RWMAC's Advice to Ministers on the Radioactive Waste Implications of Reprocessing

2. BACKGROUND TO STUDY

It has been ten years since the last RWMAC review of reprocessing¹. Both the outcome of this previous review and a number of recent developments relevant to the reprocessing issue are considered in this section as background.

2.1 Previous RWMAC considerations of reprocessing

The history and purpose of the reprocessing of spent nuclear fuel in the context of the United Kingdom’s (UK’s) nuclear operations has changed over the years. A historical review of this is given in Annex 1. RWMAC last reported on the waste management implications of reprocessing in its Eleventh Annual Report published in 1990¹. The Committee at that time, drew a clear distinction between uranium metal (Magnox) and uranium oxide (THORP) spent fuel reprocessing.

It concluded that the reprocessing of Magnox spent fuel gave rise to the largest single contribution to the radiation exposure of the UK population from the nuclear fuel cycle. It added, however, that discharges of radioactive effluents from reprocessing operations at Sellafield had declined rapidly during the 1980s. It concluded that the provision of facilities to store the spent fuel which it foresaw, at that time, arising from the remaining lives of the Magnox reactors could not be justified, particularly given the uncertainty over the acceptability of spent Magnox fuel for direct disposal. The Committee therefore accepted that reprocessing of spent Magnox fuel should continue.

For oxide fuel, the Committee found that an illustrative comparison of the waste management impacts of early reprocessing, delayed reprocessing and not reprocessing at all had indicated that all three options have impacts which were small and comparable within the bounds of the uncertainties within the estimates. It also concluded that there were no compelling waste management reasons to reprocess oxide fuel early, or later, or at all. It observed, however that it might be prudent to reprocess on an early timescale spent AGR reactor fuel, which had, at that point, been in store underwater at Sellafield for some years.

2.2 The current UK Government policy context

UK Government policy for the management of both solid radioactive wastes and radioactive discharges is currently under review. In respect of solid wastes, Government is committed to issuing a consultation document to promote wider discussion of the issues involved and how they should be addressed. In respect of radioactive discharges, the Government issued a consultation document on the UK Strategy for Radioactive Discharges 2001-2020 in June 2000². It has also said that it will be putting out to consultation draft statutory guidance to the environment agencies on the way in which radioactive discharges are regulated.

Extant Government policy as set out in the previous administration’s 1995 policy Cm2919 White Paper³ is that the decision whether to reprocess spent oxide nuclear fuel, to extract reusable uranium and plutonium, or to hold it in long-term storage for direct disposal or reprocessing at some time in the future, is a matter for the commercial judgement of the owner of the spent fuel.

The current UK practice resulting from this policy, as later sections of this report make clear, is that much of the UK’s spent nuclear fuel, for one reason or another, continues to be reprocessed. This, in turn, is leading to growing stockpiles of reprocessed uranium and separated plutonium, given their current lack of use as recycled nuclear fuel.

The growing stockpile of separated plutonium is, in particular, a contentious issue that has been considered in recent years by the Royal Society⁴, the House of Lords Select Committee on Science and Technology⁵ and the House of Commons Select Committee on Trade and Industry⁶. All have commented on the security risk of this growing stockpile and whether or not it is really needed for future nuclear reactor fuel. Such observations cannot be taken to imply that a reduction in UK stocks by, say, a half will reduce the risk or needs for security by an equivalent factor. A need for effective oversight will remain whatever the amount held.

The Royal Society⁴ recommended that Government "reviews the strategy and options for stabilising and then reducing the (UK’s plutonium) stockpile". The House of Lords Select Committee on Science and Technology⁵ said that "the Government should develop a clear policy for the management of the UK’s stock of separated plutonium". It also recommended a policy of maintaining a minimum strategic stock, and declaring the remainder as waste. Whilst not addressing the issue of the future status of plutonium explicitly, the House of Commons Select Committee on Trade and Industry⁶ stated the view in its report that "plutonium separated from used fuel is no longer required by any end-user, but is increasingly regarded as a positively dangerous waste product".

The House of Commons Select Committee on Trade and Industry report⁶ noted a number of ongoing and potential difficulties being experienced by BNFL in respect of its existing and potential THORP customers in both the UK, notably British Energy, and abroad, notably in Japan and Germany. The Select Committee therefore recommended that BNFL should "address in its Corporate Plan the prospects of reprocessing … and identify the commercial implications of any shift in policy from reprocessing to storage"⁶. Immediately following publication of the Select Comment report, there were media reports of some existing customers wishing to curtail their existing reprocessing contracts, although none had actually done so as of the date of preparation of this report. Nevertheless, in overall terms, RWMAC takes this to suggest that it is liable to be difficult for BNFL to win new THORP contracts in the foreseeable future either from UK or overseas customers.

In its response to the House of Lords Select Committee report, RWMAC agreed that there could only be a limited use for the UK’s plutonium stock in the foreseeable future, and that the remainder should be declared a waste unless a credible reason for doing otherwise could be given⁷. The Committee acknowledged the implications that this would have for the way in which spent nuclear fuel is handled within the UK and the case for its reprocessing. This continues to be RWMAC’s position. The key need is for policy clarity in light of reasoned debate of the issues.

Another issue that will need to be addressed in the Government’s review of policy is that relating to waste substitution. Substitution is the process whereby a smaller additional amount of high level radioactive waste (HLW), equivalent in radiological terms to the intermediate and low level radioactive waste (ILW and LLW) produced from reprocessing, would be returned to overseas customers. In Cm2919³, the last Government administration reaffirmed a policy that the wastes from the reprocessing of foreign spent fuel should be returned to the country of origin, and the HLW should be returned as soon as practicable after vitrification (although it did not say anything about the timing of return of reprocessed uranium and separated plutonium). It accepted that this policy could be implemented by waste substitution, but considered it prudent for BNFL not to become irrevocably involved in waste substitution in the absence of appropriate disposal arrangements within the UK.

This policy would presumably allow BNFL to engage in LLW waste substitution now, given the existence of the Drigg LLW disposal facility. But they could not do so for ILW, given the failure of the Nirex repository programme. Waste return is contractually required within 25 years, and there is no prospect of an ILW waste disposal facility becoming available within the remaining part of this time allocation. This situation means that there is currently a policy vacuum with respect to waste substitution, which must be resolved in the forthcoming Government radioactive waste management review. An affirmation of the need to return wastes within 25 years coupled with the Cm2919 policy formulation would effectively debar substitution of ILW. The RWMAC’s view of substitution was contained in the consultation paper issued in respect of formulation of the Cm2919 policy⁸.

A further key consideration, that will need to be taken into account in future radioactive waste management, is the 1998 OSPAR Sintra agreement which committed the UK to:

- work towards achieving further substantial reductions or elimination of discharges, emissions and losses of radioactive substances by the year 2000 and

- ensure that discharges, emissions and losses of radioactive substances are reduced to levels where the additional concentrations in the marine environment above historic levels, resulting from such discharges, emissions and losses, are close to zero by year 2020

The way in which the Government proposes these commitments should be addressed is set out in its UK Strategy for Radioactive Discharges 2001-2020 consultation document² and is to be further refined in statutory guidance to the regulatory bodies. Final policy will, presumably, rest on the outcome of consultations on these issues. OSPAR issues are discussed further in section 7.5 of this report, and will be addressed more fully in RWMAC’s response to the consultation.