence and environmental permit transfer (respectively) to Inutec Limited, who trade as Tradebe-Inutec. Prior to this, Tradebe-Inutec had been operating as a tenant of Magnox Limited, now NRS. The impact of its site operations and gaseous discharges is considered along with those from the NRS Winfrith site (in Section 5.4).

Gaseous discharges from Tradebe-Inutec are also made via stacks to the local environment and are given in Appendix 1 (Table A1.1). As in recent years, discharges of alpha, carbon-14 and other radioelements were less than 1% of the discharge limits. The dose from direct radiation from the Tradebe-Inutec site was lower (<0.001mSv) than the NRS Winfrith site (Table 1.1).

Liquid waste from Tradebe-Inutec is transferred off site for disposal into Southampton Water under a non-nuclear permit (included in Table 7.9) and therefore, these impacts are not considered in the RIFE report.

7.4. Other solid waste disposal sites

Some organisations are granted permits by SEPA (in Scotland), the Environment Agency (in England) and NRW (in Wales) to dispose of solid wastes containing low quantities of radioactivity to approved landfill sites. In Northern Ireland, this type of waste is transferred to Great Britain for incineration. Waste with very low quantities of radioactivity can also be disposed of in general refuse.

The UK government introduced a more flexible framework in 2024 for the disposal of certain categories of LLW to landfill. Further details and information are provided on the website: UK policy framework for managing radioactive substances and nuclear decommissioning.

In England and Wales, disposal of LLW at landfill sites requires both landfill companies and nuclear operators to hold permits to dispose of LLW and very low-level waste (VLLW). The 2007 government policy led to applications from landfill operators for permits to dispose of LLW at their sites. The landfill sites were:

  • Waste Recycling Group Limited (part of FCC Environmental) at the Lillyhall Landfill Site in Cumbria. Their revised permit, issued in 2021, allows disposal of VLLW.
  • Augean at the East Northants Resource Management Facility (ENRMF), near Kings Cliffe, Northamptonshire. Their permit, issued in 2016, allows the disposal of low activity LLW and VLLW. The Environment Agency undertook a baseline survey as described in previous RIFE reports (for example [64])
  • Suez Recycling and Recovery UK Limited (formerly SITA UK) at Clifton Marsh in Lancashire. A permit to dispose of LLW was issued by the Environment Agency in 2012.

Radioactivity in wastes can migrate into leachate and in some cases can enter the groundwater. SEPA and the Environment Agency carry out monitoring of leachates and off-site watercourses. The locations of landfill sites considered in 2024 are shown in Figure 7.1 and the results are presented in Table 7.3 and Table 7.4, alongside the respective regions and locations.

Figure 7.1. Solid waste disposal sites monitored in 2024.

The results, in common with previous years, showed evidence for migration of tritium from some of the disposal sites. The reported tritium concentrations vary from year to year. The variation is thought to be related to changes in rainfall quantity and resulting leachate production and the use of different boreholes for sampling. A possible source of the tritium is thought to be due to disposal of Gaseous Tritium Light Devices (Mobbs, Barraclough & Napier 1998). As in recent years, inadvertent ingestion of leachate (2.5 litres per year) from the Cathkin landfill (City of Glasgow) site (with the highest observed concentration of tritium) would result in a dose of less than 0.005mSv in 2024 (Table 7.1), or less than 0.5% of the dose limit for members of the public of 1mSv. Similarly, the annual doses from ingestion of uranium isotopes in leachate from Clifton Marsh and inadvertent ingestion of borehole or surface water close to the ENRMF were also less than 0.005mSv in 2024. The latter assessment excludes potassium-40 because its presence is homeostatically controlled in the body.

Gross beta concentrations in off-site watercourses were below the investigation levels for drinking water in the Water Supply (Water Quality) (Amendment) 2018 Regulations (retained from the European Directive 2013/51) of and 1.0Bq l-1, respectively. The gross alpha concentration at Distington Beck was above the 0.1Bq l-1 investigation level, however, this is unlikely to be used as a source of drinking water.

The results, in common with previous years, showed evidence for migration of tritium from some of the disposal sites. The reported tritium concentrations vary from year to year. The variation is thought to be related to changes in rainfall quantity and resulting leachate production and the use of different boreholes for sampling. A possible source of the tritium is thought to be due to disposal of Gaseous Tritium Light Devices (Mobbs and others 1998). As in recent years, inadvertent ingestion of leachate (2.5litres per year) from the Cathkin landfill (City of Glasgow) site (with the highest observed concentration of tritium) would result in a dose of less than 0.005mSv in 2024 (Table 7.1), or less than 0.5% of the dose limit. Similarly, the annual dose from ingestion of uranium isotopes in leachate from Clifton Marsh was also less than 0.005mSv in 2024.

SEPA’s monitoring programme at the Stoneyhill Landfill Site in Aberdeenshire, authorised to dispose of conditioned NORM waste, ceased in 2016. Results up to 2015 are included in earlier RIFE reports and show no significant radiological impact (for example (Environment Agency, Food Standards Agency, Scotland and others 2016)).

NORM is found within oil and gas reserves and is consequently extracted along with the oil and gas. The NORM can precipitate onto oil and gas industry equipment creating an insoluble scale (NORM scale). The presence of this scale reduces the efficiency of the equipment and must be removed. Suez Recycling and Recovery UK Limited, the operators of the Stoneyhill Landfill site, has constructed a descaling facility adjacent to the landfill in partnership with Nuvia Limited. This facility descales oil and gas industry equipment, such as pipes, using pressurised water. The solid scale removed from the equipment is then grouted into drums and can be consigned to Stoneyhill Landfill site in accordance with the authorisation granted in 2012.

7.5. Former phosphate processing plant, Whitehaven, Cumbria

An important historical anthropogenic source of naturally occurring radionuclides in the marine environment was the former phosphate processing plant near Whitehaven in Cumbria, which used to manufacture phosphoric acid (for use in detergents) from imported phosphate ore (Rollo and others 1992). Processing of ore resulted in a liquid waste slurry (phosphogypsum) containing most of the thorium, uranium and radioactive decay products (including polonium-210 and lead-210) originally present in the ore, and this was discharged by pipeline to Saltom Bay.

The slurry is regarded as NORM from industrial activity. Historical discharges continue to have an impact, through the production of the radioactive products. The impact is due to the decay of long-lived parent radionuclides previously discharged to sea. Both polonium-210 and lead-210 are important radionuclides in that small changes in activity concentrations above background significantly influence the dose contribution from these radionuclides. This is due to their relatively high dose coefficient used to convert intake of radioactivity into a radiation dose.

Processing of phosphoric acid at the plant ceased at the end of 2001. The plant was subsequently decommissioned and the authorisation to discharge radioactive wastes was revoked by the Environment Agency.

The results of routine monitoring for naturally occurring radioactivity near the site in 2024 are shown in Table 7.5. Routine analytical effort is focused on polonium-210 and lead-210, which concentrate in marine species and are the important radionuclides in terms of potential dose to the public. As in previous years, polonium-210 and other naturally occurring radionuclides were slightly enhanced near Whitehaven but reduced to background values further away. Figure 7.2 to Figure 7.4 show how concentrations of polonium-210 in winkles, crabs and lobsters have generally decreased since 1998, with larger concentrations variations in lobsters since 2014. Concentrations in the early 1990s were more than 100Bq kg-1 (fresh weight), when discharges were taking place, prior to a change in site operations (in 1992) and later plant closure in 1997. There were some small variations in concentrations of polonium-210 in local samples in 2024 (where comparisons can be made), in comparison with those in 2023. Polonium-210 concentrations were generally lower in both crab and lobster samples in 2024, and as in recent years, these concentrations continued to be within or close to the expected range due to natural sources. For crustacean and other seafood samples, it is now difficult to distinguish between the measured radionuclide concentrations and the range of concentrations normally expected from naturally sourced radioactivity. The latter are shown in Figure 7.2 to Figure 7.4 and in Appendix 6 (observed minimum, median and maximum concentrations of polonium-210 in each species, as reported in Young, McCubbin & Camplin (2002) and Young and others (2003)). There were small enhancements for some samples at other locations above the expected natural background median values for marine species, however, the majority were within the ranges observed in the undisturbed marine environment. It is considered prudent to continue to estimate doses at Whitehaven whilst there remains an indication that concentrations are higher than natural background. Further analysis has confirmed that this approach is unlikely to underestimate doses (Dewar and others 2014).

Figure 7.2. Polonium-210 concentration, in Bq kg-1 (fresh), in winkles at Parton, 1995 to 2024.

Figure 7.3. Polonium-210 concentration, in Bq kg-1 (fresh), in crabs at Parton, 1995 to 2024.

Figure 7.4. Polonium-210 concentration, in Bq kg-1 (fresh), in lobsters at Parton, 1995 to 2024.

In 2018, the Environment Agency, with the support of the FSA, NIEA and SEPA, performed additional polonium-210 analyses in shellfish samples to obtain baseline data, providing naturally sourced polonium-210 concentrations that are unlikely to be influenced by NORM in the Irish Sea. Further details are presented in RIFE 24 (Environment Agency, Food Standards Agency, Food Standards Scotland, Natural Resources Wales and others 2019).

The exposure pathway considered for the assessment at Whitehaven was internal irradiation, due to the ingestion of naturally occurring radioactivity in local fish and shellfish. The representative person was a Cumbrian coastal community consumer who, centred on the Sellafield site to the south of Whitehaven, obtained their sources of seafood from locations such as Whitehaven, Nethertown and Parton. This consumer is also considered in the assessment of the marine impacts of the Sellafield and LLWR sites (Sections 3.3 and 7.1). The estimated contribution due to background median concentrations of naturally occurring radionuclides is subtracted from the measured activity concentration. Consumption rates for people who eat seafood at high rates were reviewed and revised in 2024 (Moore and others 2024a). Revised figures for consumption rates, together with occupancy rates, are provided in Appendix 4 (Table A4.2). The dose coefficient for polonium-210 is based on a value of the gut transfer factor of 0.5 for all foods.

The ‘total dose’ to a local high-rate consumer of seafood was 0.20mSv in 2024 (Table 7.1), or 20% of the dose limit to members of the public. This is a decrease from 0.23mSv in 2023. The dose includes the effects of all sources near the site: as explained in Section 3. The contribution to the ‘total dose’ from enhanced natural radionuclides was 0.18mSv and was lower in 2024, compared to that in 2023 (0.21mSv). The decrease in ‘total dose’ in 2024 was mostly attributed to lower concentrations of polonium-210 in crab and lobsters. The largest contribution to dose to a Cumbrian coastal community seafood consumer near Whitehaven and Sellafield continues to be from historical discharges near Whitehaven. A source specific dose assessment targeted directly at local consumers of seafood (at high rates), gives an exposure of 0.31mSv in 2024 (Table 7.1).

