Corporate report

Regulatory scrutiny and engagement for geological disposal: annual report 2024 to 2025

Updated 16 October 2025

Foreword

The Environment Agency is the independent environmental regulator for the nuclear industry in England. Our activities are guided by our plan ‘EA2030 change for a better environment’. This plan acts as our compass, enabling us and others to chart a course towards a healthier, greener and more prosperous country.

Our EA2030 plan sets out 3 strategic goals:

• healthy air, land and water supporting nature’s recovery
• sustainable growth
• a nation resilient to climate change

Our regulation of disposals of radioactive waste, including radioactive discharges to air and water, and disposal of solid waste to land, aligns with these goals. It helps ensure that these facilities are designed and operated in ways which minimise waste and protect the environment.

The Office for Nuclear Regulation (ONR) is the UK’s independent nuclear regulator for safety, security and safeguards at licensed nuclear sites in the UK. Our mission is to protect society by securing safe nuclear operations.

ONR has the legal authority to regulate nuclear safety, nuclear security, safeguards and conventional health and safety at the 36 licensed nuclear sites in Great Britain. We also regulate the safety of transporting radioactive materials.

This is a joint Environment Agency and ONR publication that summarises our work relating to geological disposal of radioactive waste during 2024 to 2025. As regulators for these wastes, we are working together to make sure that any future geological disposal facility (GDF) will meet the high standards for environmental protection, safety, safeguards and security that the law requires, and the public expects.

We have established agreements with Nuclear Waste Services (NWS), the organisation responsible for developing a GDF, to provide regulatory advice and to scrutinise its work. We are engaging with NWS early, before regulation starts, so that when a site is identified, NWS already clearly understands what it needs to do as part of the regulatory process. We also liaise with NWS to make sure that it gives the right advice to waste producers about packaging radioactive waste for future disposal at a GDF. This helps NWS understand what it needs to do to meet applicable legal requirements for environmental protection, safety, radioactive materials transport, safeguards and security. Early engagement also helps us better understand NWS’s work and lets us prepare in advance for any permit or licence applications we might receive from NWS, so that we can respond promptly and knowledgeably.

We have no regulatory role in selecting potential sites for a GDF. However, we support communities that are considering hosting a GDF on matters relating to our respective areas of regulation.

We have set out our regulatory expectations for geological disposal, covering our respective remits. The Environment Agency has issued its guidance on requirements for authorisation (GRA)^{[footnote 1]}. In 2024 to 2025, the Environment Agency consulted on an updated version of the GRA, however, references to the GRA in this report refer to the 2009 published version. ONR has issued a technical assessment guide on geological disposal^{[footnote 2]}, which it updated in March 2023. It will also draw on relevant aspects of the Safety Assessment Principles for Nuclear Facilities (SAPs)^{[footnote 3]}, the Security Assessment Principles for the Civil Nuclear Industry (SyAPs)^{[footnote 4]} and the Construction (Design and Management) Regulations 2015.

As independent regulators, we are committed to making our work open and transparent. This report will help us to continue to do this.

Find further information on the Environment Agency’s role in Regulating the geological disposal of radioactive waste: environmental protection and ONR’s engagement on the GDF.

Executive summary

This report summarises the work that the Environment Agency and the ONR carried out to scrutinise Nuclear Waste Services’ (NWS’s) work related to geological disposal, and our associated interactions with the public from April 2024 to March 2025.

NWS kept us informed on developments to the Geological Disposal Facility (GDF) Programme throughout 2024 to 2025. In summer 2024, NWS told us of a delay in planned submission dates for its intrusive investigation permit and Development Consent Order (DCO) applications. We currently plan to receive the first permit application in about 2028. However, we recognise that there is significant uncertainty relating to the potential impacts of the 2025 government spending review on the GDF Programme and the currently limited portfolio of potential host communities. 

Important factors in the case for new nuclear and engendering public confidence are demonstrating that the industry is able to effectively manage the complete lifecycle of nuclear facilities through site clean-up and restoration, combined with the appropriate treatment and disposal of spent fuel and higher activity wastes. Both the Environment Agency and ONR believe that providing a final disposal solution is a crucial enabler in achieving this. Final disposal facilities are becoming a reality for a number of established nuclear countries. These nations are demonstrating a clear commitment to completing the lifecycle for higher activity waste by implementing a final solution. As part of our submission to the Nuclear Regulatory Taskforce in spring 2025, commissioned by the Department for Energy Security and Net Zero (DESNZ), the Environment Agency advised that the implementation of a GDF, along with fit-for-purpose and sustainable options for managing lower activity waste, are considered as part of the energy infrastructure priority, alongside the new build programme and the development of new technologies. 

Our pre-application advice and scrutiny during 2024 to 2025 covered a wide range of topics, including:

• NWS’s developing management arrangements for holding an intrusive investigation permit
• the scope of our permit requirements for intrusive investigations
• site descriptive models of the Copeland and Theddlethorpe areas and site characterisation plans
• NWS’s strategy for developing the GDF design and environmental, safety, security and safeguards safety cases
• NWS’s strategy for demonstrating optimisation of radiological protection and the use of best available techniques (BAT)
• disposability advice NWS provides to waste producers
• NWS’s research, development and demonstration plan

The Environment Agency made significant progress in preparing to regulate a GDF. We consulted on the UK environment agencies updated guidance on the requirements for authorisation of disposal facilities for solid radioactive waste (the GRA) and our guidance for staged regulation of a GDF, and we aim to publish final versions in 2026. We also continue to build our capability to ensure that we can regulate a GDF over the coming decades.

Regulators have no role in the siting process for a GDF. However, we have continued to attend events in the Mid and South Copeland and Theddlethorpe Community Partnership areas to explain our role in geological disposal and our regulatory processes. The Theddlethorpe Community Partnership closed in June 2025, after the period covered by this report. We also hold our own stakeholder engagement events throughout the year at which geological disposal is discussed.

Introduction

Radioactive waste has been, and continues to be, produced from the UK’s historic and current nuclear power, research and defence programmes, as well as from industries, hospitals and universities that use radioactive material.

There is currently no available route in the UK to dispose of the most hazardous radioactive waste, so it is stored on existing nuclear sites until a solution can be implemented.

UK government policy for the implementation of geological disposal of the UK’s most hazardous radioactive waste is described in the 2024 UK policy framework for managing radioactive substances and nuclear decommissioning ^{[footnote 5]}. This sets out the framework for implementing geological disposal in England and Wales. Scottish Government policy does not support geological disposal. Rather, its policy is for the long-term management of higher activity waste (HAW) in near-surface facilities that are located as near to the site where the waste is produced as possible.

The Nuclear Decommissioning Authority (NDA) is responsible for implementing government policy on the long-term management of radioactive waste. Nuclear Waste Services (NWS), which is part of the NDA Group, is responsible for developing a GDF.

The Environment Agency and ONR are responsible for making sure that any future GDF in England or (for ONR only) Wales meets the high standards necessary to protect people and the environment when it is being developed, while it is operating, and after it has closed.

