Guidance

[Withdrawn] Decommissioning: generic developed principles

Updated 2 May 2024

Applies to England

This guidance was withdrawn on 2 May 2024.

The Environment Agency has withdrawn the generic developed principles for decommissioning - they no longer form part of their guidance. They have replaced these principles with guidance for nuclear sites undergoing decommissioning.

In this document we describe the principles that we will use to assess operators’ proposals for decommissioning their plants – so as to minimise the amount of radioactive waste to be disposed of. We would expect an operator to have decommissioning strategy and plan to show how he will achieve this aim.

The decommissioning developed principles (DEDPs) relate to all sites and facilities where radioactive substances have been used and where radioactive wastes will arise during demolition or redevelopment. They do not apply to disposal facilities for solid radioactive wastes that are being ‘closed’ (where the wastes are to remain in place), rather than ‘decommissioned’ (where the wastes are to be removed).

The principles are derived from national policy and international guidance for decommissioning of nuclear facilities. They should be applied in a way that is proportionate to the risks and hazards posed by the sites and facilities.

For example, the decommissioning strategy for a nuclear site (DEDP1 ) is likely to be complex and should be developed with appropriate stakeholder involvement. The strategy for a small non-nuclear facility can be simple and be prepared by the operator alone.

The principles related to our role in regulating radioactive wastes produced during decommissioning are in the document Radioactive Substances Management : generic developed principles.

DEDP1 – decommissioning strategy

Each site should have a decommissioning strategy that is updated and refined at appropriate intervals.

Considerations

The decommissioning strategy should be integrated with other relevant site strategies (for example, those for waste management and for the management of contaminated land).

Stakeholder views should be taken into account in developing, updating and refining the decommissioning strategy.

Strategy development should be informed by an environmental assessment and optimisation process in which alternatives are systematically evaluated and compared in terms of their impacts on worker safety, people and the environment, their financial costs and other factors.

Alternative strategies should differ in, amongst other aspects, the time at which decommissioning will take place. The preference is for prompt decommissioning but decisions should be made on a case-by-case basis, taking into account all the relevant factors.

The strategy should include timescales for the future operation, shutdown and decommissioning of all the facilities on a site, including proposed new facilities, and timescales for the remediation of contaminated land.

The strategy should describe the proposed end-state for the site and show how stakeholders’ views will be taken into account in reviewing it.

The strategy should incorporate the use of the best available techniques to minimise the generation of radioactive and non-radioactive wastes, particularly by re-using equipment, facilities and buildings, and by re-using or recycling materials.

The strategy should include a demonstration that appropriate financial arrangements have been made for decommissioning and restoration of the site.

It is acceptable to establish one, over-arching strategy for a group of similar sites, provided that it is clear how that strategy will be implemented at each separate site.

The decommissioning strategy should be updated and refined during the operating life of the site and in the initial stage of decommissioning. Updates should take into account policy, regulatory and technological changes. Refinements should add more detail as the time for decommissioning approaches.

DEDP2 – decommissioning plan

There should be a decommissioning plan for each facility and this should be updated and refined throughout its operating life and during decommissioning.

Considerations

Initial decommissioning plans should be prepared during the design and construction of new facilities.

Decommissioning plans for facilities should be consistent with the decommissioning strategy for the site.

Plans should include decommissioning programmes for each facility, with timings for key actions.

Decommissioning plans should describe the end-state for each facility, and any interim states.

Estimates of the types and quantities of wastes that will be generated during decommissioning should be included in plans, with indications of when the wastes will arise.

Plans should specify the means of managing facility decommissioning wastes. These means should be consistent with the waste management strategy for the site.

Plans should specify the means of managing contaminated land associated with each facility. These means should be consistent with the contaminated land strategy and the integrated waste strategy for the site.

Decommissioning plans should include a programme for further characterisation of irradiated and contaminated structures, plant and equipment in each facility, and further characterisation of any contaminated land and groundwater.

Plans should include activities to make facilities passively safe before any period of care and maintenance (for example, by removing any radioactive wastes that are not in a form suitable for passively safe storage, by removing or immobilising radioactive contamination).

If there is no decommissioning plan for an existing facility, one should be prepared as soon as is practicable.

Updates of facility decommissioning plans should take into account changes to the site decommissioning strategy and policy, regulatory and technological changes. Plans should be made more detailed as the time for decommissioning approaches.

DEDP3 – considering decommissioning during design and operation

Facilities should be designed, built and operated using the best available techniques to minimise the impacts on people and the environment of decommissioning operations and the management of decommissioning wastes.

Considerations

Designs should include features to prevent radioactive contamination and limit its spread.

Designs, including choices of materials, should minimise activation of structures, plant and equipment.

Designs should facilitate the segregation of radioactive and non-radioactive wastes during decommissioning.

The implications for decommissioning should be considered throughout the operating life of a facility, especially when modifications to plant, equipment or methods of operating these are proposed.

All other appropriate steps should be taken during design and operation to maximise the potential re-usability of plant, equipment and materials when the facility reaches the end of its operating life, and to minimise the quantities of radioactive wastes produced when it is decommissioned.

DEDP4 – discharges during decommissioning

Aerial or liquid radioactive discharges to the environment during decommissioning should be kept to the minimum consistent with the decommissioning strategy for the site.

Considerations

For every major decommissioning operation that would lead to radioactive discharges the best available techniques should be used to prevent and where that is not practicable minimise these discharges.

Increases in discharge levels should only be permitted when they are essential to implementation of the site decommissioning strategy. Both the size and duration of increases in discharges should be minimised. In general, increases should take place within a framework of progressive reductions in discharges as decommissioning of the site proceeds.

DEDP5 – legacy wastes

Decommissioning strategies and plans should provide for the timely characterisation, retrieval, conditioning and packaging of legacy radioactive wastes.

Considerations

Prior to retrieval of legacy wastes, they should be characterised in enough detail to allow the best available techniques for retrieving, conditioning and packaging them to be defined. More detailed characterisation should be performed after retrieval, if necessary.

Legacy wastes should be conditioned and packaged using the best available techniques to meet requirements for interim storage and for eventual disposal.