The longer-term trend in annual ‘total dose’ over the period 2013 to 2025 is shown in Figure 7.5. The variations in ‘total dose’ over the period 2013 to 2024 reflect changes in polonium-210 concentrations, consumption rates and the range of seafood species consumed by individuals at high-rates, including that of crustaceans. Over a longer period, the trend is of generally declining dose (Environment Agency, Food Standards Agency, Food Standards Scotland, Natural Resources Wales and others 2018).

Figure 7.5. Trend in ‘total dose’, in mSv y-1, to seafood consumers from naturally-occurring radionuclides near Whitehaven, 2013 to 2024.

Year Dose, mSv y-1
2013 0.021
2014 0.15
2015 0.35
2016 0.34
2017 0.18
2018 0.33
2019 0.20
2020 0.25
2021 0.19
2022 0.22
2023 0.21
2024 0.18

7.6. Holy Loch, Argyll and Bute

A small programme of monitoring at Holy Loch continued during 2024 to determine the effects of past discharges from the US submarine support facilities which closed in 1992. Radionuclide concentrations in the sediment sample collected in 2024 were low (Table 7.11(a)). Gamma dose rate measurements over intertidal areas (Table 7.11(b)) were similar to those values reported in recent years. As reported in RIFE 29 (Environment Agency and others 2024), no dose assessment was undertaken for the site as there are no radioactive discharges to the loch and monitoring provides confidence that there is no realistic risk to the public using the area.

Should results indicate that a dose assessment is needed, this will be undertaken.

7.7. Former military airbase, Dalgety Bay, Fife

Radioactive items containing radium-226 and associated decay products have been detected at Dalgety Bay in Fife since at least 1990. The contamination is associated with historical disposals of waste from past military operations at the Royal Naval Air Station (RNAS) Donibristle, which closed in 1959 and upon which large areas of the town of Dalgety Bay have been built. The air station played a role as an aircraft repair, refitting and salvage yard. It is believed that waste was incinerated, and the resultant ash and clinker was disposed of by reclaiming land from the sea. Following years of erosion at the site the contamination is being exposed on and adjacent to the foreshore. Some of the incinerated material contained items such as dials and levers which had been painted with luminous paint containing radium-226.

In 1990, environmental monitoring showed elevated activity concentrations in the Dalgety Bay area. The monitoring was undertaken as part of the routine environmental monitoring programme for Rosyth Royal Dockyard Limited conducted in accordance with the dockyard’s authorisation to dispose of liquid radioactive effluent to the Firth of Forth. Some material was removed for analysis, which indicated the presence of radium-226. Further investigation confirmed that the contamination could not have originated from the dockyard and was most likely to be associated with past practices related to the nearby former RNAS Donibristle or HMS Merlin military airfield. Since this initial discovery, there have been several monitoring exercises to determine the extent of this contamination. In 2017, SEPA issued guidance on monitoring for heterogeneous radium-226 sources resulting from historic luminising activities or waste disposal sites (Scottish Environment Protection Agency 2017).

Additional public protection measures were established following the increased number of particles and the discovery of some high activity particles in 2011. These were maintained between 2024 and 2025. A monthly beach monitoring and particle recovery programme was adopted in 2012 by a contractor working on behalf of the MOD and this remains in place. The information signs advising the public of the contamination and precautions to be taken remain in place. In addition, the FEPA Order issued by FSS (then FSA in Scotland) prohibiting the collection of seafood from the Dalgety Bay area remains in force. SEPA undertook a one-year programme of shellfish monitoring from February 2012 during which no particles were detected in the shellfish. All shellfish samples collected were analysed for the presence of radium-226 and all were reported as less than values. During routine monitoring of mussel beds in 2015 a particle was detected in this area (for the first time since 2011) and retrieved, indicating that the continuation of these protection measures is reducing the risks to members of the public whilst further work continues to address the contamination.

The Committee on Medical Aspects of Radiation in the Environment (COMARE) recommended that effective remediation of the affected area be undertaken as soon as is possible. This recommendation followed the publication of the risk assessment in 2013, which was considered alongside the Appropriate Person Report. This Appropriate Person Report included a comprehensive study of the land ownership and history at Dalgety Bay. The COMARE recommendation, amongst others, was subsequently published in 2014 in COMARE’s 15th report. The MOD has progressed with addressing the contamination by initially publishing its Outline Management Options Appraisal Report in 2014, followed by a further publication in 2014 of its broad management strategy and timescale for implementation of its preferred management option. Copies of these reports are available on the UK government website: committee on medical aspects of radiation in the environment.

The environmental impact assessment (EIA) in support of the planning application for the remediation works was submitted to Fife Council for consideration. In 2017, the planning application for the remediation works was submitted to Fife Council and subsequently approved.

The remediation contract was awarded by MOD in February 2020 and an EASR18 permit to undertake the required work was granted by SEPA in May 2021. Remediation work took place between 2021 and 2023. The works involved extraction of beach material which was then transferred to a compound where the material was screened for asbestos and then radioactive contamination on a conveyor system.

Asbestos material and oversized material were monitored for radioactive contamination separately by hand.

Screened material was then replaced onto the beach. This was covered with a geotextile membrane on top of which graded rock armour was fixed in place.

It is estimated that a total of over 13,000 items have been removed from the beach as a result of both the remediation works and previous monitoring undertaken since 1990.

Verification monitoring will be undertaken following completion of the works for at least 2 years. By analysing the activity range and depth of particles recovered from the area, SEPA will determine if the remediation objective has been met. Following this the site will then be regularly monitored by SEPA (radiological monitoring) and Fife Council (rock armour assessment).

Further details on the work at Dalgety Bay can be found on the Radioactive Substances pages on SEPA’s website: SEPA Dalgety Bay.

7.8. Former military airbase, Kinloss Barracks, Moray

Radioactive items containing radium-226 and associated decay products have been detected on an area of land which used to form part of the former RAF Kinloss, now Kinloss Barracks. The contamination is associated with historical disposals of waste from past military operations at the site resulting from the dismantling of aircraft no longer required by the RAF following World War II. During the late 1940s, the aircraft were stripped for their scrap metal, with the remains being burnt and/or buried at the site. The source of the radium-226 and associated decay products are the various pieces of aircraft instrumentation which were luminised with radium paint.

SEPA has undertaken monitoring surveys at the site which positively identified the presence of radium-226 and has published an assessment of the risks posed to the public (Natural Scotland & Scottish Environment Protection Agency 2016). Currently, the site is largely undeveloped open land covered in gorse, with several wind turbines and access tracks. The area has a few informal paths crossing the land that is used by visitors and dog walkers. The contamination detected at the site is all currently buried at depth. Current uses of the site do not involve intrusion into the ground to any significant depth; thus, there is no current pathway for exposure via skin contact, ingestion or inhalation. Exposure via external gamma irradiation is possible but is significantly below the relevant dose criteria detailed in the Radioactive Contaminated Land Statutory Guidance (Scottish Executive 2006; Scottish Government 2009).

The risk assessment of the series of monitoring surveys concluded that, under its current use, there are no viable or credible exposure pathways for the public to be exposed to the contamination and that this site does not currently meet the definition of radioactive contaminated land (Natural Scotland & Scottish Environment Protection Agency 2016). However, SEPA will keep this site under review as a change in land use on the site may alter the potential exposure pathways. To access the full risk assessment report please visit the radioactive substances pages available on SEPA’s website: www.sepa.org.uk.

7.9. Other non-nuclear sites

Small quantities of gaseous and liquid radioactive wastes are routinely discharged from a wide range of other non-nuclear sites in the UK on land (including to the atmosphere from industrial stacks and incinerators), and from offshore oil and gas installations.

A summary of the most recent data for the quantities discharged under regulation for England and Northern Ireland in 2024 is given in Table 7.6 and Table 7.7. Data for Scotland are presented in Table 7.8 and Table 7.9 in terms of OSPAR regions (Region II represents the Greater North Sea and Region III the Celtic Sea). Data for Wales are presented in Table 7.10. This change in format allows easier trend analysis to be performed for OSPAR. The data are grouped according to the main industries giving rise to such wastes in the UK and exclude information for other industries considered in other sections of this report, principally the nuclear sector. The main industries are:

  • oil and gas, both off and onshore
  • education, including universities and colleges
  • hospitals
  • other, which includes research, manufacturing and public sector

Discharges may also occur without an authorisation or permit when the quantities are below the need for specific regulatory control. For example, discharges of natural radionuclides are made from coal-fired power stations because of the presence of trace quantities of uranium and thorium and their decay products in coal (Corbett 1983).

As indicated in Section 1, general monitoring of the British Isles as reported elsewhere in this report has not detected any gross effects from non-nuclear sources. Occasionally, routine programmes directed at nuclear site operations detect the effects of discharges from the non-nuclear sector and, when this occurs, a comment is made in the relevant nuclear site text. The radiological impact of the radioactivity from the non-nuclear sector detected inadvertently in this way is very low.

Monitoring of the effect of the non-nuclear sector is limited because of the relatively low impact of the discharges. However, programmes are carried out to confirm that impacts are low and, when these occur, they are described in this report.

The Pharmaron UK radiolabelling facility in Cardiff, discharges tritium and carbon-14 to the atmosphere and to the marine environment, via the Cardiff sewage treatment works outfall. This site began operation after Quotient Bioresearch (Radiochemicals) Ltd in 2010 (later becoming Pharmaron UK in 2017) acquired GE Healthcare’s custom radiolabelling division which previously operated at the Maynard Centre in Cardiff (previously reported in RIFE (Environment Agency, Food Standards Agency and others 2012)). These operations were then moved to new premises in Cardiff, under a non-nuclear permit with lower discharge limits. Discharges from the Pharmaron UK facility are included in the discharges reported in Table 7.11. The radiological impacts of these discharges are low.

In 2024, SEPA continued to undertake a small-scale survey (as part of the annual programme) of the effects of discharges from non-nuclear operators by analysing mussel samples and other materials from the River Clyde, the Firth of Forth and sludge pellets from a sewage treatment works (at Daldowie). The results are given in Table 7.12. The results in 2024 were generally similar to those in 2023. Activity concentrations were typical of the expected effects from Sellafield discharges at this distance and the presence of iodine-131 in sludge pellets (probably from a hospital source). An assessment was undertaken to determine the dose to the representative high-rate mollusc consumer. The dose was estimated to be less than 0.005mSv in 2024, or approximately 0.5% of the dose limit for members of the public, and unchanged from 2023.