We will be responsible for granting the necessary environmental permits and nuclear site licence, and for our respective regulatory roles of environmental protection, safety, security, radioactive materials transport and safeguards. Regulatory oversight of a GDF is likely to be required for at least 150 years.

Our regulatory partner, Natural Resources Wales (NRW), has similar environmental protection responsibilities for Wales, and we keep them aware of matters arising and important outcomes from our work.

We are engaging with NWS now to make sure that any future applications to develop a GDF take account of all permitting and licensing requirements. We also want to make sure that NWS gives the right advice to waste producers, so that radioactive waste packaged at their sites is suitable for future disposal, can be safely stored pending disposal, and can be safely transported to a future disposal site.

Discussions at this early stage will help us prepare in advance for any permit or licence application we might receive from NWS, so that we can respond promptly and knowledgeably.

In addition, it ensures that the waste producers and NWS fully understand our regulatory expectations and can provide adequate documentation to support any future applications.

At this stage, before considering issuing permits or a licence, we are providing regulatory advice rather than making regulatory decisions. We have no regulatory role in selecting potential sites for a GDF.

Regulatory preparations

Engaging with NWS on geological disposal at an early stage helps us prepare for any environmental permit or nuclear site licence application that we might receive, so that we can respond promptly to what will be a first-of-a-kind activity.

We anticipate that regulated activities will continue for around 150 years from the start of the construction of a GDF, during its operation and through to its final closure. Regulation of the development, operation and eventual closure of a GDF will take place in stages. Approval is required from regulators for surface-based intrusive investigations, and, in due course, for underground investigations, construction, operation and closure. The developer is not able to progress from one stage to the next without first securing the relevant permissions it needs. The purpose of this staged approach to regulation is to ensure that the development is carried out safely and securely at all times, and in ways that ensure that people and the environment are properly protected without inadvertently undermining the long-term performance of the facility.

The regulatory process will start when the developer wants to carry out surface-based intrusive investigations such as drilling boreholes. At this stage, the developer will need to apply to the Environment Agency for an environmental permit before starting any such works. Joint regulation by the Environment Agency and ONR will begin after a preferred site for a GDF has been identified. The developer will need to apply for both a nuclear site licence and the appropriate environmental permit before starting excavations to enable underground investigations.

We recognise that regulatory responsibilities and requirements may change and evolve during the design, construction, operation, closure and post-closure periods of a GDF. There could also be changes in government policy on waste disposition routes. We give advice and scrutiny based on the latest knowledge, directions and legal requirements. We maintain and enhance our capabilities to meet our responsibilities in regulating geological disposal. This includes engaging with other regulators and international programmes relevant to radioactive waste disposal.

Permitting and guidance

The Environment Agency finalised the consultation versions of the UK environment agencies updated guidance on the requirements for authorisation of disposal facilities for solid radioactive waste (the GRA) and our guidance for staged regulation of a GDF ahead of a joint public consultation in 2024. The public consultation started in November 2024 and concluded in February 2025. Whilst the consultation was live, we held a virtual stakeholder event in January 2025. At the event, we explained the reasons for the consultation and how stakeholders could provide relevant responses. We received more than 600 comments from around 50 organisations and individuals on these documents.

Following the conclusion of the joint consultation on the GRA and staged regulation guidance, we collated the responses we received onto a central repository. This will enable us to analyse them, log the main issues and draft a short narrative to support our publication of the responses in 2025. After that, we will analyse the responses further so we can make relevant changes ahead of finalising both guidance documents.

We completed a draft intrusive investigation permit template and issued it to NWS for review and comment. We will consult the public on any future permit application that we receive.

We communicated to NWS our position on the following:

• regulation of deep geotechnical boreholes
• definition of geological baseline conditions for intrusive investigation boreholes
• our expectations for compliance with the Environmental Permitting Regulations (EPR) surrender tests for the intrusive investigation permit
• construction activities likely to be permitted during the underground investigations stage

We will consider feedback on these positions that we received through the GRA and staged regulation guidance consultation.

We also agreed an indicative position that pre-intrusive investigation boreholes drilled to investigate the Quaternary geology to enable siting of the intrusive investigation drilling rigs would not fall within the scope of our regulation as a radioactive substances activity.

Capability building

We recognise that the permitting of geological disposal is a first-of-a-kind activity. Therefore, while regulating geological disposal is similar to ongoing regulatory activities, it also has some significant differences. It is necessary to enhance regulatory capabilities to align with the stages in permitting a GDF, and to maintain these capabilities over extended periods during the design, construction and operation of the facility.

The Environment Agency is continuing to review and develop its capability to ensure that we can regulate a GDF over the coming decades, starting with getting ready to permit the intrusive investigations. We carried out an internal capability assessment, which was informed by several internal planning workshops during 2024 to 2025. We used this information to develop a programme to increase staff numbers and capability in significant areas in the period leading up to the first permit application, including use of the external supply chain. We drafted a review plan for the intrusive investigation permit application and supporting initial site evaluation (ISE). We will have the opportunity to trial this review plan and processes when reviewing a first draft permit application that NWS plans to provide to us in 2025 to 2026.

We also strengthened our links with our National Infrastructure Team, who will lead our response as a statutory consultee to the intrusive investigation DCO.  

We continue to attend internal and external training seminars on topics of relevance to geological disposal. In 2024 to 2025, this included:

• an internal training seminar on NWS’s portfolio of communities
• an update on Copeland and Theddlethorpe geological understanding provided by NWS
• a seminar given by ENSI, the Swiss regulator of geological disposal, on its regulatory approach to site investigations carried out by the developer, Nagra, in support of its site selection process

• attending virtual international seminars providing training and learning from experience, including:

  • EU Pre-disposal management of radioactive waste (PREDIS) online training, summarising its insights into topics relating to pre-disposal management of radioactive waste
  • EU European Joint Programme on Radioactive Waste Management (EURAD) seminar on information, data and knowledge management for geological disposal
  • the International Atomic Energy Agency (IAEA) Methods for Radiological and Environmental Impact Assessment (MEREIA) virtual webinar on processes related to the transport of radionuclides in groundwater and generic methods for estimating radionuclide concentrations in water from radioactive discharges into surface water
  • IAEA webinars on the siting process for disposal facilities for spent fuel and high level waste and the Swedish disposal programme
• dissemination of learning from our international engagement

Five members of staff attended the Geological Society’s Energy Group Conference on Geological Disposal of Radioactive Waste in June 2024. At this meeting, we presented on the importance of geological knowledge in regulatory submissions underpinning the permitting of geological disposal. NWS subsequently asked us to give this presentation to members of its Geoscientists Forum in December 2024.

We also attended the NWS Research Support Office (RSO) conference in January 2025, and an Environment Agency staff member presented a poster on their PhD research on the effect of curing temperature on Nirex reference vault backfill cement.

