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

ANNEX 1

HISTORY AND PURPOSE OF REPROCESSING IN THE UK CONTEXT

Reprocessing of spent fuel allows the unburnt fissile uranium and fissile isotopes of plutonium, which have been created in the nuclear reactor, to be extracted for potential further use as nuclear fuel. The United Kingdom, France and Russia are currently the only European countries carrying out reprocessing. A number of other nations, including the United States, have stopped reprocessing. The first reprocessing plants in the United Kingdom (there have been six in all) were built to separate plutonium for military purposes, and the early nuclear reactors produced no useable power but were used solely to produce plutonium. In the mid-1950s, two new military Magnox installations were commissioned at Calder Hall and Chapelcross. Although their primary purpose was the production of military plutonium, they were also used to generate electricity.

Not least because of its military associations, intention has therefore always been that spent fuel from the Magnox reactors should be reprocessed and should not undergo long-term storage. In its Sixth Annual Report in 1985, RWMAC noted that Magnox fuel needed to be reprocessed soon after discharge from the reactor. This was because, with the exception of one power station, Wylfa, the spent fuel was stored in water and the fuel cladding was subject to corrosion, which in time could lead to the release of radioactivity from the fuel. Also, a substantial quantity of Advanced Gas Cooled Reactor (AGR) fuel had already been stored under water for many years and reprocessing in the proposed BNFL’s Thermal Oxide Reprocessing Plant (THORP) was considered the only technical option available, although this fuel was much more stable than Magnox. With respect to AGR fuel, the Central Electricity Generating Board (CEGB) had already stated its intention to build dry stores which would in effect keep the direct disposal alternative open. For Pressurised Water Reactors (PWRs), storage under water would not close any options. A decision on whether to reprocess or dispose directly would depend on future policy with regard to nuclear reactors.

The CEGB’s evidence for the Sizewell B Public Inquiry, held from 1983-85 and reported in 1987, put forward a number of options for the long-term management of spent oxide fuel. It was noted by the RWMAC at this time that provision for the reprocessing of a first tranche of AGR fuel had been made in the proposed THORP, but decisions on the use of THORP beyond its first ten years of operations would determine whether AGR fuel would need to be stored for substantial periods. This would entail the need for the construction of a dry fuel store. For PWR fuel, storage in water had been carried out internationally for some decades. France was extending its reprocessing programme but had, at that time, made no firm commitment as to what its policy on reprocessing would be in the late 1990s.

Justice Parker, the Inspector at the THORP inquiry, concluded that early reprocessing of spent oxide fuel was preferable to storage. This was because of the difficulties of storing the increasing volumes of spent fuel which were expected to arise with the nuclear power programme then envisaged, and because delay before reprocessing was not perceived to have any advantages. The Inspector concluded that disposal of spent fuel would not be in the best interest of either current or future generations because it involved throwing away indigenous energy sources and because, by removing plutonium from waste and using it in fast reactors, reprocessing would reduce the risk to future generations from the disposal of this plutonium. The Inspector considered the risks from the emissions involved in reprocessing to be very small, and that the advantages of reprocessing foreign spent fuel outweighed the disadvantages.

Chapter 4 of the RWMAC’s Eleventh Annual Report, 1990, addressed the waste management implications of reprocessing. The rationale for reprocessing was reviewed. In the early years of the UK’s nuclear power programme, it was envisaged that electricity demand would continue expanding substantially over the decades and that economic supplies of uranium would become scarce. The United Kingdom has no proven uranium deposits of its own and is dependent on imports. The availability of fissile plutonium, together with existing stocks of depleted uranium, if used in fast reactors, potentially offered long term independence from imported uranium, and significant strategic advantages.

However, the uranium market was destabilised by the uranium stockpiling that occurred in the late 1970s and early 1980s. The political changes in 1989 with the end of the Cold War, have destabilised the market still further by massive sales by countries from the CIS, formerly Russia, at prices that are well below marginal production costs of the most productive western mines. In the western world, uranium production has continued to fall. BNFL formally announced the end of Magnox reprocessing for military purposes in April 1995.

Hence, the rationale for reprocessing has become more questionable over the years. As well as the ending of the military requirement for plutonium, the reduction in the expected size of the nuclear power programmes, the discovery of new sources of uranium and the reduction in the price of uranium has reduced the strategic incentive for fast reactors. Indeed, the United Kingdom’s only fast reactor at Dounreay was shut down in April 1994.

Reprocessing became an issue for public debate, yet again, when in 1992 THORP was ready to start up. As part of the triennial review cycle of discharge authorisations, BNFL was required by the Authorising Departments to seek a change in the radioactive discharge authorisations for its Sellafield site. The new discharge limits, which included those from THORP, had also to take into account the start-up of new Low Active Effluent Treatment (LAET) plants including most significantly the Enhanced Actinide Recovery Plant (EARP).

After two rounds of consultation, in November 1992 and June 1993, the commissioning of THORP with uranium commenced on September 1993 under a variation of the existing authorisation. The revised discharge authorisation was issued in December by the Authorising Departments but did not take effect until one month later. The Government’s December decision was subsequently challenged unsuccessfully in the High Court by Greenpeace and Lancashire County Council. Active commissioning began on 17 January 1994 with the movement of radioactive fuel into the Feed Pond. Active commissioning of the head end section began with the first shearing of fuel from the Heysham nuclear power station on the 27 March 1994. Active commissioning of the THORP chemical separation section began on 30 January 1995. The Government confirmed that the question of whether and when to reprocess spent nuclear fuel should be for the commercial judgement of the nuclear operators in its July 1995 Cm2919 policy statement.

Whilst THORP reprocessing has continued since that date, the Ninth Select Committee on Trade and Industry report on the Proposed Public Private Partnership for BNFL issued in May 2000 noted that this has not been without engineering problems. The plant was shut down for several months in 1998 and again in 1999. Equally, the Select Committee observes that in the financial year to 31 March 2000, THORP’s performance, in the reprocessing of 830 tHM, was good. However, this was to be set against a general background where the prospects for winning additional overseas reprocessing work were seen to have diminished over the previous two years.