Scotoil, in Aberdeen City, operates a cleaning facility for equipment from the oil and gas industry contaminated with enhanced concentrations of radionuclides of natural origin. The facility is authorised to discharge liquid effluent to the marine environment within the limitations and conditions of the authorisation, which includes limits for radium-226, radium-228, lead-210 and polonium-210 discharges. The authorisation includes conditions requiring Scotoil to undertake environmental monitoring. Prior to their operations, a fertiliser manufacturing process was operated on the site and made discharges to sea. Monitoring of seaweed (‘Fucus vesiculosus’) from Nigg Bay, near Aberdeen Harbour was carried out in 2024 and are reported in Table 3.11. In 2024, the dose rate on sediment was 0.074µGy h-1 and similar to background.

8. Regional monitoring

Highlights

  • Doses for the representative person were approximately 1% (or less) of the annual public dose limit in 2024

Regional monitoring in areas remote from nuclear sites continued in 2024:

  • to establish long distance transport of radioactivity from UK and overseas nuclear sites
  • to indicate general contamination of the food supply and the environment
  • to provide data under UK obligations under the OSPAR Convention

The routine component parts of this programme are: sampling of seafood and environmental samples from the Channel Islands and Northern Ireland; monitoring UK ports of entry for foodstuffs for other non-specific contamination; sampling of the UK food supply, air, rain, sediments, drinking water and seawater. Data tables, in Open Document Spreadsheet (ODS) format, are downloadable from the main RIFE page.

8.1. Channel Islands

Samples of marine environmental materials were provided by the Channel Island States and analysed for a range of radionuclides. The programme monitors the effects of radioactive discharges from the French reprocessing plant at La Hague and the power station at Flamanville. It also monitors any effects of historical disposals of radioactive waste in the Hurd Deep, a natural trough in the western English Channel. Fish and shellfish are monitored to determine exposure from the internal radiation pathway, and sediment is analysed for external exposures. Seawater and seaweeds are sampled as environmental indicator materials, and, in the latter case, because of their use as fertilisers. A review of marine radioactivity in the Channel Islands from 1990 to 2009 has been published (Hughes, Runacres & Leonard 2011).

The results of monitoring for 2024 are given in Table 8.1; as in 2023, no samples were collected or analysed from Alderney. There was evidence of routine releases from the nuclear industry in some food and environmental samples (for example, technetium-99). However, activity concentrations in shellfish were low and similar to those in previous years. It is generally difficult to attribute the results to different sources, including fallout from nuclear weapons testing, due to the low values detected. No evidence for significant releases of activity from the Hurd Deep site was found.

In 2024, the dose to the representative person, consuming large amounts of fish and shellfish was estimated to be less than 0.005mSv, or less than 0.5% of the dose limit for members of the public. The assessment included a contribution from external exposure. The concentrations of artificial radionuclides in the marine environment of the Channel Islands and the effects of discharges from local sources, therefore, continued to be of negligible radiological significance.

The collection of milk and crop samples from the Channel Island States ceased in 2014. Results up to 2013 are included in earlier RIFE reports (for example Environment Agency and others 2013) and the data indicated no significant effects from UK or other nuclear installations.

8.2. Isle of Man

Following review of their monitoring programmes, the FSA’s terrestrial and aquatic monitoring and the Environment Agency’s marine monitoring on the Isle of Man ceased in 2013 and 2016, respectively, see References (Environment Agency, Food Standards Agency, Natural Resources Wales and others 2014; Environment Agency and others 2015; Environment Agency, Food Standards Agency, Food Standards Scotland and others 2016; Environment Agency and others 2017) for more details. Results up to 2015 are included in earlier RIFE reports (for example (Environment Agency, Food Standards Agency, Scotland and others 2016)). Previous results have demonstrated that there has been no significant impact on the Isle of Man from discharges to sea from mainland nuclear installations in recent years.

The Government of the Isle of Man undertakes their own independent radioactivity monitoring programme and provides an indication of the far-field effects of current and historical discharges from Sellafield and other UK nuclear sites. These are reported annually: Isle of Man environmental radioactivity

8.3. Northern Ireland

The NIEA monitors the far-field effects of liquid discharges from Sellafield into the Irish Sea. The programme involved sampling fish, shellfish, and indicator materials from a range of locations along the coastline (Figure 8.1). The sample species, type and locations are listed in the respective site tables. Gamma dose rates were measured over intertidal areas to assess the external exposure pathway. The results of monitoring are given in Table 8.2(a) and Table 8.2(b).

Figure 8.1. Monitoring locations in Northern Ireland, 2024.

In 2024, the main effect of discharges from Sellafield was observed in concentrations of technetium-99 in shellfish and seaweed samples. These were similar to values reported in recent years, reflecting the considerably decreased inputs to the Irish Sea (see also Section 3.3.3). Caesium-137 concentrations were low and generally similar to those in 2023 and over the period 2003 to 2024. As expected, low concentrations of transuranic radionuclides were also detected in 2024. Reported concentrations are less than those found nearer to Sellafield and continued to be low, as in recent years (Figure 8.2). Further information on the trends in radioactivity in the marine environment of Northern Ireland has been published (Ly and others 2015). The gamma dose rates over intertidal areas were similar to those in previous years.

Figure 8.2(a). Concentrations of americium-241 and caesium-137, in Bq kg-1 (dry), in coastal sediments at Portrush, 2002 to 2024.

Figure 8.2(b). Concentrations of americium-241 and caesium-137, in Bq kg-1 (dry), in coastal sediments at Ballymacormick, 2002 to 2024.

Figure 8.2(c). Concentrations of americium-241 and caesium-137, in Bq kg-1 (dry), in coastal sediments at Carlingford Lough, 2002 to 2024.

A survey of consumption and occupancy in coastal regions of Northern Ireland established the habits of people consuming large quantities of fish and shellfish (Smith and others 2002). Based on the monitoring results from the marine environment in 2024, the annual dose from the consumption of seafood and exposure over intertidal areas was 0.007mSv (Table 3.15), or less than 1% of the dose limit for members of the public.

Monitoring results for the terrestrial environment of Northern Ireland are included in the following parts of Section 8.

8.4. General diet

As part of the UK government and devolved administrations’ general responsibility for food safety, concentrations of radioactivity are determined in regional diets. These data (and data on other dietary components in Sections 8.5 and 8.6) previously formed the basis of the UK submission to the European Commission. While these data are no longer supplied to the European Commission for England, Wales and Northern Ireland, they will continue to be published in the RIFE reports.

In 2024, the concentrations found in a survey of radioactivity in canteen meals collected across the UK, and mixed diets in Scotland, were very low or typical of natural sources (Table 8.3). Activity concentrations were generally similar to those in previous years.

8.5. Milk

The programme of milk sampling across dairies in the UK continued in 2024. The aim is to collect monthly milk samples and analyse them for their radionuclide content. This programme provides useful information with which to compare data from farms close to nuclear sites and other establishments that may enhance values above background activity concentrations.

The results of milk monitoring for 2024 are summarised in Table 8.4. Most results were similar to those in previous years (where comparisons can be made). The mean carbon-14 concentrations in England, Northern Ireland, Wales, and Scotland were all close to the expected background concentration in milk (see Appendix 6). The maximum concentrations of carbon-14 in milk for England (North Yorkshire), Northern Ireland (Co. Tyrone), Wales (Clywd), and Scotland (Renfrewshire) were 24Bq l-1 , 22Bq l-1 , 18Bq l-1 and less than 16Bq l-1 , respectively. As in previous years, tritium concentrations were reported as less than values at all remote sites. In 2024, strontium-90 concentrations were reported as less than values (or just above the less than value), and the mean concentration over the UK was less than 0.034Bq l-1 (compared to 0.033Bq l-1 in 2023). In the past, the highest concentrations of radiocaesium in milk were from those regions that received the greatest amounts of fallout from Chernobyl. However, the concentrations are now very low, and it is not possible to distinguish this trend.

The radiation dose from consuming milk at average rates was assessed for various age groups. In 2024, the most exposed age group was infants (1-year-old). For the range of radionuclides analysed, the annual dose was less than 0.005mSv or less than 0.5% of the dose limit. Previous surveys (for example, Food Standards Agency & Scottish Environment Protection Agency 2002) have shown that if a full range of nuclides were to be analysed and assessed, the dose would be dominated by naturally occurring lead-210 and polonium-210, and artificial radionuclides would contribute less than 10% of the dose.

8.6 Crops

The programme of monitoring naturally occurring and artificial radionuclides in crops (in England, Wales and the Channel Islands) as a check on general food contamination (remote from nuclear sites) ceased in 2014. Further information on previously reported monitoring is available in earlier RIFE reports (for example (Environment Agency, Food Standards Agency, Natural Resources Wales and others 2014)).

8.7. Airborne particulate, rain, freshwater and groundwater

Radioactivity in rainwater and air was monitored at several UK locations as part of the programme of background sampling managed by the Environment Agency and SEPA. These data are collected on behalf of the DESNZ, NIEA and, the Scottish and Welsh Governments. The results of monitoring are given in Table 8.5. The routine programme is comprised of 2 components:

  • regular sampling and analysis on a quarterly basis
  • supplementary analysis on an ‘ad hoc’ basis

Tritium and caesium-137 concentrations in air and rainwater are reported as less than values in 2024. Caesium-137 concentrations in air, as in recent years, remain less than 0.01% of those observed in 1986, the year of the Chernobyl reactor accident.

Concentrations of beryllium-7, a naturally occurring radionuclide formed by cosmic ray reactions in the upper atmosphere, were positively detected at similar values at all sampling locations. Peak air concentrations of this radionuclide tend to occur during spring and early summer, as a result of seasonal variations in the mixing of stratospheric and tropospheric air (Environment Agency 2002). Activity concentrations of the radionuclides reported in air and rainwater were very low and do not currently merit radiological assessment.

Sampling and analysis of freshwater from drinking water sources throughout the UK continued in 2024 (Figure 8.3). The sample locations and regions are listed in the respective site tables. These water data are collected by the Environment Agency (for England and Wales), NIEA (for Northern Ireland) and SEPA (for Scotland). Sampling was designed to represent the main drinking water sources, namely reservoirs, rivers and groundwater boreholes. Most of the water samples were representative of natural waters before treatment and supply to the public water system.

Figure 8.3. Sources of drinking water sampling locations, 2024.