International engagement

During 2024 to 2025, both the Environment Agency and ONR engaged with other regulators and international programmes relevant to geological disposal, both in person and virtually. This engagement provided us with valuable information and learning from international organisations, GDF developers and regulators from countries that are in various stages of GDF siting and development.

The Environment Agency is a member of the Nuclear Energy Agency (NEA) Integration Group for the Safety Case (IGSC). In this capacity, we were part of the organising committee for, and attended, the NEA Safety Case Symposium 2024: ‘Moving towards the construction of a safe deep geological repository – getting real’.

The Environment Agency also:

• attended the IAEA Joint Convention on the safety of spent fuel and radioactive waste management meeting in March 2025, which provided an opportunity to gain detailed insights into international GDF development programmes and regulator planning and engagement
• attended the Grimsel Test Site 40th Anniversary conference in Switzerland, which provided learning about underground GDF research from a wide range of international organisations
• attended the International Conference on Clays in Natural and Engineered Barriers for Radioactive Waste Confinement, providing useful learning on international GDF development programmes in clay host rocks and research on clay based engineered barriers and rock
• engaged with ENSI, the Swiss regulator, to learn about its experiences in regulating Nagra’s recent site selection activities

ONR participated in the NEA’s Expert Group on Public Communication of Nuclear Regulatory Organisations September 2024 meeting in Finland, which included a visit to Olkiluoto Island where a GDF is under construction. During this visit, we toured the current disposal facility for low and intermediate level waste and met with Teollisuuden Voima Oyj, a Finnish nuclear power company that operates the facility, and with the local Mayor to gain insights into their stakeholder engagement strategies and community relations approach. This knowledge exchange provided valuable insights into international best practice in nuclear waste management communications.

Geological disposal programme

We expect NWS to have a clear and comprehensive programme of work to implement geological disposal that meets our regulatory requirements, and to demonstrate progress against it (GRA Requirement 4). We recognise that such a programme also needs to meet other requirements in addition to regulatory matters. However, these wider needs are not part of our regulatory responsibilities and so do not form part of the scope of our work.

This programme should give us confidence that NWS understands what it needs to do to achieve its goals at each phase of its work. It should also enable us to plan and focus our scrutiny work, assess NWS’s progress towards meeting our requirements, and ensure we can put in place regulatory resources when required.

We engage with NWS at quarterly GDF Programme meetings and at supporting technical and keep in touch meetings. At the start of 2024 to 2025, we advised NWS that we were concerned about a lack of detailed planning information in some areas. This information is important for the Environment Agency to plan our engagement activities in the period leading up to the intrusive investigation permit applications and to prepare for review of the applications and ISEs. We were also concerned that our engagement in a number of areas was focused on meetings rather than on providing documents on which we can formally comment, which was hindering our ability to provide more enduring regulatory advice.

In response, NWS provided us with more detailed planning information, including 12-month rolling plans that it updates on a quarterly basis. This information has been useful in informing our planning, in particular for NWS’s preparations for site investigation and the first permit application, although the programme information is less detailed for future financial years. We anticipate receiving an increased number of documents on which we can formally provide regulatory comment during 2025 to 2026.

In summer 2024, NWS informed us of a delay in planned submission dates for its intrusive investigation permit and DCO applications by about a year. We currently expect to receive the first permit application in about 2028. However, we recognise that there is continued uncertainty relating to the effects of the June 2025 government spending review settlement for the next few years. NWS will need to review the implications of the spending review on the GDF Programme during quarters 2 and 3 of 2025 to 2026.  

We also recognise that NWS needs to manage considerable uncertainty in its portfolio of potential host communities. In March 2025, East Lindsey District Council formally withdrew from the Theddlethorpe GDF Community Partnership. In June 2025, Lincolnshire County Council followed suit, resulting in the closure of the community partnership and ending the siting process in this area.

The Environment Agency provided comments on an NWS-commissioned contractor review of its regulator engagement, which examined all areas of our engagement with NWS. We were pleased that the report identified a number of issues that we have previously raised with the GDF Programme team, including the need for detailed work programmes to be agreed with regulators, formalised management of actions, dissemination of information and a repository for shared documents. NWS is already acting upon some of these recommendations. However, we noted that the contractor report appeared to consider that regulators are NWS’s stakeholders, and it did not identify the fundamental differences that exist between NWS’s interactions with the Environment Agency as the Low Level Waste Repository (LLWR) permit holder and as a future GDF permit holder, and non-regulatory stakeholders. We referred NWS to principles for pre-application engagement on the GDF Programme between NWS and regulators that we agreed jointly in 2021 to 2022.

Organisational capability and development

The developer and operator of a GDF should foster and nurture a positive organisational culture (promoting safety, security and environmental compliance) at all times. It should also have a suitable management system, organisational structure and enough resources to provide essential functions (GRA Requirement 4, LC 17 and 36).

The Environment Agency needs to be confident that NWS can comply with environmental permit requirements before we issue environmental permits for borehole investigations at potential sites.

NWS must also continue to develop its organisational capability and management systems, so that it is capable of meeting the requirements of environmental permits and a nuclear site licence to construct and operate a GDF.

ONR recognises that NWS is not currently close to submitting a licence application for a GDF, and its organisation is being developed for the next tranche of work. Our current focus is on providing advice on the management arrangements and processes needed to support a capable organisation in line with the requirements of our licence conditions.

An important organisational change in April 2024 was the integration of the Low Level Waste Repository (LLWR) Ltd and Radioactive Waste Management (RWM) Ltd businesses into a new single legal entity, Nuclear Waste Services Ltd. Through 2024 to 2025, the Environment Agency and ONR continued with a programme of engagement with NWS on the development of its organisational arrangements to implement the GDF Programme within this new structure.

Over the year, the focus of our engagements on the GDF Programme organisational arrangements was on providing regulatory advice to NWS on developing elements of the management system that will support the first permit application, currently planned in about 2028. NWS is using consultants to support evaluation of the maturity of these elements and to support their development.

Quality management arrangements, the Integrated Management System (IMS) and quality assurance (QA)

NWS provided us with an overview of its integrated management system (IMS) and its arrangements for conducting ‘tier 2’ independent internal audit and assurance. Following the move to a single legal entity, these arrangements are integrated across NWS. Although the initial phases of transition are complete, at the time of assessment there was potentially a further 2 to 3 years of work before the systems are fully integrated as intended. We noted that:

• the IMS is now up and running - at a high level this looks to be fit-for-purpose, although we noted that a number of legacy documents (procedures) remain in place
• the quality management functions are now established and functioning, although at the time of assessment a number of staff vacancies still remained
• internal audit arrangements are in place, with an annual audit programme defined

Competence management, learning and development

NWS is progressing with the development of harmonised (NWS-wide) arrangements for competency management. An NWS talent learning and development (L&D) function has been established, and a new L&D and competency management policy put in place. Training records across both former LLWR and RWM organisations have been consolidated into a single learning management IT system, and associated work on training staff in the use of the system is underway.

