Current Arrangements and Requirements for the Conditioning, Packaging and Storage of Intermediate Level Radioactive Waste: Joint RWMAC/NuSAC Report

EXECUTIVE SUMMARY

This report sets out the findings of a 2001-2 joint study by the Radioactive Waste Management Advisory Committee (RWMAC) and the Nuclear Safety Advisory Committee (NuSAC) of current arrangements and requirements for the conditioning, packaging and storage of intermediate level radioactive waste (ILW) within the United Kingdom (UK). The main conclusions and recommendations may be summarised as follows.

The current state of ILW

1. ILW covers a wide range of waste streams, including materials irradiated in nuclear reactors or used in the reprocessing of spent fuel. As of April 1998 (the time of the most recent official figures), only a small proportion - 12 per cent - of existing ILW had been conditioned: that is put into a form suitable for long-term storage and/or disposal. Most of the remainder, which has arisen from nuclear industry operations over many decades, is stored in untreated form on licensed nuclear sites.

2. There are various reasons for the current situation. Government policy prior to 1995 was that ILW should remain untreated for as long as it was safe to do so. This reflected a concern that treatment might foreclose disposal options. The policy also meant that expenditure on new ILW conditioning and storage facilities could be deferred. Although the 1995 White Paper, Cm 2919, relaxed the presumption against early treatment in circumstances where safety or economic benefits could be achieved, it did not provide a major impetus for conditioning programmes.

3. But circumstances have changed. The collapse of the United Kingdom Nirex Ltd (hereafter Nirex) ILW underground repository programme in 1997 dramatically lengthened the times over which interim storage of ILW could be anticipated. This reinforced the concerns of the Nuclear Installations Inspectorate (NII) about the storage conditions of some ILW, and led to increasing emphasis on the need for potentially mobile wastes to be conditioned.

4. Particular concern has focused on "historic" wastes. These may be poorly characterised, physically and chemically degraded, and held in old facilities subject to deterioration. Attention has also been drawn to other "challenging" wastes, including material where effective immobilisation is difficult, and materials with inherent hazards (such as reactive metals and high fissile content).

5. Against this background, RWMAC/NuSAC consider that it is now unsatisfactory that only a small proportion of ILW has been treated.

Recommendation 1: Waste producers should have clearly articulated strategies and plans for the conditioning, packaging and storage of ILW. Clear targets and objectives should be set for such work, against which progress should be monitored and openly reported.

Recommendation 2. Waste producers, in conjunction with Nirex and the regulators, should provide the resources necessary to deal with challenging ILW, with emphasis on historic wastes.

Need for review and development of policy

6. RWMAC/NuSAC are concerned about the currency and sufficiency of policy set out in the 1995 White Paper, Cm 2919. The Committees believe that Cm 2919's uncertain status - where some parts may be extant and some superseded - is unhelpful and unsatisfactory. In particular, there is a need for a clear and updated statement of Government policy for the interim management of ILW (as pertaining to the period prior to implementation of long-term management options). The need for policy clarity is further underlined by the Government's decision to set up a Liabilities Management Authority (LMA), which will be responsible for the management of public sector civil nuclear liabilities.

7. Against this background, RWMAC/NuSAC are concerned that national policy regarding the conditioning, packaging and storage of ILW is effectively being set by default - and in a potentially fragmented fashion - by the waste producers, the regulators and Nirex. While the views of such bodies are clearly important, national policy needs to be decided and clearly stated by Government.

8. Government policy on the management of radioactive wastes must cover all time periods. The Government consultation paper, "Managing Radioactive Waste Safely" (MRWS), focuses primarily on the processes that might be used to formulate policy on the long-term management of solid radioactive wastes. Although some statements on shorter-term issues are contained in MRWS, it does not encompass the full range of issues that must be addressed in developing policy on the conditioning, packaging and storage of ILW.

Recommendation 3: Although a full statement of Government radioactive waste management policy will not be possible until the programme of consultation arising from MRWS is complete, the Government should clarify which parts of Cm 2919 are extant and which are not.