The results are given in Table 8.6 to Table 8.8 (inclusive). Tritium concentrations were all substantially below the investigation level for drinking water of 100Bq l-1 in the Water Supply (Water Quality) (Amendment) 2018 Regulations (retained from European Directive 2013/51) (where applicable) and all are reported as less than values except for one result). At Gullielands Burn (Table 8.6), which is near to the Chapelcross nuclear site, the tritium concentration was 12Bq l-1 in 2024 (similar to that in recent years).

The mean annual dose from consuming drinking water in the UK was 0.012mSv in 2024 (Table 8.9), which is unchanged from the mean annual dose in 2023. The highest annual dose was estimated to be 0.016mSv for drinking water from Matlock, Derbyshire. The estimated doses were dominated by naturally occurring radionuclides and are generally similar to those reported in previous years. The annual dose from artificial radionuclides in drinking water was less than 0.001mSv.

Collection and analysis of groundwater samples from across Scotland was not performed in 2024. It is expected that collection and analysis of these samples will resume in 2026 and thereafter. Results up to 2019 are included in earlier RIFE reports (for example, (Environment Agency and others 2020)).

8.8. Overseas incidents

Two overseas accidents have had direct implications for the UK: Chernobyl (1986) and Fukushima Dai-ichi (2011). Earlier RIFE reports have provided detailed results of monitoring by the environment agencies and the FSA (Environment Agency, Food Standards Agency and others 2012).

For Chernobyl, the main sustained impact on the UK environment was in upland areas, where heavy rain fell in the days following the accident, but activity concentrations have now reduced substantially. The results of monitoring and estimated doses to consumers are available in earlier RIFE reports.

During 2025 SEPA has received a number of enquiries from the public in relation to windfarm construction activities and the potential impact of release of Chernobyl contamination. A dose assessment has been prepared and is available on SEPA’s website: Radioactivity and Wind Farm Developments on peatlands. SEPA calculated that windfarm construction activities did not pose a realistic risk to public health. Samples of peat will be collected and analysed during 2025, and the results will be made available in RIFE 31.

The accident at the Fukushima Dai-ichi nuclear power station in Japan in March 2011 resulted in significant quantities of radioactivity being released into the air and sea. Controls on imported food and animal feed products from Japan were implemented in 2011 (revised in 2016 and 2019). These controls were revoked in June 2022 for Great Britain (England, Wales and Scotland).

In Northern Ireland, European Regulations continue to apply under the terms of the UK’s withdrawal agreement from the EU. In September 2021, the EU published Commission Implementing Regulation (EU) 2021/1533 (European Commission 2022), which were in force, until July 2023 when these regulations were repealed by the EU (under 2023/1453).

A full description of the legislation, requirements and procedures involved for imports are provided in earlier RIFE reports (Environment Agency, Food Standards Agency and others 2021).

Screening instruments are used at importation points of entry to the UK as a general check on possible contamination from unknown sources. One example of how these screening instruments can be triggered occurred at Dover, when the presence of caesium-137 was detected in a consignment of food being brought into the UK. A sample of dried blueberry powder was analysed, and the activity concentration was 396Bq kg-1 . At this concentration, the FSA considered that there was no food safety requirement to limit their placement on the market for human consumption.

8.9. Seawater surveys

The UK government and devolved administrations are committed to preventing pollution of the marine environment from ionising radiation, with the main aim of reducing concentrations in the environment to near background values for naturally occurring radioactive substances, and close to zero for artificial radioactive substances (Department for Business Energy and Industrial Strategy 2018). Therefore, a programme of surveillance into the distribution of important radionuclides is maintained using research vessels and other means of sampling.

The seawater surveys reported here also support international studies concerned with the quality status of coastal seas. The programme of radiological surveillance work provided the source data and, therefore, the means to monitor and assess progress in line with the UK’s commitments towards OSPAR’s 1998 Strategy for Radioactive Substances target for 2020 (part of the North-East Atlantic Environment Strategy adopted by OSPAR for the period 2010 to 2020), see Section 1.3.2 of this report for more details. The surveys also provide information that can be used to distinguish different sources of artificial radioactivity (for example, (Kershaw & Baxter 1995)) and to derive dispersion factors for nuclear sites (for example, (Baxter & Camplin 1994)). In addition, the distribution of radioactivity in seawater around the British Isles is a significant factor in determining the variation in individual exposures at coastal sites, as seafood is a major contribution to food chain doses.

The research vessel programme on radionuclide distribution currently comprises annual surveys of the Bristol Channel, western English Channel and biennial surveys of the Irish Sea and the North Sea. The results obtained in 2024 are given in Figure 8.4 to Figure 8.8 and are discussed in the text below.

Figure 8.4. Concentrations (Bq l-1) of caesium-137 in surface water from the North Sea, August 2024.

Figure 8.5. Concentrations (Bq l-1) of caesium-137 in surface water from the English Channel, March 2024.

Figure 8.6. Concentrations (Bq l-1) of tritium in surface water from the North Sea, August 2024.

Figure 8.7. Concentrations (Bq l-1) of tritium in surface water from the Bristol Channel, September 2024.

Figure 8.8. Concentrations (Bq l-1) of tritium in surface water from the English Channel, March 2024.

A seawater survey of the North Sea was carried out in 2024. Caesium-137 concentrations are given in Figure 8.4 and show that concentrations were very low (up to 0.014Bq l-1 ) throughout the survey area. The few positively detected values were only slightly above those observed for global fallout levels in surface seawaters (0.0001 to 0.0028Bq l-1, (Povinec and others 2005)). The overall distribution in the North Sea is characteristic of that observed in previous surveys over the last decade, with generally positively detected values near the coast, due to the long-distance transfer, possibly from Sellafield- or Chernobyl-derived activity. In 2024, there was no significant evidence of input of Chernobyl-derived caesium-137 from the Baltic (via the Skaggerak) close to the Norwegian Coast. Recently, trends and observations of caesium-137 concentrations in the waters of the North Sea (and Irish Sea), over the period 1995 to 2015, have been published (Leonard and others 2017).

Over several decades, the impact of discharges from the reprocessing plants at Sellafield and La Hague has been readily apparent, carried by the prevailing residual currents from the Irish Sea and the Channel, respectively (Povinec and others 2003). Caesium-137 concentrations in the North Sea have tended to follow the temporal trends of the discharges, albeit with a time lag. The maximum discharge of caesium-137 occurred at Sellafield in 1975, with concentrations of caesium-137 of up to 0.5Bq l-1 in the North Sea surface waters in the late 1970s. Due to significantly decreasing discharges after 1978, remobilisation of caesium-137 from contaminated sediments in the Irish Sea was considered to be the dominant source of water contamination for most of the North Sea (McCubbin and others 2002).

Current caesium-137 concentrations in the Irish Sea are only a very small percentage of those prevailing in the late 1970s (typically up to 30Bq l-1 , (Baxter, Camplin & AK 1992)), when discharges were substantially higher. The 2023 seawater survey recorded concentrations of up to 0.04Bq l-1 in the eastern Irish Sea. Elsewhere concentrations were generally below 0.02Bq l-1 . The predominant source of caesium-137 to the Irish Sea is considered to be remobilisation into the water column from activity associated with seabed sediment (Hunt, Leonard & Hughes 2013). Discharges from Sellafield have decreased substantially since the commissioning of the SIXEP waste treatment process in the mid‑1980s, and this has been reflected in a decrease in caesium-137 concentrations in shoreline seawater at St Bees (Figure 8.9). In more recent years, the rate of decline of caesium‑137 concentrations over time has been decreasing at St Bees. Longer time series showing peak concentrations in the Irish Sea, and, with an associated time-lag, the North Sea are also shown in Figure 8.9.

Figure 8.9(a). Concentration of caesium-137, in Bq l-1 in the Irish Sea.

Figure 8.9(b). Concentration of caesium-137, in Bq l-1 in the North Sea.

Figure 8.9(c). Concentration of caesium-137, in Bq l-1 in shoreline seawater close to Sellafield at St. Bees.

In 2024, caesium-137 concentrations were reported as less than values (or close to the less than value) in the western English Channel (including those near the Channel Islands) and were not distinguishable from the background of fallout from nuclear weapons testing (Figure 8.5).

A full assessment of historic long-term trends of caesium-137 in surface waters of Northern European seas is provided elsewhere (Povinec and others 2003).

Tritium concentrations in North Sea seawater in 2024 are shown in Figure 8.6 and were generally similar than those observed in 2022 (Environment Agency, Food Standards Agency and others 2021) due to the influence of discharges from Sellafield and other nuclear sites. As in previous North Sea surveys, tritium concentrations were positively detected in a few water samples taken from the most southerly sampling locations of the North Sea and measured just above the less than value in 2024. The most probable source is most likely to be from the authorised discharges of tritium from nuclear power plants located in the vicinity (including those on the English Channel coast). For comparison, the background concentration of tritium from natural and industrial sources (but excluding fallout from nuclear weapons testing) in seawater from the North Atlantic Ocean is estimated to be 0.05Bq l-1 (Jean-Baptiste and others 2018). In industrial activity, however, tritium is not normally removed from effluent prior to discharge, and locally elevated tritium concentrations in seawater of around 1 to 2 Bq l-1 have been observed near nuclear sites (for example, (Jean-Baptiste and others 2018)).

In the Bristol Channel, the combined effect of historical tritium discharges from the Maynard Centre, the former GE Healthcare Limited facility at Cardiff[footnote 9], and those from Berkeley, Oldbury, and Hinkley Point, is shown in Figure 8.7. Tritium concentrations in the Bristol Channel were low in 2024 (all below 4Bq l-1 ). Most results are reported as less than values (or close to the less than value) in the vicinity of the Welsh coast. Overall, tritium concentrations were lower in the inner region of the Bristol Channel, in comparison to recent years. There is no evidence of tritium entering the Irish Sea from the combined effect of discharges from the former GE Healthcare Limited facility at Cardiff, Berkeley, Oldbury, and Hinkley Point. Discharges from the Pharmaron UK radiolabelling facility, in Cardiff, also provide a minor contribution of tritium to this area. Tritium concentrations in the western English Channel were all reported as below the less than value (or close to the less than value) (Figure 8.8).

Technetium-99 concentrations in seawater have decreased following the substantial reduction in discharges resulting from discharge abatement. This followed substantial increases observed from 1994 to their most recent peak in 2003. The results of research cruises to study this radionuclide have been published (K. Leonard and others 1997; K. S. Leonard and others 1997; McCubbin and others 2002; Leonard and others 2004; Leonard and others. 2008) and an estimate of the total inventory residing in the sub-tidal sediments of the Irish Sea has also been published (Jenkinson and others 2014). Trends in plutonium and americium concentrations in seawater of the Irish Sea have also been published (Leonard and others 1999).