NWS is developing a 2-year plan to implement competency assessment and management across the organisation. NWS plans this to be complete in advance of the first permit application. The developing arrangements build upon existing LLWR systems, which were developed to achieve regulatory compliance.

Governance, records management, knowledge and information management

NWS outlined to us its GDF Programme arrangements for governance, knowledge and information management, and records management. These appear well developed and largely mature. At the time of assessment, there were some transfer activities still to complete to bring them onto the NWS integrated management system. However, records management was still being carried out separately for the LLWR and GDF sides of the NWS business. NWS committed to integrate arrangements by the end of 2024 to 2025.

Contract management, and NWS’s developing intelligent client and intelligent customer arrangements

NWS set out to us its commercial strategy and intelligent client arrangements. This establishes a common approach to the supply chain for NWS businesses. The intelligent client role is supported by specialist subject matter experts (SMEs) and intelligent customer (IC) roles to ensure that supply chain work is correctly specified, monitored and delivered. At the time of assessment, both intelligent customer and intelligent client arrangements were currently being rolled out and embedded (through post-single legal entity harmonisation), with a target for completion by the end of 2025.

In comparison to the LLWR business and its use of the supply chain, the GDF Programme will entail greater scope and longer schedules, with bespoke arrangements where necessary. For example, for the major permissions delivery partner (MPDP), it has adopted a joint venture approach, whereas the initial phase of site characterisation work is proposing to use a 5-supplier framework. Both models will employ sub-contracting. NWS recognises the need to access learning from experience (both internal and external) to ensure best practice is employed, and to ensure its contract managers, SMEs and ICs are sufficiently suitably qualified and experienced persons to ensure effective delivery.

Contract management, and particularly the effectiveness of IC arrangements, will be a priority for our readiness evaluations as the GDF programme moves towards its application for the first permit.

Disposal system development, design authority and requirements management, environmental leadership

NWS presented an overview of its arrangements for developing the GDF design, including developing the design authority role, design development configuration and change management, and requirements management. These are relatively mature arrangements, now established in the NWS IMS, drawing largely on processes established in its predecessor organisation RWM, with additional harmonisation with LLWR processes underway in some areas.

Overall, these arrangements looked to be fit-for-purpose, although we note that the test of whether or not they are effective will be when we carry out our first permit readiness assessments in 2025 to 2026. At that time, we will also assess the equivalent arrangements relating to the intrusive site investigation phase of the GDF Programme, for which the site characterisation team is responsible.

Management of organisational change arrangements

NWS outlined its approach to managing organisational change. This currently follows existing (legacy) arrangements from LLWR and RWM, but it is working to integrate these into a new system over the next few months, under the existing OSHENS safety management platform. Beyond this, NWS is looking to apply the system to all change, not just organisational change.

Site characterisation delivery partner (SCDP)

NWS planned to put this major contract to tender in autumn 2025, with selection of the SCDP by the end of 2027. We recognise that this will be reviewed as part of the consideration of the spending review settlement. The contract will run for 10 years, with options to extend by a further 3 x 5 years. NWS will set the scope and the organisational and governance framework within which the SCDP will work (although the SCDP and its contractors will develop detailed operational arrangements). NWS will act as intelligent customer, carry out performance monitoring and assurance activities, and maintain ownership of permit compliance. We will be monitoring the development and implementation of these arrangements via our organisational development work stream.

Preparing for intrusive investigations

As specified in our staged regulation process for geological disposal, NWS will need to apply to the Environment Agency for an environmental permit to carry out the drilling of deep site investigation boreholes. The applications must take full account of our environmental permitting requirements (GRA section 5). Based on current planning assumptions, we anticipate receiving applications for up to 2 sites around 2028, and we are currently developing our guidance on staged regulation and the permitting templates (see Regulatory preparations).

NWS will also require a DCO to begin the intrusive investigations. The Environment Agency is a statutory consultee in this process.

Advice on major permissions

The Environment Agency is providing advice to NWS on our requirements for the intrusive investigation permit application and the supporting initial site evaluation (ISE).

We attended monthly major permissions implementation proposals meetings with NWS throughout the year and provided regular updates to NWS on progress concerning development of our guidance and permit template documents. We informed NWS of our decision to incorporate the ISE and PESE (preliminary environmental safety evaluation) guidance as an appendix in the staged regulation guidance document.

We explained how we propose to assess compliance against the environmental permit surrender tests and also the suitability of NWS’s determination of baseline conditions. On the basis of information NWS has provided to us so far, we expect that it can provide the necessary evidence that polluting substances will not be used during borehole drilling and also that it can seal decommissioned boreholes to the standard that will satisfy our requirement to return the site to its original state. However, we will examine this in more detail when we receive a permit application. Looking forward, we await information from NWS on how it will determine geological/hydrogeological baseline conditions for the intrusive investigation boreholes.

We briefed NWS about our public consultation on the GRA and staged regulation guidance documents ahead of the launch of the joint public consultation.

We informed NWS about the separate consultation on our charging scheme, and that changes we have made will enable us to recover costs on a time and materials basis for our regulatory effort during the investigatory stages of a future GDF.

NWS provided us with a summary of the current planned ISE document structure and timeline for important activities/milestones/documents leading up to its submission. We will use this to update our engagement plan for the period leading up to the submission of the intrusive investigation permit application(s). NWS has provided an updated, but still draft, schedule for 2025 to 2028, covering high level activities leading up to the intrusive investigation permit application. It has also included 2 versions of the draft ISE and permit application.

We met with NWS in February 2025 to start engagement on the intrusive investigation DCO consultation.

In April 2024, NWS gave us an overview of its approach to developing safety concepts while the level of geological uncertainty is high. This included discussion of a generic set of ‘safety concept classes’ developed by NWS, as well as discussion on the definition and use of ‘containment-providing rock zones’ in other organisations, and the potential limitations of such an approach in the geological environments NWS is currently considering. We agreed that follow up engagement on this topic is required, with a meeting to be scheduled after NWS has commented on the consultation draft groundwater chapter of the GRA.

Site evaluation

Regulators are independent of the site selection and evaluation process, but we will provide advice on matters relevant to our respective regulatory remits.

NWS updated us on progress towards its recommendation to government due late 2025 to 2026 relating to the site or sites to take forward for intrusive investigation. NWS’s evaluation process considers safety and security, environment, transport, community, engineering feasibility and value for money in each potential area. In January 2025, it announced its ‘areas of focus’ for further study and investigation. These included potential locations for the disposal facility, accessways and surface site in the 3 community partnership areas.

Site understanding

The potential GDF host rock of interest in Copeland and Theddlethorpe is in the inshore area, that is the underground part of the facility which would be located deep below the seabed, but within the outer limit of UK territorial waters at around 22 km offshore.