Recommendation 4: Pending any policy decision on long-term radioactive waste management, the Government should take the earliest possible opportunity to develop and state its policy for the conditioning, packaging and storage of ILW.

Towards passive safe storage

9. RWMAC/NuSAC support the view that, so far as is reasonably practicable, ILW should be stored according to the principles of passive safety set out in NII guidance to its inspectors. These principles describe the attributes of passive safety, including that the radioactivity be immobile and the waste form and container be chemically and physically stable, so that the need for safety systems, maintenance, monitoring and human intervention is minimised. The Committees commend the NII's principles, and concur with the regulator's view that licensees should aim to apply them within a framework of reasonable practicability and cost-effectiveness. We also wish to highlight that passive safety cannot be regarded as an absolute, not least because judgement will always be required in implementation of the "passivity" principles.

10. As ILW conditioning and packaging programmes are developed, there are likely to be tensions around passive safe storage and interpretations of reasonable practicability and cost-effectiveness. Within the framework established by NII guidance, RWMAC/NuSAC consider it legitimate for NII to scrutinise and, where necessary, robustly challenge waste producer proposals, as long as conclusions are reached on the basis of transparent, consistent, case by case judgements that take proper account of all relevant factors.

Recommendation 5: Government policy on passively safe storage should be clarified. It should endorse the view that, so far as is reasonably practicable, ILW should be stored according to the principles of passive safety (as set out in NII guidance to its inspectors).

11. Given the extended periods of storage now likely, and regulatory concerns about the storage conditions of some ILW waste streams, RWMAC/NuSAC also consider that NII emphasis on the implementation of programmes to achieve passively safe storage as soon as reasonably practicable is appropriate. This is as long as due recognition is given to the "disposability" of conditioned waste forms (see below). RWMAC/NuSAC also expect proper regard to be paid to the safety-related factors that should influence the timing of specific conditioning programmes.

Recommendation 6: Government policy should assert a presumption in favour of conditioning as soon as reasonably practicable, provided due account is taken of the safety of existing storage arrangements and the "disposability" of the conditioned waste form.

12. There is also a need for Government to clarify its expectation of the timescales for interim storage. This would encourage a greater focus on the standards required for the provision of packages and stores, and help inform local development control and planning decisions. The main waste producers and regulators all broadly accept that it would be prudent to plan for a period of interim storage of the order 100 to 150 years.

Recommendation 7: The Government should state its expectation of prudent lifetime objectives for the packaging and interim storage of ILW.

Disposability and the Letter of Comfort system

13. RWMAC/NuSAC consider there is a continuing need for a system that seeks to ensure the disposability of conditioned waste forms, so that disposal options are not foreclosed for future generations. Disposability in this context is defined as the likelihood that a package of conditioned ILW will be acceptable for disposal in a purpose-designed facility. The continuing need for such a system has been brought into sharp focus by NII's emphasis on the early conditioning of wastes.

14. Nirex currently provides a system of endorsement that packaged wastes will meet future management requirements, including potential disposal. This is known as the Letter of Comfort (LoC) system, which is operated in three stages (conceptual, interim and final). The system also entails the provision of packaging advice based on standards and performance specifications developed by the company. The packaging advice is currently linked to Nirex's Phased Disposal Concept.

Recommendation 8: Government policy should recognise the important role that Nirex expertise and advice plays in safeguarding the disposability of conditioned waste forms.

15. RWMAC/NuSAC recognise the importance of operating the LoC system to well founded programmes, with a clear commitment to early discussions about specific conditioning programmes, involving waste producers, the regulatory bodies and Nirex (or successor organisation). Such an approach should contribute to the resolution of technical problems.

Recommendation 9: Government policy should emphasise the importance of operating the LoC system to well founded programmes, with a clear commitment to early discussions between key stakeholders.

