Guidance

Radiological protection of people and the environment: generic developed principles

Published 1 December 2021

Applies to England

In this document we describe the basic principles which underpin how we regulate businesses to protect people and the environment against radioactivity – the radiological protection developed principles (RPDPs).

There are 3 principles:

1. Justification
2. Optimisation
3. Compliance with limits

The first ensures that where an activity (or ‘practice’) involves exposure to radiation there is an overall net benefit from that activity. The government decides which practices are allowed (or ‘justified’), so setting out the activities or practices that radioactive substances can be used for.

Optimisation means users of radioactive substances must do their best to minimise radiation exposure, for example by minimising the amount of radioactive waste discharged – we describe our principles for how an operator can achieve this in the document Radioactive substances management: generic developed principles.

Lastly, the radiation dose to people arising from their exposure to radioactive substances or wastes must be less than the values set out in law.

The following points should be noted in connection with the radiological protection principles.

The radiological protection principle of justification is covered in the topic areas to which it is most relevant in radioactive substances regulation (see RSMDP2 in the document Radioactive substances management: generic developed principles and CLDP3 in the document Contaminated land and groundwater: generic developed principles).

No references to the International Commission on Radiological Protection (ICRP) are included because this could imply direct acceptance of ICRP recommendations, without scrutiny by Public Health England, which is the statutory adviser to the UK government on radiological protection standards.

Specific principles for facilities for the disposal of solid radioactive wastes are given in the Guidance on Requirements for Authorisation (GRA) document Near-surface disposal facilities on land for solid radioactive wastes.

RPDP1 – optimisation of protection

All exposures to ionising radiation of any member of the public and of the population as a whole shall be kept as low as reasonably achievable (ALARA), economic and social factors being taken into account.

Considerations

The ALARA principle should be applied to all aspects of the management of radioactive substances and wastes, including their disposal. This includes the management of radioactively contaminated land (see Contaminated land and groundwater: generic developed principles).

In the case of disposals of radioactive wastes, compliance with the ALARA principle should be achieved by applying ‘best available techniques’ (BAT). The scope of BAT assessments should be such that aspects relevant to ALARA are included.

The requirement to apply the ALARA principle in all our RSR activities stems from the 2013 EU Directive on laying down basic safety standards for protection against the dangers arising from exposure to ionising radiation (known as the Basic Safety Standards Directive or BSSD).

RPDP2 – dose limits and constraints

Radiation doses to individual people shall be below the relevant dose limits and in general should be below the relevant constraints.

Considerations

No option for the management of radioactive substances or radioactive wastes shall be pursued if, in normal operation, it would lead to doses above the legal limits. These dose limits are specified in the Ionising Radiations Regulations 2017, to which all the organisations that we regulate as radioactive substances activities are subject, and are referred to in the Regulations. They are given here for completeness.

The dose limits for members of the public are: 1 mSv per year effective dose, 15 mSv per year dose to the lens of the eye and 50 mSv per year dose to the skin. The limits do not apply to doses in the event of nuclear accidents or radiological emergencies, to natural background radiation or to medical irradiation.

The dose limits for workers over 18 years old are: 20 mSv per year effective dose, 20 mSv per year dose to the lens of the eye and 500 mSv per year dose to the skin. (There are lower limits for trainees and for pregnant women, see the Ionising Radiations Regulations 2017 and their Approved Code of Practice for details.)

Two dose constraints for members of the public should be used at the planning stage in radioactive discharge regulation. These constraints are given in the BSSD and are:

• 0.3 mSv per year for proposed discharges and direct radiation from any new source
• 0.5 mSv per year for discharges from any single site

Unless there are exceptional circumstances that make compliance with these constraints impracticable, no option for the management of radioactive substances or radioactive wastes should be pursued if, in normal operation, its associated discharges would lead to doses above them.

RPDP3 – protection of non-human species

Non-human species should be adequately protected from exposure to ionising radiation.

Considerations

The objective generally should be to protect populations of species of flora and fauna, rather than to protect every individual organism except where specified by legislation.

The approach used to assess the adequacy of protection of non-human species should be that described in R&D Publication 128 and R&D Technical Report P3-101/SP1a (Copplestone et al, 2001 and 2003).

Key species that need protection in appropriate habitats and habitat features should be identified. Dose rates to these species should be estimated using information in the reports and compared to a guideline value of dose rate below which there appears to be no harm to the species at the population level. Our current guideline value is 40 microGray per hour.

Note that the requirement for ‘optimisation’ (keeping risks ALARA) applies only to radiological risks to people. Other living organisms must be protected from radiological hazards but there is no optimisation requirement.

RPDP4 – prospective dose assessments for radioactive discharges into the environment

Assessments of potential doses to people and to non-human species should be made prior to granting any new or revised permit for the discharge of radioactive wastes into the environment.

Considerations

Applicants for new or revised permits should carry out prospective dose assessments and submit these with their applications. The assessments should be for discharges at expected levels and at requested limits.

In general, the assessments should include doses to people and dose rates to non-human species. The requirement to estimate dose rates to non-human species may be relaxed if it is clear that there is no possibility of significant impact on such species.

Where necessary, we will carry out our own prospective dose assessment for discharges at our proposed limits.

Assessments of doses to the public should be consistent with guidance given in Assessment of Prospective Public Doses from Authorised Discharges and with guidance produced by the National Dose Assessment Working Group.

Doses to individuals (members of critical groups) should be estimated and compared to the appropriate limits and constraints.

Where appropriate, collective doses should be estimated for use in BAT assessments and ALARA studies. Collective doses should be broken down into their components in time, space and, where appropriate, individual dose levels.

Dose rates to non-human species should be estimated using the approach in Copplestone et al, 2001 and 2003.

The level of detail in assessments should be commensurate with the magnitude of anticipated radiological impacts.

Alternative assessment approaches to those above may be proposed where appropriate and should be considered.

All assessments should be based on appropriate science and data. Realistic assumptions should be used in assessments unless screening tools are employed.

In due course, the results of prospective dose assessments should be checked against the results of retrospective dose assessments based on monitoring data where these are available see RSMDP13 in the document Radioactive substances management: generic developed principles.