NWS needs to demonstrate sufficient understanding of the geological and hydrogeological environment to justify its proposals for intrusive investigations. It is developing site descriptive models (SDMs) for Copeland and, prior to closure of the Theddlethorpe Community Partnership, for Theddlethorpe to summarise the existing knowledge of the areas of focus. These will provide the data required to underpin the evaluation topics, for example, geological, hydrogeological and geotechnical data, and to identify information gaps and uncertainties that it will need to address in its developing safety cases. The SDMs will be based initially on desk-based information, the results of a marine seismic survey of the geology in the inshore region off the Copeland coast during summer 2022, and the results from legacy seismic surveys in the Copeland and Theddlethorpe regions that NWS has purchased and reprocessed.

The Environment Agency met with NWS twice in 2024 to 2025 to understand its developing SDMs for Copeland and Theddlethorpe. We also received version 0.1s of both SDMs. We did not formally review these documents because by that time NWS was nearing completion of the next versions (v1.0s). However, we did assess the documents to determine progress towards meeting our requirements for the ISE and we provided feedback to NWS at a meeting in March 2025. We concluded that:

• NWS has made considerable progress in developing the SDMs version 0.1s and they contain good quality scientific information
• NWS has made considerable efforts to obtain all the available geoscientific information of relevance to the Copeland and Theddlethorpe areas of focus - however, there are gaps where data either doesn’t exist or are unobtainable, for example, due to commercial constraints - NWS will not be able to address most of these gaps until it commences the intrusive investigations
• NWS has further work to do in integrating the conclusions of its site understanding, and clearly identifying significant uncertainties and data gaps (information requirements), which need to be addressed in the site investigation and NWS’s RD&D programme - this information will provide essential underpinning for NWS’s design and safety case development
• NWS will update the SDM throughout the site investigation - it needs to prepare a fixed version that underpins the intrusive investigation permit application
• we will review NWS’s procedures for managing changes to the SDMs and for management of data prior to the permit application
• we support NWS’s suggestion of preparing a synthesis report to underpin the ISE, which will be more accessible than the SDM documents and in line with international good practice

We raised concerns that NWS was carrying a significant number of geoscience vacancies at the end of 2024 to 2025. We will review NWS’s strategic workforce plan, technical competence and management of contractors during our permit readiness review.

We expect to receive the version 1.0 SDMs and relevant procedures for review in 2025 to 2026.

Site investigation programme development

The Environment Agency expects NWS to have appropriate plans and procedures in place to carry out the site investigation and characterisation work needed to implement geological disposal, and to inform the safety cases and GDF design and construction (GRA Requirement 11). At this stage, we want to make sure that NWS’s plans and actions for future site investigations are consistent with our permit requirements and would not compromise the integrity of potential GDF sites.

The Environment Agency met with NWS 3 times in 2024 to 2025 to understand its developing site characterisation plans (SCPs) and delivery strategy for Copeland and Theddlethorpe. We also received version 1s of both SCPs. As with the version 0.1 SDMs, we did not formally review these documents because by that time NWS was nearing completion of the next versions (v2s). However, we advised NWS that the focus of our review will be the subsurface site characterisation plan and supporting studies.

We will continue to engage with NWS on its developing SCPs, and we expect to receive the version 2 SCPs and relevant procedures for review in 2025 to 2026. Topics of particular interest to us at the pre-application stage include development of the monitoring strategy, definition of respect distances, development of a toolkit of techniques for borehole sealing and international benchmarking. We will use this information to inform our planning for the management of the site investigation and change control of the intrusive investigation permit. We will also engage with NWS on its arrangements for managing the intrusive investigations, including the site characterisation delivery partner and drilling contractor, during our permit readiness review.

GDF development

NWS’s applications to carry out activities leading to the development a GDF must be consistent with government policy (for example, UK policy framework for managing radioactive substances and nuclear decommissioning), and must comply with relevant legislation (for example, the Environmental Permitting Regulations 2016) and the duties placed on operators of a licensed nuclear site (nuclear safety, security, safeguards, radioactive materials transport, and conventional health and safety).

NWS’s applications should also address regulatory expectations, including those expressed in this report and previous reports in this series, as well as showing awareness of new and emerging regulations and guidance.

Any application for an environmental permit relating to a proposed disposal of solid radioactive waste must be supported by a suitable environmental safety case (ESC) as described in our guidance on requirements for authorisation (GRA) for the disposal of solid radioactive waste. Similarly, any application for a nuclear site licence to construct and operate a GDF will need to be supported by adequate demonstrations of nuclear safety and security.

We want to establish a clear and common understanding with NWS of the requirements of permit and licence applications to make sure that any future applications take full account of our regulatory requirements.

Our engagement during 2024 to 2025 focused on NWS’s strategies for GDF design and safety case development.

Strategy for GDF design and safety case development

During 2024 to 2025, NWS developed and presented its work programme for GDF design and safety case development. The work programme is being updated approximately quarterly, and we are continuing to discuss with NWS the forward programme of information exchange in this area.

We reviewed the documents listed below, and offered our findings:

• GDF Programme design strategy handbook
• Best available techniques (BAT) and as low as reasonably practicable (ALARP) strategy: optimisation of protection
• BAT and ALARP position paper: optimisation of protection
• GDF technical Level 3 strategy: delivery of an environment, safety, security & safeguards case (E3S) for GDF (E3S strategy)
• Disposal system development manual (DSDM)

During our reviews, we made reference, where appropriate, to open Regulatory Issues (RIs) and Regulatory Observations (ROs) (see Annex A List of Regulatory Issues and Observations).

The Environment Agency noted the usefulness of the design strategy handbook, and we identified several areas/topics on which we would wish further engagement, including some that would affect our plans and working methods. Our feedback to NWS on this includes 4 recommendations on issues for it to address in its forward workplan.

The Environment Agency noted that the BAT and ALARP strategy: optimisation of protection and the BAT and ALARP position paper: optimisation of protection provided useful insights into NWS’s developing approaches. We were pleased to note that the strategy is consistent with the position on optimisation for radiological protection agreed with regulators in GDF_RO_002. However, we noted that the function and status of these documents in the context of NWS’s wider documentation scheme was unclear. We therefore requested sight of additional documents, including the environment, safety, security and safeguards case (E3S) strategy, the BAT context report and the BAT case, which we subsequently received. Our feedback on this includes 5 recommendations to NWS.

ONR also provided feedback on the BAT and ALARP strategy, noting that its focus was on the demonstration of BAT, with limited detail on ONR’s expectations for ALARP and how these will be met. We noted that, where ALARP was discussed, the focus was on reducing worker exposure to radiation. We advised that ALARP considerations are wider than just radiological protection and should consider all risks. We also advised that the strategy should set out how the balance between BAT and ALARP requirements will be achieved.