Full reviews of the quality status of the north Atlantic and a periodic evaluation of progress towards internationally agreed targets have been published by OSPAR (OSPAR 2000; OSPAR 2009; OSPAR 2010; OSPAR 2016). The fifth periodic evaluation covers both radioactive discharges from the nuclear and non-nuclear sectors and environmental concentrations and demonstrated that Contracting Parties successfully fulfilled the RSS objectives for the nuclear and non-nuclear sectors (OSPAR 2022).

Shoreline sampling was also carried out around the UK, as part of routine site and regional monitoring programmes. Much of the shoreline sampling was directed at establishing whether the impacts of discharges from individual sites are detectable. Where appropriate, these are reported in the relevant sections of this report, and the results are collated in Table 8.10. Most radionuclides are reported as less than values. Tritium and caesium-137 concentrations remote from site discharge points are consistent with those in Figure 8.4 to Figure 8.8.

SEPA took a series of marine sediments and seawater samples across the Pentland Firth. All radionuclides were reported as less than (or close to the limit of detection). The results are presented in Table 8.11.

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Smith, D., Smith, B., Joyce, A. & McMeekan, I., 2002, An assessment of aquatic radiation exposure pathways in Northern Ireland. SR(02)14. RL 20/02, Lowestoft.

Smith, J.G.. & Simmonds, J.R.. (Editors), 2009, The methodology for assessing the radiological consequences of routine releases of radionuclides to the environment used in PC-CREAM 08: HPA-RPD-058, Health Protection Agency, Chilton.

Smith, K.R. & Jones, A.L., 2003, ‘Generalised Habit Data for Radiological Assessments, NRPB-W41’.

Statutory Instruments, 2007, SI 2007 No. 3236. The Radioactive Contaminated Land (Northern Ireland) (Amendment) Regulations 2007.

Statutory Instruments, 2010, 2010 No. 2145. The Radioactive Contaminated Land Regulations (Northern Ireland) (Amendment) Regulations 2010.

Statutory Instruments, 2016, The Water Supply (Water Quality) Regulations 2016. SI No. 614.

Statutory Rules of Northern Ireland, 2017, The Water Supply (Water Quality) Regulations (Northern Ireland) 2017, 52.

Statutory Rules of Northern Ireland, 2018, SR 2018 No 116. The Radioactive Substances (Modification of Enactments) Regulations (Northern Ireland) 2018.

Swift, D., 1995, ‘A laboratory study of 239,240Pu, 241Am and 243,244Cm depuration by edible winkles (Littorina littorea L.) from the Cumbrian Coast (NE Irish Sea) radiolabelled by the Sellafield discharges’, Journal of Environmental Radioactivity, 27(1), 13–33.

Swift, D., 2002a, Radioactivity in uncommon seafoods, Lowestoft. Environment Report RL16/02.

Swift, D., 2002b, The dry cloth airborne radioactivity surveillance programme: Summary of results 19995-2001 and overview of the whole programme 1973-2001. Lowestoft, Environment Report RL23/02.

Swift, D.J. & Nicholson, M.D., 2001, ‘Variability in the edible fraction content of 60Co, 99Tc, 110mAg, 137Cs and 241Am between individual crabs and lobsters from Sellafield (north eastern Irish Sea)’, Journal of Environmental Radioactivity, 54(3), 311–326.

Uddin, S., Behbehani, M., Fowler, S.W., Al-Ghadban, A. & Dupont, S., 2019, ‘Assessment of loss of 210Po from fish and shrimp by cooking and its effect on dose estimates to humans ingesting seafood’, Journal of Environmental Radioactivity, 205–206, 1–6.

UK Statutory Instruments, 2018, SI 2018 No. 1278. The Ionising Radiation (Basic Safety Standards) (Miscellaneous Provisions) (Amendment) (EU Exit) Regulations 2018.

UK Statutory Instruments, 2019, The Conservation of Habitats and Species (Amendment) (EU Exit) Regulations 2019.

United Kingdom - Parliament, 1965, Nuclear Installations Act, 1965.

United Kingdom - Parliament, 1985, Food and Environment Protection Act 1985.

United Kingdom - Parliament, 1993, Radioactive Substances Act, 1993.

United Kingdom - Parliament, 1995a, Environment Act 1995.

United Kingdom - Parliament, 1995b, Review of Radioactive Waste Management Policy: Final Conclusions, London.

United Kingdom - Parliament, 2004, Energy Act 2004.

United Kingdom - Parliament, 2009, Marine and Coastal Access Act 2009.

United Kingdom - Parliament, 2016, Environmental Permitting (England and Wales) Regulations. Statutory Instrument 2016 No 1154.

United Kingdom - Parliament, 2017, The Ionising Radiations Regulations 2017. Statutory Instrument 2017 number 1075.

United Kingdom - Parliament, 2018, Environmental Permitting (England and Wales) (Amendment) (No. 2) Regulations. Statutory Instrument 2018 No 428.

United Kingdom - Parliament, 2020a, The Environmental Permitting (England and Wales) (Amendment) (EU Exit) Regulations 2019, 1(39).

United Kingdom - Parliament, 2020b, The Waste and Environmental Permitting etc. (Legislative Functions and Amendment etc.) (EU Exit) Regulations 2020. Statutory Instrument 1540.

Watson, S., Jones, A., Oatway, W. & Hughes, J., 2005, Radiation Exposure of the UK Population: 2005 Review. HPA-RPD-001, Chilton.

Welsh Statutory Instruments, 2018, The Water Supply (Water Quality) Regulations 2018, 60.

Young, A., McCubbin, D., Thomas, K., Camplin, W., Leonard, K. & Wood, N., 2003, 210Po Concentrations in UK Seafood, in P. Warwick (ed.), 9th International Symposium on Environmental Radiochemical Analysis, 18-20 September 2002. Oxford, ERA II, 143–149, Royal Society of Chemistry, London.

Young, A.K., McCubbin, D. & Camplin, W.C., 2002, Natural Radionuclides in Seafood. Project R03010/C0808. RL 17/02, Lowestoft.

Appendix 1 Disposals of radioactive waste

Tables A1.1 to A1.4 downloadable in Open Document Spreadsheet (ODS) Format on the main RIFE page

Summary of unintended leakages, spillages, emissions or unusual findings of radioactive substances from nuclear licensed sites in the UK in 2024 (see Table A1.5 in the ODS file)

AWE Aldermaston, April 2024

Summary of incident

AWE reported a higher than expected tritium value in April 2024. AWE’s investigation found a faulty spent tritium target container to be the likely cause of the elevated discharge.

Consequences and actions taken

The April 2024 tritium discharge value was a very minor increase on the normal monthly discharges. The Environment Agency were satisfied with AWE’s explanation. No action was required.

AWE Aldermaston, June 2024

Summary of incident

AWE reported a higher than expected tritium value in June 2024. AWE reported that this was due to maintenance being undertaken on the particle accelerator facility.

Consequences and actions taken

The June 2024 tritium discharge value was a very minor increase on the normal monthly discharges. The Environment Agency were satisfied with AWE’s explanation. No action was required.

Berkeley, 2024

Summary of incident

Inaccurate gaseous emissions were recorded with an increasing trend in gaseous emissions since 2022 although still significantly below the permitted limits.

Consequences and actions taken

The Environment Agency investigation is currently underway.

NRS believe that the inaccurate data being recorded is a result of changing a counting machine and entering data into the wrong column of a table as a result.

NRS believe the upward trend in beta particulate and carbon-14 gaseous emissions is a result of a rise in background concentrations.

Berkeley, 2024

Summary of incident

A passive air sampler (‘Tacky shade’ – Swift 2002b) located on the perimeter fence was vandalised and the equipment is no longer sitting at the correct height above ground level which may lead to a skew in monitoring results.

Consequences and actions taken

This is currently under investigation by Environment Agency.

Dounreay, June 2024

Summary of incident

Nuclear Restoration Services (NRS) notified SEPA of possible loss of radioactively contaminated water to the ground from the Carbon Bed Filter (CBF) structure located within the Fuel Cycle Area.

Consequences and actions taken

NRS’ investigation concluded that there was a small leak from the CBF. NRS has subsequently removed water from the structure and installed level monitoring equipment. In July 2025 SEPA issued a regulatory notice requiring NRS to undertake a review of existing groundwater monitoring arrangements, assess compliance with the requirement to dispose of radioactive waste via an authorised route, undertake characterisation to establish the extent of the radioactive contamination and develop a programme for undertaking the appropriate remediation.

Dounreay, August 2024

Summary of incident

NRS informed SEPA that very low levels of radioactivity had been identified in samples taken from a sump collecting water ingress within a non-radioactive facility on the Dounreay site. The arrangements in place at the time involved the intercepted water being pumped from the sump and discharged to the marine environment via the non-active drainage system, which is not an authorised route for the disposal of liquid radioactive waste. NRS subsequently undertook work to estimate the annual volume discharged from the sump and the radionuclide components present.

Consequences and actions taken

At time of writing SEPA is considering the matter.

Dungeness A, March 2024

Summary of incident

In March 2024, during drone inspection, and further close-up inspections, Nuclear Restoration Services (NRS) identified a small gap in the ventilation ductwork associated with the Wet Waste Transfer Facility (WWTF). The calculated maximum estimated release was less than 1% of the total stack flow, which would be within the tolerance of the sampling equipment and flow measurements of the stack. Using the worst-case scenario release, and assuming the gap was present since the plant went into operation in January 2023, the potential discharge of key radionuclides was estimated to be a tiny fraction of the total discharge. NRS report suggests that this event would not have affected the gaseous discharges reported monthly by the site.

Consequences and actions taken

At the time of writing, a Radioactive Substances Compliance Assessment Report (RASCAR) is to be issued shortly by the Environment Agency which includes non-compliance for 2.3.2(c) and 2.3.4 (a). Despite the fact there was no significant environmental impact, this event had the potential to have a minor environmental effect, as the event resulted in an uncontrolled release from an unauthorised route.

Heysham 1, March 2024

Summary of incident

Elevated activity levels of Co-60 were detected at two high volume air samplers at Heysham 1. Although elevated levels of Co-60 had been detected, there was no breach of permit condition 3.1.2 in that the emissions did not exceed 10% of the annual 100MBq limit. Despite a thorough investigation, Heysham 1 could not identify the source of the Co-60. Possible causes have been speculated such as a contaminated component being moved, knocked or banged during transport, or a release of gas with particulate contamination from a pressurised facility such as the fuelling machine.

