RWMAC's Annual Report for 2000-2001

Chapter 5

Management of UK Low Level Solid Radioactive Waste

Background

5.1 Chapter 3 set out RWMAC's views, contained in its advice for Ministers ¹, on the methods and techniques available to support public consultation on the options for long-term management of solid radioactive wastes. The advice adopts a generic approach, in the sense that references to individual waste categories are given mainly for the purposes of illustration. RWMAC believes that the public's views on the various policy options for managing radioactive waste need to be sought in a holistic way, although the implementation of policy, once formulated, will need to take detailed account of individual waste categories, since the precise type of management facilities required will be different in each case.

5.2 The Committee's perception is that, traditionally, the focus of public thinking on long-term management issues for solid wastes has been on ILW and HLW, particularly the former since it was disposal of ILW, together with a small part of the LLW inventory (that which, because of its relatively high alpha-emitting content, is not suitable for disposal to Drigg), that was covered in the repository development remit given to Nirex. However, the Committee has become aware of several issues relating to LLW that indicate that it too should be included in the review of radioactive waste management policy. This chapter describes the present position at the two UK LLW disposal sites and some of the policy issues that have been identified.

Drigg and Dounreay

5.3 Two facilities exist for the specific purpose of the disposal of UK LLW - Drigg (operated by BNFL), which accepts wastes from a wide variety of sources, and the disposal area at Dounreay, the LLW "pits", (operated by UKAEA), which has been used for local arisings. RWMAC visited Dounreay and Drigg respectively in September and November 2000.

5.4 At Dounreay, the last of the pits in the disposal area is virtually full and waste is no longer being routinely consigned to it. Solid waste continues to arise at Dounreay, however, and will continue to do so at an increasing rate as decommissioning progresses. The Dounreay Site Restoration Plan (DSRP) ² describes a "reference strategy" for the future management of LLW from the site. This envisages interim storage on site pending the development of plans to provide a long-term management solution that will accommodate all future solid LLW arisings from Dounreay. The appropriate solution is to be determined by carrying out a BPEO study. In its advice to Ministers following consideration of the DSRP ³ (see also Chapter 7), RWMAC noted the extent to which decommissioning progress at Dounreay depends on there being in place adequate arrangements for the management of LLW, and recorded its concern about the uncertainties surrounding UKAEA's plans in this regard.

5.5 The Drigg site is owned and operated by BNFL, but accepts waste from a wide variety of sources throughout the UK, including hospitals, research establishments and industrial concerns, as well as nuclear sites. At the site there is a "consented area", approved by the local planning authority for development, of about one third of the total land in BNFL ownership, that may be used for LLW disposal.

5.6 The disposal of LLW at Drigg is controlled under the terms of an authorisation granted by EA under RSA93. During its site visit, RWMAC was given details of the work being carried out in preparation for the review of the authorisation, which is due to start in 2003. The work includes the development of an up-to-date Post Closure Safety Case (PCSC) for the site together with an Operational Environmental Safety Case (OESC) covering the period up to the site's closure. The need for such documentation was introduced when EA varied the current Drigg authorisation in February 2000.

5.7 The new PCSC and OESC requirements were introduced to reflect international developments regarding safety cases and safety assessments for radioactive waste disposal facilities, including guidance from, for example, the International Atomic Energy Agency. These developments seek to ensure that disposal systems are represented in a way that will assist stakeholders to assess their evolution and long term safety performance. As regards an operational facility such as Drigg, the aim is to provide sufficient assurance that it can continue to be operated and eventually be closed, using best available technology, so as to comply with current radiological protection standards.

5.8 It was apparent to RWMAC from the information provided during its visit to Drigg that BNFL and EA are committed to ensuring that the forthcoming review of the RSA93 authorisation for the site follows best international practice. Efforts are being made to enable the substantial body of information being generated in support of the review to be brought together and presented systematically. What is being done is meant to facilitate stakeholder involvement and help clarify the issues for decision.

Wider issues

5.9 The RWMAC site visits to Dounreay and Drigg underlined that both current operations and, more importantly, future intentions relating to LLW raise issues of more than local significance. At Dounreay, as previously indicated, the plans to provide a long-term management solution for LLW from the site are to be determined by carrying out a BPEO study. The most obvious options for consideration in the proposed study are the provision of new LLW disposal facilities in the vicinity of Dounreay, long-term storage of the waste at Dounreay, or transferring it for disposal at Drigg. Each of these options is likely to prove contentious to one degree or another and the selection process is bound to raise issues that will be of interest well beyond the immediate area of Dounreay. RWMAC believes that it would be wrong for the plans for Dounreay LLW to be formulated other than in the context of a strategy for the management of such waste in the UK as a whole. Despite the pressing need for a settled long-term management plan for Dounreay LLW, the Committee considers that the wider implications of the options should be exposed to national debate. It would seem appropriate that such a debate should be in the context of the Government's review of radioactive waste management policy - Managing Radioactive Waste Safely ⁴.