The Environment Agency provided advice to NWS so that its E3S case can be properly aligned with our regulatory requirements. NWS is adopting a systems engineering approach to the development of an E3S case. We are familiar with such approaches, and we have no ‘in principle’ objections to them. There will, however, be aspects that need careful attention when applying such approaches to radioactive waste disposal systems because, in contrast to nuclear power plants, for example, disposal systems include natural (non-engineered) systems. NWS will need to consider the long-term performance of the disposal system when developing the disposal concept and design for the disposal facility. We noted the need for NWS to provide assurance to us that disposal is feasible, and that suitable technology exists.

NWS presented its arrangements for disposal system development, design authority and requirements management in September and took an action to review its response to Regulatory Issue GDF_RI_014 on operational environmental safety assessment in light of developments over the previous year.

NWS presented the fire hazard management in GDF Illustrative Design Internal Note ref. 42985178 which summarises work to ensure that fire hazards (nuclear and conventional) are identified and can be managed effectively. This was provided in response to GDF_RI_015 which sought to ensure that fire hazards are considered as early and as strategically as possible.

In addition to meetings related to these documents and reviews, we have engaged with NWS in meetings to consider:

• introduction to siting factors
• pre-concept ESC
• preparation for site-specific design and safety case
• waste barrier and pathways research
• BAT strategy

The Environment Agency attended the NEA Safety Case Symposium 2024: ‘Moving towards the construction of a safe DGR (deep geological repository) – Getting real’ at which NWS made several presentations on its approaches to, and research on, the development of safety cases. We will continue to engage with NWS, for example, on its development of digital approaches for presenting safety cases. We will also take the opportunity to learn from, and benchmark against, other relevant national and international programmes addressing GDF design and safety case development.

Our engagement on this work area continues into 2025 to 2026, and planned work includes reviewing NWS’s modelling strategy and its site characterisation BAT case template.

Building confidence in NWS’s data and modelling

We closed Regulatory Observation GDF_RO_006 on data and models in 2024. This followed a joint inspection in October 2023, which covered NWS’s response to the RO, its procedures for managing technical data, its modelling strategy and the results of an internal audit of GDF Programme computer modelling procedures^{[footnote 6]}. We will continue to engage with NWS on this topic, and data management and running models will be subject to a future inspection at an appropriate time before the intrusive investigation permit application.

Waste management

Waste producers are responsible for appropriately characterising, segregating, treating and packaging higher activity waste (HAW) to meet the expected waste acceptance criteria of a GDF. The operator of a GDF (along with the consignee) will be responsible for making sure that the consigned waste is consistent with the eventual GDF waste acceptance criteria, including transport and handling (GRA Requirement 13 and LC 4).

NWS provides a disposability assessment process to reduce risk in the waste treatment and packaging process, and to assess whether packaging proposals are compatible with the current geological disposal concept and designs. Through this process, NWS provides disposability advice to waste producers and potential waste producers, for example, nuclear new build, on the packaging of their HAW. This also allows GDF development to be kept in step with plans for, and progress on, waste packaging.

We expect NWS to assess packaging proposals for HAW against clear and consistent published specifications and guidance. This is to assure us that NWS’s disposability advice is underpinned and clearly traceable to its developing GDF requirements and safety case. In turn, we expect waste producing sites to use this advice to make appropriate decisions, consistent with BAT and ALARP principles for the whole waste lifecycle, to ensure that HAW is suitably packaged for handling, transport to, and disposal in a GDF.

We expect NWS to work effectively with waste producers, particularly where there is a need to understand and help resolve tension between near-term waste management priorities on existing nuclear sites (such as site hazard reduction) and longer-term disposability priorities. We also expect NWS to share good practice in waste packaging, including through published guidance to waste producers. We engage with NWS to build confidence that:

• HAW will be packaged in a way that is suitable for transporting to, handling and disposing of at a GDF in line with the safety case and with no, or minimal, reworking
• HAW will be conditioned to a safe, passive, transportable and disposable form as soon as is reasonably practicable
• NWS’s procedures, guidance, specifications and limits encompass the full range of wastes destined for geological disposal and are likely to ensure compliance with permit requirements so that they are acceptable for disposal

Disposability assessment

We held quarterly meetings with NWS to review all aspects of waste management. These meetings covered developments in the disposability assessment process, recent disposability assessment outputs, disposability and waste records assurance work.

In May 2024 we reviewed and provided initial comments to NWS on its draft pre-guidance to waste producers on voidage within waste packaged for the GDF. We will continue to work with NWS as it progresses its programme of updating its more detailed guidance to waste producers.

Integration of disposability assessment with GDF systems engineering

We previously raised Regulatory Issues asking Radioactive Waste Management (RWM), now NWS, to enhance its procedures for assessing novel or innovative packaging proposals (GDF_RI_005) and to develop and maintain a list of disposability assessments and endorsements sensitive to changes in the GDF concept or significant factors in the safety cases (GDF_RI_010).

Following an inspection in 2024, we issued a letter and inspection report to NWS in May closing these 2 Regulatory Issues and recording updated actions in a new issue. GDF_RI_016 was raised and issued with the letter, titled ‘keeping disposability assessments and GDF developments current and consistent’.

We worked with NWS throughout the year as it developed its response to the actions placed. In March 2025, we updated Regulatory Issue GDF_RI_016 to version 2. The update clarified what we wanted NWS to provide to fully address the actions.

Waste package records and assurance

In May 2024 we participated in the NDA Information Governance Programme Regulator’s Forum with particular interest in the management, quality and preservation of higher activity waste records. We followed progress on this and the responsibilities between NDA and NWS on higher activity waste records. Since February 2025, we have participated in the NWS-led HAW Records Community of Practice forum with representatives of nuclear sites who hold the waste inventory. NWS provides updates to us on its records assurance work as part of our quarterly review meetings.

Disposability of high heat generating waste (nuclear material)

We issued a letter to NWS in April 2024 providing our advice on its developing work on plutonium (Pu) disposition disposal package concepts.

In August 2024, we participated in a regulatory workshop with NWS and ONR where the joint NWS and NDA Plutonium Integrated Project Team updated regulators on progress with options development for the disposal of the UK’s stockpile of civil separated plutonium, and on the assessment approach for criticality safety of higher fissile loaded waste products. The workshop included discussion on NWS’s provisional response to the recommendations made in our April letter. This work continues and we will continue to review outputs as they are finalised.

Disposability of high heat generating waste (spent fuel)

We carried out an initial preparatory review of the interim outputs of NWS’s disposability assessment for some of the legacy fuels, fuel bearing materials, and related wastes that are held at the Sellafield site. This work is continuing as part of our scrutiny of NWS’s disposability assessment of various populations of spent fuel that are expected to become waste. This work also supports our regulation of predisposal management of this material at Sellafield, to ensure interim storage and potential conditioning and treatment routes are consistent with our expectations of BAT and ultimate disposability.

Disposability of low heat generating waste

We continue to review progress with the conditioning of low heat generating waste streams via our HAW predisposal regulatory interactions with nuclear sites. We liaise with NWS as necessary to understand the disposability advice and assurance it is providing.   