Consequences and actions taken

The Environment Agency were satisfied with the scope of the investigation and the additional measures put in place by Heysham 1 to closely monitor the situation. No non-compliances to the permit were identified.

Heysham 1, June 2024

Summary of incident

EDFE-NGL reported that elevated activity levels of Co-60 were discharged to air via the Reactor 1 contaminated vent at Heysham 1 Power Station. Discharges of Co-60 at Heysham 1 are typically below minimum detectable activity but at the time of the incident, a discharge of 2.7MBq occurred. Although elevated levels of Co-60 had been detected, there was no breach of permit condition 3.1.2 in that the emissions did not exceed 10% of the annual 100MBq limit. It is thought that the introduction of the air-powered cutting tool as a novel operation within the Irradiated Fuel Dismantling facility (IFDF) caused an increased flow and dispersion of the particulate matter through the vent.

Consequences and actions taken

In response to the incident, optioneering has been undertaken at Heysham 1 to implement HEPA standard filtration for the IFDF in air operations. The Environment Agency have completed their investigation, and the enforcement response was advice and guidance. There were negligible environmental impacts as a result of this incident.

Sellafield, July 2024

Summary of incident

The Analytical Services (AS) facility requires constant ventilation to maintain contamination control. Between July and September 2024, a number of holes were identified caused by the corrosion of the external ductwork (post abatement) that caused a discharge of gaseous radioactive waste to the environment prior to the permitted disposal outlet.

Consequences and actions taken

On 30 July 2024 the Environment Agency observed that the holes identified to date were repaired and confirmed that the 4-weekly maintenance inspections had been carried out. On 1 October 2024 Sellafield Limited (SL) initiated a 2-year refurbishment programme of the external ductwork. Environment Agency served a Regulation 36 enforcement notice on 11 October 2024 specifying the steps required that SL need to take to return to compliance with the permit conditions and issued a formal written warning as the enforcement response to the permit non-compliances.

Sizewell B, November 2024

Summary of incident

On 1 November 2024 Environment Agency were notified by the Operator (EDF) that during routine inspections they discovered that a small section of the gaseous waste ducting (leading into the main stack) on the Auxiliary building roof had corroded through. This caused a discharge of radioactive waste to the environment prior to the permitted disposal route. This section of ducting is located downstream of the filtration abatement system, before joining the main vent stack.

Consequences and actions taken

On 15 November 2024 the Environment Agency received written confirmation from EDF that the corroded pipework was repaired and returned to high standards. Environment Agency completed its investigation into the corroded pipework event and subsequently issued a formal written warning as the enforcement response to the permit non-compliances. There were negligible environmental impacts relating to this event.

Appendix 2 Abbreviations and Glossary

ABL

AWE plc, Babcock and Lockheed Martin UK

AGIR

Advisory Group on Ionising Radiation

AGR

Advanced Gas-cooled Reactor

AWE

Atomic Weapons Establishment

BAT

Best Available Techniques

BEIS

Department of Business, Energy and Industrial Strategy

BNFL

British Nuclear Fuels plc

BPM

Best Practicable Means

BSS

Basic Safety Standards

BSSD 13

Basic Safety Standards 2013

CCFE

Culham Centre for Fusion Energy

CEDA

Consultative Exercise on Dose Assessments

Cefas

Centre for Environment, Fisheries & Aquaculture Science

COMARE

Committee on Medical Aspects of Radiation in the Environment

CoRWM

Committee on Radioactive Waste Management

DAERA

Department of Agriculture Environment and Rural Affairs

DCO

Development Consent Order

Defra

Department for Environment, Food and Rural Affairs

DESNZ

Department for Energy Security & Net Zero

DPAG

Dounreay Particles Advisory Group

DSRL

Dounreay Site Restoration Limited

DWPF

Decommissioning Waste Processing Facility

Euratom

European Atomic Energy Community

EASR18

Environmental Authorisations (Scotland) Regulations 2018

EIA

Environmental Impact Assessment

ENRMF

East Northants Resource Management Facility

EPR

Environmental Permitting Regulations

EPR 16

Environmental Permitting (England and Wales) Regulations 2016

EPR 18

Environmental Permitting (England and Wales) Regulations 2018

EPR 19

Environmental Permitting (England and Wales) Regulations 2019

EPRTM

European Pressurised Reactor™

EU

European Union

FEPA

Food and Environment Protection Act

FSA

Food Standards Agency

FSS

Food Standards Scotland

GDA

Generic Design Assessment

GDF

Geological Disposal Facility

GES

Good Environmental Status

GRR

Guidance on Requirements for Release of Nuclear Sites from Radioactive Substances Regulation

HAW

Higher Activity Radioactive Waste

HEPA

High-Efficiency Particulate Filters

HMNB

His Majesty’s Naval Base

HPA

Health Protection Agency

HSE

Health and Safety Executive

IAEA

International Atomic Energy Agency

ICRP

International Commission on Radiological Protection

ILW

Intermediate Level Waste

ILWS

Intermediate Level Waste Store

IRPA

International Radiation Protection Association

IRR 17

Ionising Radiations Regulations 2017

ISO

International Standards Organisation

JET

Joint European Torus

LLLETP

Low Level Liquid Effluent Treatment Plant

LLW

Low-Level Waste

LLWF

Low Level Radioactive Waste Facility

LLWR

Low Level Waste Repository

LoA

Letter of Agreement

LoD

Limit of Detection

MAST

Mega Amp Spherical Tokamak

MOD

Ministry of Defence

MRF

Metals Recycling Facility

MSSS

Magnox Swarf Storage Silo

NCA

Nuclear Cooperation Agreement

ND

Not Detected

NDA

Nuclear Decommissioning Authority

NDAWG

National Dose Assessment Working Group

NEAES

North-East Atlantic Environment Strategy

NIEA

Northern Ireland Environment Agency

NORM

Naturally Occurring Radioactive Material

NRPB

National Radiological Protection Board

NRS

Nuclear Restoration Services Limited

NRTE

Naval Reactor Test Establishment

NRW

Natural Resources Wales

NWS

Nuclear Waste Services

OBT

Organically Bound Tritium

ONR

Office for Nuclear Regulation

OSPAR

Oslo and Paris Convention for the Protection of the marine environment of the North-East Atlantic

PRAG(D)

Particles Retrieval Advisory Group (Dounreay)

PHE

Public Health England

PWR

Pressurised Water Reactor

RAPs

Reference Animals and Plants

RDP

Repository Development Programme

RIFE

Radioactivity in Food and the Environment

RRDL

Rosyth Royal Dockyard Limited

RNAS

Royal Naval Air Station

RRSL

Rolls-Royce Submarines Limited

RSA 93

Radioactive Substances Act 1993

RSR

Radioactive Substances Regulation

RSR 18

Radioactive Substances (Modification of Enactments) Regulations (Northern Ireland) 2018

RSS

Radioactive Substances Strategy

SAC

Special Area of Conservation

SEPA

Scottish Environment Protection Agency

SFL

Springfields Fuels Limited

SILWE

Solid Intermediate Level Waste Encapsulation plant

SIXEP

Site Ion Exchange Effluent Plant

STW

Sewage Treatment Works

THORP

Thermal Oxide Reprocessing Plant

UCP

Urenco ChemPlants Limited

UKAEA

United Kingdom Atomic Energy Authority

UKHSA

UK Health Security Agency (formerly PHE and HPA)

UKNNL

UK National Nuclear Laboratory

UOC

Uranium Ore Concentrate

UNS

Urenco Nuclear Stewardship Limited

UUK

Urenco UK Limited

VLLW

Very Low-Level Waste

WILWREP

Wet Intermediate Level Waste Retrieval and Encapsulation Plant

Absorbed dose

The ionising radiation energy absorbed in a material per unit mass. The unit for absorbed dose is the gray (Gy) which is equivalent to J kg-1.

Artificial radionuclides

These are radioactive isotopes that are not found readily in nature. They are generally produced during nuclear power generation, nuclear fuel reprocessing, from nuclear weapons testing or in specialist devices by neutron bombardment.

Authorised premises

These are premises that has been authorised by the environment agencies to discharge to the environment.

Becquerel

One radioactive transformation per second.

Bioaccumulation

Excretion may occur; however, the rate of excretion is less than the rate of intake + accumulation.

Biota

Flora and fauna.

Canteen meals

Canteen meals are used to represent a typical or mixed diet at locations remote from nuclear sites throughout the UK. Prior to leaving the EU, these data were collected and reported to comply with Articles 35 and 36 of Euratom. These samples are maintained to demonstrate compliance with Euratom recommendations. Additional information is provided in Section 2.1.3.

Committed effective dose

The sum of the committed equivalent doses for all organs and tissues in the body resulting from an intake (of a radionuclide), having been weighted by their tissue weighting factors. The unit of committed effective dose is the sievert (Sv). The ‘committed’ refers to the fact that the dose is received over a number of years, but it is accounted for in the year of the intake of the activity.

Direct radiation

Ionising radiation which arises directly from processes or operations on premises using radioactive substances and not as a result of discharges of those substances to the environment.

Dose

Shortened form of ‘effective dose’ or ‘absorbed dose’.

Dose limits

Maximum permissible dose resulting from ionising radiation from practices covered by the Euratom Basic Safety Standards Directive, excluding medical exposures. It applies to the sum of the relevant doses from external exposures in the specified period and the 50 year committed doses (up to age 70 for children) from intakes in the same period. Currently, the limit has been defined as 1mSv per year for the UK.

Dose rates

The radiation dose delivered per unit of time.

Effective dose

The sum of the equivalent doses from internal and external radiation in all tissue and organs of the body, having been weighted by their tissue weighting factors. The unit of effective dose is the sievert (Sv).

Environmental materials

Environmental materials include freshwater, grass, seawater, seaweed, sediment, soil and various species of plants.

Equivalent dose

The absorbed dose in a tissue or organ weighted for the type and quality of the radiation by a radiation-weighting factor. The unit of equivalent dose is the sievert (Sv).

External dose

Doses to humans from sources that do not involve ingestion or inhalation of the radionuclides.

Fuel-free verification

Fuel-free verification is when all of the spent fuel has been certified as being removed from the site.

Fragments

‘Fragments’ are considered to be fragments of irradiated fuel, which are up to a few millimetres in diameter.