5.10 Although disposal space is not an immediate issue at Drigg, capacity is not unlimited and there is a need to ensure that it is used to best advantage given that it represents a valuable UK resource. The ability of the consented area to receive waste is constrained both by its physical volume and its radionuclide capacity. Optimum use of physical space can be achieved by restricting the specific activity of the waste disposed of. Conversely, the aim could be to optimise Drigg's radiological capacity at risk of leaving physical space unfilled. There is ongoing debate on the issues involving BNFL, its customers, and the regulators. In view of the importance of Drigg, RWMAC believes that it would be appropriate to reassess the use being made of the facility in strategic waste management terms and that this should be done as part of the Government's policy review.

5.11 On the question of a replacement for Drigg, the report of the Science and Technology Select Committee's enquiry into the management of nuclear waste ⁵ drew attention to predictions that, if its radiological capacity becomes exhausted, Drigg may not be able to accept LLW after about 2050 (or perhaps well before). The Select Committee recommended that : "Plans should be made for the establishment of a new LLW disposal facility, to open before Drigg closes." The Government's response included a commitment to use the promised public consultation on radioactive waste management policy, inter alia, to "invite views on the options for a possible successor to Drigg". The debate has been opened by reference in Managing Radioactive Waste Safely ⁴ to views being sought on the future of Drigg.

5.12 Given the uncertainties concerning the date when the capacity of the existing consented area at Drigg is likely to be exhausted and the time required for development of an extension or replacement, it is important, in RWMAC's view, that preparatory work should not be unnecessarily delayed. There are, in practice, a more open set of possibilities for future disposal of LLW than the replacement facility foreseen by the Select Committee. RWMAC's view of the present position is explained in the following paragraphs.

5.13 RWMAC's view is that attention needs to be paid to whether the UK currently possesses a strategy for the future management of solid LLW that is sufficiently robust to take on board all the issues likely to be raised. This view has been determined by a number of factors -

• estimates suggest that the capacity of the currently consented area at Drigg could be exhausted within 50 years and possibly sooner. It is important that this is taken account of in the Government's strategy for radioactive waste management. Plans for replacement, or extension, of Drigg need to put be in place well before it becomes full, given the long lead-times currently required for planning and regulatory approval of such developments;
• nuclear site decommissioning and remediation of radioactively contaminated land produce significant quantities of LLW. Failure to establish management solutions for such waste will impede decommissioning and remediation schemes;
• because the existing LLW disposal facility at Dounreay is virtually full, the provision of a management solution for current and future LLW arisings has been identified as a key output of the site restoration programme;
• one solution for Dounreay could be the transfer of LLW to Drigg, but this would increase the pressure on Drigg's existing volume and radiological capacity and would be likely to bring forward the date by which the consented area would have to be extended or an alternative established;
• transfer of Dounreay waste to Drigg would significantly raise the profile of cross-boundary waste movements with implications for UK devolution arrangements;
• Drigg provides for the disposal of LLW not just from the nuclear industry, but from a variety of other sources such medical practice and non-nuclear industries including those concerned with North Sea oil and gas; the service that Drigg provides is crucial and should be clearly recognised in a national strategy for LLW.

5.14 RWMAC believes that LLW management issues such as these, no less than those affecting ILW and HLW, need to be examined, and debated, as part of the Government's Managing Radioactive Waste Safely consultation ⁴. The outcome of the consultation must not be prejudged. Nevertheless, RWMAC's sponsoring Ministers have agreed that the Committee should address the UK's management arrangements for solid LLW as part of its future work programme (see chapter 3).

5.15 RWMAC sees a need for a more cohesive approach to policy for the management of solid LLW, taking particular account of future arisings and the means available for their disposal. The Committee hopes that its study will help to achieve this.

References

¹ The Radioactive Waste Management Advisory Committee's Advice to Ministers on the Process for Formulation of Future Policy for the Long Term Management of UK Solid Radioactive Waste, Department for Environment, Food and Rural Affairs, September 2001.

² Dounreay Site Restoration Plan, The United Kingdom Atomic Energy Authority, October 2000.

³ The Radioactive Waste Management Advisory Committee's Advice to Ministers on Restoration of the UKAEA Dounreay Nuclear Site, Department for Environment, Food and Rural Affairs, September 2001.

⁴ Managing Radioactive Waste Safely : Proposals for Developing a Policy for Managing Solid Radioactive Waste in the UK, Department for Environment, Food and Rural Affairs et al, September 2001.

⁵ Management of Nuclear Waste, Report of the House of Lords Select Committee on Science and Technology, The Stationery Office, March 1999.