16. The early and sustained involvement of Nirex (or successor organisation) is important for the timely provision of packaging advice and enabling long-term disposability requirements to be properly considered. RWMAC/NuSAC consider that this could be achieved by formally stating that such involvement is a requirement of Government policy. This approach would avoid the need for legislation to provide Nirex with the status of statutory consultee, which the company suggested during the course of this study. Legislative change would entail various difficulties given the present ownership of Nirex and uncertainty about the company's future. The required statement of Government policy should highlight the importance of the advisory role currently fulfilled by Nirex.

Recommendation 10: Government should state that the early and sustained involvement of Nirex (or successor organisation) in discussions about proposals for specific conditioning programmes is a requirement of policy.

17. RWMAC/NuSAC also recognise that the disposability of waste forms is central to the environment agencies' responsibilities and, subsequently, that there is a case for enabling the agencies to provide additional "regulatory assurance" that this will usually be achieved. However, the Committees do not favour the Environment Agency (EA) suggestion of a new statutory power over the storage of radioactive wastes because of the difficulties that are likely to arise from dual regulation. An alternative approach might be to make each of the three stages of LoC subject to endorsement by the appropriate environment agency. This could be stated as an expectation of policy, and be achieved by formal administrative agreement between NII and the appropriate agency. Another approach might be to develop a new statutory role for the agencies based on the issue by them of a "certificate of disposability".

Recommendation 11: The EA proposal for a new statutory power over the storage of radioactive wastes should not be adopted. However, alternative ways of enabling the environment agencies to provide additional "regulatory assurance" of the disposability of waste forms should be subject to early appraisal by Government. Whichever approach is adopted, policy should recognise the potential need for interim packaging arrangements (see recommendation 14), and for means of dispute resolution (see recommendation 18).

18. Nirex is currently assessing the robustness of its packaging advice to a range of long-term management options. RWMAC/NuSAC consider it important that Nirex publish its assessments at an early date so that claims for the wider applicability of its packaging advice, and the implications for long-term policy, can be reviewed.

Recommendation 12: Nirex should publish, at an early date, its assessments of the robustness of its packaging advice to a range of long-term ILW management options. These assessments should be fed into the current policy review of these options.

19. If the current policy review does not result in the adoption of a policy of deep underground disposal, the linkage between the LoC system and Nirex's Phased Disposal Concept will be become increasingly questionable. In such circumstances, RWMAC/NuSAC recommend that the form, institutional location and presentation of the LoC system be made subject to fundamental review. The purpose would be to develop an appropriate system for safeguarding the disposability of waste forms, so that disposal options are not foreclosed for future generations. There will also be a need to ensure that the expertise currently available within Nirex is not lost.

Recommendation 13: If the current policy review of long-term management options does not result in the adoption of a policy of deep underground disposal, the form, institutional location and presentation of the LoC system should be made subject to fundamental review.

Interim packaging arrangements

20. BNFL's proposed "Interim Safe Storage" (ISS) strategy for the Sellafield site is a significant development in the field of ILW management and requires careful consideration by national and local stakeholders. In view of safety concerns about the storage of historic wastes on the Sellafield site, RWMAC/NuSAC acknowledge that in certain circumstances it may be necessary to adopt interim packaging arrangements for specific waste streams. In this context, an interim packaging arrangement means that a packaged waste has not secured a LoC. The Committees consider that such "interim" arrangements require convincing and transparent case-by-case justification. In addition, where such arrangements can be justified, we strongly favour approaches which facilitate final treatment at a later date, rather than requiring complete re-working to meet future needs.

Recommendation 14: Government policy should acknowledge the potential need for interim packaging arrangements, where a packaged waste would not be covered by a Nirex LoC. However, policy should state an expectation that such an approach would only be adopted in openly declared and justified cases, and with the agreement of NII and appropriate environment agency (see recommendations 11 and 18). In such cases, the policy expectation should be that the waste would be packaged in a way that facilitates final treatment at a later date.