Ionising radiation

Radiation composed of particles that individually carry enough kinetic energy to liberate an electron from an atom or molecule, ionising it. Ionising radiation is generated through nuclear reactions, either artificial or natural, by very high temperature (for example, plasma discharge or the corona of the Sun), via production of high energy particles in particle accelerators, or due to acceleration of charged particles by the electromagnetic fields produced by natural processes, from lightning to supernova explosions.

Indicator materials

Environmental materials may be sampled for the purpose of indicating trends in environmental performance or likely impacts on the food chain. These include seaweed, soil and grass.

In-growth

Additional activity produced as a result of radioactive decay of parent radionuclides.

Kerma air rate

Air kerma is the quotient of the sum of the kinetic energies of all the charged particles liberated by indirectly ionising particles in a specified mass of air.

Millisievert

The millisievert is a 1/1000 of a sievert. A sievert is one of the International System of Units used for the measurement of dose equivalent.

Non-nuclear sites

These are other sites that use radioactive materials, such as hospitals, research of industrial facilities.

NORM

Naturally occurring radioactive materials that may have been technologically enhanced in some way. The enhancement has occurred when a naturally occurring radioactive material has its composition, concentration, availability, or proximity to people altered by human activity. The term is usually applied when the naturally occurring radionuclide is present in sufficient quantities or concentrations to require control for purposes of radiological protection of the public or the environment.

Nuclear Sites

Shortened form of ‘Nuclear Licensed sites’.

Orphan source

Is a radioactive source which is neither exempted nor under regulatory control. For example, this could be because it has never been under regulatory control or abandoned, lost misplaced, stolen or otherwise transferred without proper approval.

Permits and authorisations

In England and Wales, the term ‘permit’ replaced ‘authorisation’ under the Environmental Permitting Regulations (EPR). In this report ‘permit’ has been used to apply to all sites in England and Wales, irrespective of whether the period considered includes activities prior to EPR coming into force in 2010. In Scotland, the term ‘permit’ replaced ‘authorisation’ under the Environmental Authorisations (Scotland) Regulations 2018 (EASR18), irrespective of whether the period includes activities prior to EASR18 coming into force in 2018. ‘Authorisation’ remains the relevant term for Northern Ireland.

Radiation exposure

Being exposed to radiation from which a dose can be received.

Radiation weighting

Factor used to weight the tissue or organ absorbed dose to take account of the type and quality of the radiation. Example radiation weighting factors: alpha particles = 20; beta particles = 1; photons = 1.

Radioactivity

The emission of alpha particles, beta particles, neutrons and gamma or x-radiation from the transformation of an atomic nucleus.

Radionuclide

An unstable form of an element that undergoes radioactive decay.

Representative person

Representative person is an approach used in the assessment of radiation exposures (‘total doses’) to the public. Direct measurement of doses to the public is not possible under most normal conditions. Instead, doses to the public are estimated using environmental radionuclide concentrations, dose rates and habits data. The estimated doses are compared with dose criteria. In this report, the dose criteria are legal limits for the public.

Source specific dose

An assessment of dose that focuses on specific sources on sites (for example, liquid or gaseous discharges) and their associated pathways (for example, external exposure over shoreline areas). See Section 2, and Appendix 4 for more information on these dose calculations.

In some cases, assessments may include the impacts from multiple sites. For example, the source specific assessment of the Dumfries and Galloway coast includes the impacts of discharges from Chapelcross and Sellafield.

Tissue weighting factors

Factor used to weight the equivalent dose in a tissue or organ to take account of the different radiosensitivity of each tissue and organ. Example tissue weighting factors: lung = 0.12; bone marrow = 0.12; skin = 0.01.

‘Total dose’

An assessment of dose that takes into account all exposure pathways such as radionuclides in food and the environment and direct radiation.

Appendix 3. Modelling of concentrations of radionuclides in foodstuffs, air, and sewage systems

A3.1. Foodstuffs

At Sellafield and the LLWR, a simple food chain model has been used to provide concentrations of activity in milk and livestock for selected radionuclides to supplement data obtained by direct measurements. This is done where relatively high limits of detection exist or where no measurements were made.

Activities in milk, meat and offal were calculated for technetium-99, ruthenium-106, cerium-144, and plutonium-241 using the equations:

Cm = Fm Ca Qf and

Cf = Ff CaQf where

Cm is the concentration in milk (Bq l-1),

Cf is the concentration in meat or offal (Bq kg-1(fresh)),

Fm is the fraction of the animal’s daily intake by ingestion transferred to milk (d l-1)

Ff is the fraction of the animal’s daily intake by ingestion transferred to meat or offal (d kg-1 (fresh)),

Ca is the concentration in fodder (Bq kg-1 (dry)),

Qf is the amount of fodder eaten per day (kg (dry) d-1)

No direct account is taken of radionuclide decay or the intake by the animal of soil associated activity. The concentration in fodder is assumed to be the same as the maximum observed concentration in grass or, in the absence of such data, in leafy green vegetables. The food chain data for the calculations are given in Table A3.1 (Simmonds, Lawson & Mayall 1995; Brenk and others no date) and the estimated concentrations in milk, meat and offal are presented in Table A3.2.

A3.2. Air

For some sites, discharges to air may lead to significant doses. Doses may arise from radionuclides transferred from the plume to food crops and animal products, inhalation of radionuclides in the plume itself and external doses from radionuclides in the plume.

Average annual concentrations of radionuclides in the air at nearest habitations were calculated using a Gaussian plume model, PC CREAM 08 (Smith & Simmonds 2009), and the reported discharges of radionuclides to air. Each site assessment uses generic meteorological data based on the Pasquill stability category shown in Table A3.3. The core modelling assumptions (such as the effective discharge or stack height and distance to habitation) are also shown in Table A3.3. The discharge stack is assumed to be at the centre of the site. For multi-station sites (for example, Sizewell A and B), the gaseous discharges are summed together and assumed to be discharged via a common discharge point (at the centre of both sites).

External radiation doses from radionuclides in the plume and from deposited activity were calculated taking into account occupancy levels indoors and outdoors and location factors to allow for building shielding. During the time people are assumed to be indoors, the standard assumption that the dose from gamma-emitting radionuclides in the plume will be reduced by 80% has been made. Internal radiation doses from inhalation of discharged radionuclides were assessed using breathing rates. Doses were initially assessed for 3 age groups: adults, children (10-year-old), and infants (1-year-old). All ages are assumed to have year-round occupancy at the nearest habitation. The assumptions of the inhalation and occupancy rates assessment are shown in Table A3.4. The dose to the prenatal children age group was taken to be the same as that for an adult.

A3.3. Sewage systems

The facilities at AWE Aldermaston and the Grove Centre, Amersham discharge liquid radioactive waste to local sewers. Wastes are processed at local sewage treatment works (STW). The prolonged proximity to raw sewage and sludge experienced by sewage treatment workers could lead to an increase in the dose received, via a combination of external irradiation from the raw sewage and sludge and the inadvertent ingestion and inhalation of resuspended radionuclides.

An assessment of the dose received by workers at the Maple Lodge STW, near Amersham and the Silchester STW, near Aldermaston has been conducted using the methodology and data given by the Environment Agency (Paul and others. 2022a; Paul and others 2022b). The flow rate through the sewage works is used to calculate a mean concentration in raw sewage and sludge of each nuclide discharged. These mean concentrations are combined with habits data concerning the workers’ occupancy near raw sewage and sludge, external and internal dosimetric data, and physical data such as inhalation rates to provide dose estimates. Workers are assumed to spend 75% of a working year in proximity to the raw sewage, and the other 25% in proximity to the sewage sludge. Where liquid discharges are not nuclide-specific, a composition has been assumed based on advice from the operators and concentrations calculated accordingly.

The model parameters and habits data used to assess the dose to sewage treatment workers are given in Table A3.5 and the amounts of radioactivity discharged from each site can be found in Appendix 1 of this report.

Appendix 4. Consumption, inhalation, handling and occupancy rates

This appendix gives the consumption, handling and occupancy rate data used in the source specific assessment of exposures from terrestrial consumption and aquatic pathways. Consumption rates for terrestrial foods are based on (Byrom and others 1995) and are given in Table A4.1. These are derived from national statistics and are taken to apply at each site. Site-specific data for aquatic pathways based on local surveys are given in Table A4.2. These site-specific data have been supplemented with referenceable generic information (Environment Agency 2002; Smith & Jones 2003) where appropriate. Occupancy over intertidal areas and rates of handling from local surveys has been reassessed to take account of a change in the factor used to determine the range of rates typical of those most exposed. For using the ‘cut-off’ method to define those most exposed (Preston, Mitchell & Jefferies 1974; Hunt, Hewett & Shepherd 1982) a factor of 3.0 is used to describe the ratio of the maximum to the minimum rate within the group. Data used for routine assessments of external and inhalation pathways from gaseous discharges are given in Appendix 3.

Consumption rates refer to the mass of a foodstuff as prepared for consumption (with, for example, stalks or shells removed) and are consistent with the mass quantity used for presentation of concentration data in this report. The term ‘fresh weight’ is used in the data tables of concentrations. For shellfish, the consumption rates and concentrations are for cooked weights. For other foodstuffs, uncooked weights are used.

Appendix 5. Dosimetric data

The dose coefficients used in assessments in this report are provided in Table A5.1 for ease of reference. For adults and postnatal children, they are based on generic data contained in ICRP Publication 119 (International Commission on Radiological Protection 2012). Dose coefficients for prenatal children have been obtained primarily from ICRP 88 (International Commission on Radiological Protection 2001) and NRPB (Oatway and others 2008). For a few radionuclides where prenatal dose coefficients are unavailable the relevant adult dose coefficient has been used.

In the case of tritium, polonium, plutonium and americium radionuclides, dose coefficients have been adjusted according to specific research work of relevance to assessments in this report.

A5.1. Polonium

The current ICRP advice is that a gut uptake factor of 0.5 is appropriate for dietary intakes of polonium by adults (International Commission on Radiological Protection 1994). A study involving the consumption of crab meat containing natural concentrations of polonium-210 has suggested that the factor could be as high as 0.8 (Hunt & Allington 1993). More recently, similar experiments with mussels, cockles and crabs suggested a factor in the range 0.15 to 0.65, close to the ICRP value of 0.5 (Hunt & Rumney 2004; Hunt & Rumney 2005; Hunt & Rumney 2007). Previous assessments have considered the effects of a factor of 0.8 for considering monitoring results in RIFE. In view of the most recent review (Hunt & Rumney 2007), a value of 0.5 has been adopted for all food, consistent with ICRP advice.