NWS’s research, development and demonstration

The developer and operator of a GDF needs to carry out timely research, development and demonstration (RD&D) to inform its activities and ensure it fulfils its obligations, such as demonstrating optimisation to keep doses from radiation as low as reasonably achievable or practicable (ALARA or ALARP).

We expect NWS to have a targeted and prioritised RD&D programme in place, informed by wider national and international research or implementation programmes. NWS will need to identify and address in a timely way those issues that require RD&D to meet our requirements. NWS should be clear, through its management process, why the RD&D it carries out is needed and what knowledge gaps it will fill.

During the last few years, we raised concerns with NWS over the lack of a visible coordinated RD&D plan and the potential that cuts to its RD&D budget would increase programme risk as a result of a reduction in information needed to substantiate future safety case claims and arguments [6]. NWS subsequently informed us that it is reorganising its RD&D activities to more closely match the needs of the GDF Programme. However, NWS does not yet fully understand the potential impacts of the government spending review on RD&D, and so we await a better understanding of the impacts on RD&D and the delivery of the GDF.

NWS briefed the Environment Agency on the development of its RD&D strategy in November 2024. This covered NWS’s generic approach to developing its research and how it will move to site-specific research plans. During this meeting we had an update on its RD&D plan which included an overview, the core areas of research, and how it will be informed with a systems engineering approach. This provided useful background to re-starting our engagement on this topic, and we have agreed further engagement during 2025 to 2026.

NWS also gave the Environment Agency an update on its waste, barriers and pathways research in March 2025. This meeting included an overview of the waste barriers and pathways team structure and its core topics of focus. We were given a high-level overview of the work being carried out and planned within the sub teams, which gave us understanding of current and future work.

In 2023, NWS informed us of its ‘experimental hierarchy’ – starting with desk and surface-based work, progressing to laboratory research, then making use of generic underground research laboratories (URLs) and finally site-specific underground investigations [6]. In September 2024, the Environment Agency attended the Grimsel Test Site’s, a URL in Switzerland, 40th anniversary conference. This provided us with useful learning on the use of generic URLs for both developers and regulators as well as on the underpinning science. We received progress updates for the international research projects that NWS contributes to at the Grimsel Test Centre. This includes research into the effects of high temperature on bentonite, materials corrosion tests, gas permeable seal tests, research into colloid formation and migration, and thermodynamic model testing.

The Environment Agency attended NWS’s Research Support Office (RSO) Conference in January 2025 in Bristol. It consisted of working group updates, industry presentations and student presentations. There was also a student poster session. This was a useful conference and provided a good overview of the work being carried out by the RSO.

Support to the siting process

We have no regulatory role in selecting potential sites for a GDF. However, we are:

• providing support to communities that are considering hosting a GDF
• sharing information with community partnerships in Cumberland and Lincolnshire
• advising on matters relating to our respective areas of regulation

As of March 2025, there were 3 GDF community partnerships in England: Mid Copeland, South Copeland and Theddlethorpe. However, prior to publication of this report, Lincolnshire County Council made the decision to withdraw from the Theddlethorpe Community Partnership in June 2025. This followed the withdrawal of East Lindsey District Council from the partnership in March 2025 and ended the siting process in the area.

The potential GDF host rock of interest in Copeland is in the inshore area, that is the underground part of the facility which would be located deep below the seabed, but within the outer limit of UK territorial waters around 22 km offshore.

The Environment Agency’s engagement plan for geological disposal sets out our objectives, stakeholders and activities. These activities include publishing information and infographics, producing materials to use at public exhibitions and online, as well as engaging with groups and community partnership members to explain our role. The information includes:

• a short animation about the regulators’ role in geological disposal available on YouTube
• an overview of the regulatory processes that the Environment Agency and ONR will apply to the development, operation and closure of a GDF in England
• information pages about regulating the geological disposal of radioactive waste: environmental protection on GOV.UK and geological disposal on the ONR website
• our annual reports, including this one

Mid Copeland and South Copeland Community Partnerships

We were not invited to attend any community partnership events or NWS organised events in Cumberland during 2024 to 2025. However, we offered to host a meeting with members of all community partnerships to explain our role and share how we are scrutinising the work of NWS.

In April 2024, NWS shared market research carried out by Yonder in Cumberland about the extent of trust in the nuclear regulators to regulate a GDF. 69% of respondents said they “trust [regulators] a lot” or “trust a fair amount”. Yonder noted that “trust in the Environment Agency and ONR was high – particularly in Copeland”.

Theddlethorpe GDF Community Partnership

We were invited to attend the Theddlethorpe GDF Community Partnership in June 2024 to speak about our role in regulating geological disposal. The session was postponed until September to comply with pre-election period guidance. On 19 September 2024, we joined the ‘meet and greet’, presented to the first meeting in public and answered questions from the audience.

Following the meeting, we highlighted to the Theddlethorpe Community Partnership that local community understanding and awareness could benefit from including more information about our regulation in the community partnership’s newsletters and ebulletins.

We did not attend any further meetings of the partnership.

Wider stakeholder engagement and consultation on geological disposal

In May and November 2024, the Environment Agency held its bi-annual ‘meet the regulator’ engagement forum for stakeholders in Cumberland, which provides an opportunity for discussion and questions about geological disposal. In May, we provided an update on our geological disposal work, including information about the upcoming GRA/staged regulation consultation. In November, we highlighted our guidance consultation and answered questions on geological disposal. The meetings were attended by members of the Copeland GDF Community Partnerships.

ONR’s Non-Governmental Organisation (NGO) Forum meets twice a year. The meetings provide an opportunity to discuss and engage with members of the NGO community on a range of issues, including geological disposal. During the reporting period, the forum met in April and November 2024. Minutes from the meeting are available on ONR’s website.

Both the Environment Agency and ONR have responded to several enquiries from the public and NGOs about how we would regulate geological disposal.

Both regulators also promoted our 2023 to 2024 GDF report widely to stakeholders.

The Environment Agency provided information about regulating geological disposal to MPs in Cumberland, Westmorland and Lincolnshire through established local routes and Area Director updates.

Both regulators attended several meetings of the West Cumbria Sites Stakeholder Group during the year, including 2 NWS themed meetings in August 2024 and February 2025, where updates on geological disposal were provided.

We met with the Committee on Radioactive Waste Management (CoRWM) twice during 2024 to 2025. We discussed CoRWM’s developing position on an underground research laboratory (URL), which we expect to be published later in 2025, and the links between our staged regulation of a GDF and the National Policy Statement for geological disposal. We also discussed CoRWM’s forward workplan and its position on interim storage for HAW.

Working with NWS

The Environment Agency and ONR meet regularly with NWS’s community engagement and communications team. These meetings enable NWS to share its plans for community engagement and help us support community discussions.

We work with NWS to consider how best to share information about regulation with community partnerships and any future working groups that may emerge. We also receive updates from NWS on its corporate communications on geological disposal, national stakeholder engagement, and work with CoRWM.