Regulation of radioactive discharges

21. RWMAC/NuSAC are concerned that the disagreement between BNFL and EA about the implications for the treatment of historic wastes arising from the latter's proposals for the regulation of Sellafield discharges remains unresolved. This is an important issue because the investigation, characterisation and retrieval of historic ILW could in principle give rise to unexpected discharges beyond that which would be allowed in the discharge authorisation proposed by EA.

Recommendation 15: Government should review the implications of proposals for the regulation of Sellafield discharges for the treatment of historic ILW. This should be done in conjunction with BNFL and the regulators, so that the matter can be resolved in an appropriate way prior to finalisation of the UK Discharge Strategy and Statutory Guidance to the environment agencies.

Tensions at the regulatory interface

22. There have been regulatory tensions between NII and the environment agencies that can impact on plans for the conditioning, packaging and storage of ILW. Against this background, RWMAC/NuSAC welcome the strenuous efforts that the regulators are currently making to overcome such difficulties. The Committees consider that the extent to which these initiatives deliver improvements should be carefully monitored and assessed by the regulators in conjunction with other key stakeholders. Such monitoring and assessment needs to be ongoing.

Recommendation 16: Efforts being made to resolve tensions at NII and environment agency regulatory interfaces should be carefully monitored and assessed by the regulators in conjunction with other key stakeholders to ensure their effectiveness.

The LMA and the management of ILW

23. Ideally, the proposed LMA should be given a remit based on a full and clear statement of Government radioactive waste management policy. RWMAC/NuSAC are concerned that this will not be possible given current policy deficits and the ongoing review of long-term management options. As stated above, in these circumstances, Government should take the earliest possible opportunity to develop and state its policy for the conditioning, packaging and storage of ILW. This policy should cover passively safe storage, the disposability of conditioned ILW, the role of interim packaging arrangements, and the impact of proposals for the regulation of radioactive discharges.

24. The notion of "common purpose" - based on commonality of interests in wanting to see liabilities discharged safely and effectively - fits well with the conclusions in this report about the need for early involvement of key stakeholders - notably the waste producers, the regulation bodies and Nirex - in the formulation of strategic plans and programmes for the management of ILW. RWMAC/NuSAC welcome statements from the regulators, which provide an indication of their commitment to making a "common purpose" approach work in practice.

Recommendation 17: Government policy should encourage a "common purpose" approach between the waste producers, the regulatory bodies and Nirex, to the development of strategies and programmes for the conditioning, packaging and storage of ILW.

25. RWMAC/NuSAC are aware of a range of disagreements and disputes that arise in relation to the management of ILW. It is our expectation that many such difficulties could be more easily resolved if the key stakeholders were operating within a clear and sufficient policy context, whilst embracing a "common purpose" approach. Nonetheless, the Committees consider that there may still be a requirement for clearly defined channels, presumably at senior management levels, for resolving disputes. These channels should aim to eliminate the kinds of unacceptable delay to some ILW treatment programmes that have been experienced in the past.

Recommendation 18: The waste producers, regulators and Nirex should ensure the availability of channels for resolving disputes that have potential to delay the conditioning and packaging of ILW.

26. RWMAC/NuSAC welcome attempts to develop hazard reduction or safety indexes, which primarily seek to provide an easily understandable means of assessing and demonstrating progress towards the achievement of passive safe storage. Provision of clear information to the public concerning such progress should be seen to be a key objective. Proposals for such indexes should therefore be exposed to wide-ranging peer review and stakeholder comment prior to any formal adoption and use. Such steps are essential if the indexes are to secure "sign-on" from Government, the regulators and other key stakeholders, such as the local authorities in the areas containing major British Nuclear Fuels plc (BNFL) and United Kingdom Atomic Energy Authority (UKAEA) sites.

Recommendation 19: Provision of clear information to the public about progress towards the achievement of passive safe storage should be seen to be a key objective of proposals for hazard reduction or safety indexes. Proposals for such indexes should therefore be exposed to wide-ranging peer review and stakeholder comment prior to any formal adoption and use. Such steps are essential if the indexes are to secure "sign-on" from Government, the regulators and other key stakeholders.