A5.2. Plutonium and americium

Studies using adult human volunteers have suggested a gut uptake factor of 0.0002 is appropriate for the consumption of plutonium and americium in winkles from near Sellafield (Hunt, Leonard & Lovett 1986; Hunt, Leonard & Lovett 1990). For these and other actinides in food in general, a factor of 0.0005 is considered as a reasonable best estimate (National Radiological Protection Board 1990). These values are to be used if data are not available for the specific circumstances under consideration. In this report, a gut uptake factor of 0.0002 is used for plutonium and americium, for estimating doses to consumers of winkles from Cumbria and this is consistent with UKHSA advice. For other foods and for winkles outside Cumbria, the factor of 0.0005 is used for these radionuclides. This choice is supported by studies of cockle consumption (Hunt 1998).

A5.3 Technetium-99

Volunteer studies have been extended to consider the transfer of technetium-99 in lobsters across the human gut (Hunt, Young & Bonfield 2001). Although values of the gut uptake factor found in this study were lower than the ICRP value of 0.5, dose coefficients are relatively insensitive to changes in the gut uptake factor. This is because the effective dose is dominated by ‘first pass’ dose to the gut (Harrison & Phipps 2001). In this report, we have therefore retained use of the standard ICRP factor and dose coefficient for technetium-99.

A5.4. Tritium

In 2002, UKHSA reviewed the use of dose coefficients for tritium associated with organic material (D. Harrison, Khursheed & E. Lambert 2002). Subsequently, UKHSA published a study of the uptake and retention of organically bound tritium (OBT) in rats fed with fish from Cardiff Bay (Hodgson and others 2005). These experiments suggested that the dose coefficient for OBT in fish from the Severn Estuary near Cardiff should be 6.0 x 10-11 Sv Bq-1, higher than the standard ICRP value for OBT ingestion. The higher value is used for adults in the assessment of seafood collected in the Bristol Channel in this report, and the standard ICRP value for other assessments. This approach is consistent with advice (Cooper 2008) which takes account of the conclusions reached by the Independent Advisory Group on Ionising Radiation (AGIR) concerning relative biological effectiveness and radiation weighting (Health Protection Agency 2007). Thereafter, results of uptake experiments involving adult volunteers, who ate samples of sole from Cardiff Bay, provided further evidence that this approach is indeed cautious (Hunt, Bailey & Reese 2009).

A5.5. Nuclear data

The nuclear data (half-life, mean beta and gamma energies) have been updated to values presented in ICRP 107 (Endo, Yamaguchi & Eckerman 2005; Endo 2005; Endo & Eckerman 2007; International Commission on Radiological Protection 2008) from ICRP 38 (International Commission on Radiological Protection 1983) data. The nuclear data are primarily used to calculate external dose rates over mud and sand where gamma dose rates are below background or highly variable. The differences in external doses at several sites using ICRP 38 and ICRP 107 were calculated, the differences in dose were less than 5%. The Environment Agency has produced a document that includes radionuclide information, such as the sources, uses, modes of release and nuclear decay data (Environment Agency 2003).

Appendix 6. Estimates of concentrations of natural radionuclides

A6.1. Aquatic foodstuffs

Table A6.1 gives estimated values of concentrations of radionuclides due to natural sources in aquatic foodstuffs. The values are based on sampling and analysis conducted by Cefas (Young, McCubbin & Camplin 2002; Young and others 2003). Data for lead-210 and polonium-210 are quoted as medians with observed minimum and maximum values given in brackets. Dose assessments for aquatic foodstuffs are based on concentrations of these radionuclides net of natural background.

The carbon-14 concentrations are adjusted to take account of the dilution of natural atmospheric carbon-14 by the emission of carbon dioxide from fossil fuel burning. A dilution of 0.28% for each part per million of carbon dioxide added due to fossil fuel burning is used (Graven & Gruber 2011). Values for the carbon dioxide additions are taken each year from: National Oceanic and Atmospheric Administration carbon dioxide annual mean data (in ppm).

The initial specific activity of carbon-14 was 256Bq kg-1 (Ministry of Agriculture Fisheries and Food 1995). In 2024, the adjusted value used as the basis for Table A6.2 was 209Bq kg-1.

A6.2. Terrestrial foodstuffs

The values of carbon-14 in terrestrial foodstuffs due to natural sources that are used in dose assessments are given in Table A6.2 and based on earlier data (Ministry of Agriculture Fisheries and Food 1995). The value for the specific activity of carbon-14 in 2024 (given in Section A6.1) was used to derive these estimates.

Appendix 7. Research in support of the monitoring programmes

The environment agencies, FSA and FSS have programmes of special investigations and supporting research and development studies to complement the routine monitoring programmes. This additional work is primarily directed at the following objectives:

  • to evaluate the significance of potential sources of radionuclide contamination of the food chain and the environment
  • to identify and investigate specific topics or pathways not currently addressed by the routine monitoring programmes and the need for their inclusion in future routine monitoring
  • to develop and maintain site-specific habits and agricultural practice data, to ensure that dose assessment calculations reflect the real-world situation
  • to develop more sensitive and/or efficient analytical techniques for measurement of radionuclides in natural matrices
  • to evaluate the competence of laboratories’ radiochemical analytical techniques for specific radionuclides in food and environmental materials
  • to develop improved methods for handling and processing monitoring data

Other studies include projects relating to effects on wildlife, emergency response and planning and development of new environmental models and data.

Information on ongoing and recently completed extramural research is presented the list below (and in Table A7.1, available on the main RIFE page. Those sponsored by the Environment Agency and FSA are also listed on their websites: Environment Agency, and Food Standards Agency, respectively. Copies of the final reports for each of the projects funded by the FSA are available from 11th Floor, 64 Victoria Street, London, SW1E 6QP. Further information on studies funded by SEPA is available by emailing RSEnquiries@sepa.org.uk. Environment Agency reports are available from Environment Agency. A charge may be made to cover costs.

Extramural projects

  • Soil and herbage survey, reference UKRSR01 and SCO00027, on behalf of the Environment Agency and SEPA, due Q4, 2025
  • Offshore Dose Assessment Model, SEPA, due Q3, 2024
  • Thorium Transfer Work, SEPA - the intent is to publish on the SEPA website, in accordance with accessibility requirements, in 2025
  • NORM Biota Project, SEPA - the intent is to publish on the SEPA website, in accordance with accessibility requirements, in 2025
  • McGuire, C (2023). Radiological Protection of the Public from Radioactive Particles (PhD Thesis). University of Stirling. SEPA. The official completion date of McGuire, C. (2023) is 25th January 2023. It is now available in the University of Stirling repository McGuire Thesis on University of Stirling thesis repository
  • Clyde Estuary Assessment, SEPA, due Q2, 2025
  • Soil and herbage follow-up, SEPA, complete Q1, 2024
  • Coastal Monitoring, SEPA - the intent is to publish on the SEPA website, in accordance with accessibility requirements, in 2025
  • Shetland Background Sampling, SEPA - the intent is to publish on the SEPA website, in accordance with accessibility requirements, in 2025
  • SW Scotland Background Sampling, SEPA - the intent is to publish on the SEPA website, in accordance with accessibility requirements, in 2025
  • Partitioning Behaviour of Radionuclides in Sewer Systems, Environment Agency, due Q3, 2024
  • Radionuclide Transfer Parameter Review, Environment Agency, due Q4, 2024
  • Behaviour of Colloids in Radioactive Waste Transfer and Dispersion in Aqueous Environments, Environment Agency, due Q1 2025
  • Aerial Monitoring of Environmental Radioactivity, Environment Agency - the work is complete and is awaiting publication on the gov.uk website
  • Investigation of the fate and behaviour of lutetium-177 in the environment, Environment Agency, due Q1 2025 – the work is complete and is awaiting publication on the gov.uk website

In 2024/25, the following reports have been published.

Main Report Footnotes

  1. The Environment Agency has an agreement with Natural Resources Wales (NRW) to undertake some specific activities on its behalf including radiological environmental monitoring and Radioactive Substances Regulation of nuclear sites in Wales. ↩

  2. At some locations separate nuclear sites are situated adjacent to one another, for example some EDF Energy operated power stations have a neighbouring Nuclear Restoration Services decommissioning station. As these are operated by different employers, workers at one station are considered to be members of the public for the purpose of assessing direct radiation exposure to the other station. Doses to workers are considered differently to those for the public and therefore are not included in ‘total dose’ assessments. ↩

  3. The Cumbrian coastal community are exposed to radioactivity resulting from current and historical discharges from the Sellafield site, the Low Level Waste Repository (LLWR) and historical discharges of naturally occurring radionuclides from the former phosphate processing plant near Whitehaven. ↩

  4. Natura 2000 is made up of sites designated as Special Areas of Conservation (SACs) and Special Protection Areas (SPAs). SACs and SPAs in the UK no longer form part of the EU’s Natura 2000 ecological network. The 2019 Regulations have created a national site network on land and at sea, including both the inshore and offshore marine areas in the UK. ↩

  5. The reference to proprietary products in this report should not be construed as an official endorsement of those products, nor is any criticism implied of similar products which have not been mentioned. ↩ ↩2

  6. Values are rounded to 2 significant figures, or 3 decimal places, depending on their magnitude. ↩

  7. Contributions are rounded to the nearest percent. ↩

  8. ‘Particles and objects’ are terms used which encompass discrete radioactive items which can range in radioactivity concentration, size and origin. ‘Particles’ include radioactive scale, fragments of irradiated nuclear fuel and incinerated waste materials (less than 2mm in diameter). ‘Objects’ are larger radioactive artefacts and stones which have radioactive contamination on their surface and are larger than 2 mm in size. ↩

  9. GE Healthcare ceased manufacturing tritium and carbon-14 radiolabelled compounds at its premises, the Maynard Centre, in Cardiff in 2009 and 2010, respectively. Its custom radiolabelling division was acquired by Quotient Bioresearch (Radiochemicals) Ltd in 2010, and subsequently by Pharmaron UK Ltd in 2017. This operation is located at a new premises in Cardiff under a non-nuclear permit, albeit at lower levels compared to the historic discharges from the Maynard Centre. ↩ ↩2 ↩3

  10. The FEPA Order was made in 1997 following the discovery of fragments of irradiated nuclear fuel on the seabed near Dounreay, by United Kingdom atomic energy authority (UKAEA), and prohibits the collection of seafoods within a 2km radius of the discharge pipeline. ↩

  11. DPAG was set up in 2000, and PRAG(D) thereafter, to provide independent advice to SEPA and United Kingdom atomic energy authority (UKAEA) on issues relating to the Dounreay fragments. ↩

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