Summary

The Environment Agency and ONR engaged with NWS during 2024 to 2025 to provide pre-application advice and scrutiny of its developing GDF Programme, as well as to prepare for future regulation and to support the siting process.

NWS kept us informed on developments to the GDF Programme throughout the year. In summer 2024, NWS told us of a delay in planned submission dates for its intrusive investigation permit and DCO applications. We currently plan to receive the first permit application in about 2028. However, we recognise that there is significant uncertainty relating to the potential impacts of the 2025 government spending review on the GDF Programme and the currently limited portfolio of potential host communities.

NWS formally became a single legal entity in April 2024, created by the merger of the Low Level Waste Repository Ltd and Radioactive Waste Management Ltd businesses. It is developing harmonised management arrangements for the business. The approach to organisational change and arrangements for intelligent customer and contract management will be a priority for our readiness evaluations as the GDF Programme moves towards its application for the first permit.

The Environment Agency engaged with NWS during 2024 to 2025 to make sure that it has a good understanding of our permit requirements. We confirmed our position on activities that fall within the scope of intrusive investigations for a GDF. We also drafted a permit template for the intrusive investigations and issued it to NWS for review and comment.

The Environment Agency gained a better understanding of NWS’s descriptive models of the Copeland and Theddlethorpe areas, which it will use to justify any proposals for intrusive investigations. We assessed the site descriptive models to determine progress towards meeting our requirements for the intrusive investigation permit application, concluding that NWS has made considerable progress using good science. We also gained understanding of its developing site characterisation plans and delivery strategy.

We provided advice to NWS on its developing design strategy and its strategy for delivering environmental, safety, security and safeguards safety cases for the GDF. We have also provided advice on its strategy for demonstrating optimisation of radiological protection and the use of BAT to make sure that they are consistent with regulatory requirements.

We continue to engage with NWS to make sure that the disposability advice it provides to waste producers is compatible with the current geological disposal concept and designs. We inspected NWS’s progress against 2 outstanding Regulatory Issues on this topic. Following the inspection, we closed both Regulatory Issues and raised a new one on keeping disposability assessments and GDF developments current and consistent.

We restarted our engagement on NWS’s GDF research, development and demonstration (RD&D) programme, including its generic approach to developing its research and how it will move to site-specific research plans. We identified a number of research areas on which we wish to be informed of progress and received an update on NWS’s waste barriers and pathways research.

The Environment Agency made significant progress in our preparations for regulating a GDF. We finalised the consultation versions of the UK environment agencies updated guidance on the requirements for authorisation of disposal facilities for solid radioactive waste (the GRA) and our guidance for staged regulation of a GDF. Both documents were consulted on in 2024 to 2025. We are reviewing the consultation responses and aim to publish final versions in 2026.

Recognising that the regulation of a GDF is a first-of-a-kind activity in the UK, we continue to build our capability to ensure that we can regulate a GDF over the coming decades. We have brought staff into the programme and developed capability through a variety of means, including training courses and international engagement.

Regulators have no role in the siting process for a GDF. However, we have participated in community partnership events when invited and remain committed to supporting the community partnership areas to explain our role in geological disposal and our regulatory processes. We also hold our own stakeholder engagement events throughout the year at which geological disposal is discussed.

NWS was still assessing the implications of the government spending review on the GDF Programme at the time of publication of this report. We observe that many activities in the GDF Programme, in particular developing the science and technology that will underpin the design and safety cases, have long lead times. Delays in programme activities in the short term will have significant implications on programme timings in later stages, and will likely cause the expected first waste emplacement date to be delayed further.

ONR believes that a successful UK nuclear industry is an industry that deals with its waste in an appropriate, timely manner. Without adequate funding of critical enabling activities such as the GDF, this will not be achieved, with continued deferrals and degrading assets likely, alongside the associated increases in risks to safety and security. As part of our submission to the Nuclear Regulatory Taskforce, commissioned by DESNZ, the Environment Agency advised that the delivery of a GDF, along with fit-for-purpose and sustainable options for managing lower activity waste, are considered as part of the energy infrastructure priority, alongside the new build programme and the development of new technologies.

Annex A: List of Regulatory Issues and Observations

Regulatory Issue	Title	Status
GDF_RI_001	Leadership and governance	Closed
GDF_RI_002	Organisational capability	Closed
GDF_RI_003	Control and assurance	Closed
GDF_RI_004	Organisational learning	Closed
GDF_RI_005	Assessment of innovative packaging proposals	Closed
GDF_RI_006	Resolution of periodic review findings	Closed
GDF_RI_007	Assurance of packaging assessments and advice	Closed
GDF_RI_008	Board governance of important areas of risk/performance	Closed
GDF_RI_009	Corporate Health, Safety, Security, Environment and Quality (HSSEQ) structure	Closed
GDF_RI_010	Disposability assessments and endorsements sensitive to changes	Closed
GDF_RI_011	Waste package records	Closed
GDF_RI_012	Workforce capability plan	Closed
GDF_RI_013	Characterisation and assessment of the non-radioactive component of waste in the inventory for disposal	Open
GDF_RI_014	Operational environmental safety assessment	Open
GDF_RI_015	Approach to fire safety assessment	Open
GDF_RI_016	Keeping disposability assessments and GDF development current and consistent	Open

Regulatory Observation	Title	Status
GDF_RO_001	Protection against non-radiological hazards	Closed
GDF_RO_002	Optimisation	Closed
GDF_RO_003	Lessons from the Fukushima disaster	Closed
GDF_RO_004	Defining waste package fissile limits for disposal	Closed
GDF_RO_005	Lessons from the Waste Isolation Pilot Plant (WIPP)  incident	Closed
GDF_RO_006	Building confidence in data and modelling	Closed
GDF_RO_007	Auditable evidence in support of an environmental safety case (ESC)	Closed
GDF_RO_008	Defining waste package fissile levels	Closed

References

1. Environment Agency And Northern Ireland Environment Agency, February 2009. Geological disposal facilities on land for solid radioactive wastes: Guidance on requirements for authorisation. [Accessed 5 September 2025] ↩

2. ONR, March 2023. Technical Assessment Guide. Geological disposal ns-tast-gd-101.docx. [Accessed 5 September 2025] ↩

3. ONR, January 2020. Safety Assessment Principles for Nuclear Facilities ONR CM9 Ref 2019/367414. 2014 Edition, Revision 1. [Accessed 5 September 2025] ↩

4. ONR, March 2022. Security Assessment Principles for the Civil Nuclear Industry. 2022 issue, version 1. [Accessed 5 September 2025] ↩

5. Department for Energy Security and Net Zero, Scottish Government, Welsh Government and Northern Ireland Department of Agriculture, Environment and Rural Affairs (May 2024) UK policy framework for managing radioactive substances and nuclear decommissioning. [Accessed 5 September 2025] ↩

6. Environment Agency and ONR, October 2024. Regulatory scrutiny and engagement for geological disposal: annual report 2023 to 2024. [Accessed 5 September 2025] ↩