Management of the UK plutonium stockpile: the economic case for burning as MOX in new PWRs

Over the next decade the UK stockpile of plutonium will grow to over a hundred tonnes. The policy to date has been to regard this as a valuable energy resource and to store it for use as the fuel for fast breeder reactors at some future date. However fast reactors are unlikely to be built for several decades and the growing stock of plutonium is causing concern on both safety and proliferation grounds. Continued storage for future use is therefore becoming less tenable and the two alternative options, namely immobilisation of the plutonium as a waste for ultimate disposal or recycling it as MOX (mixed oxide fuel ) in nuclear reactors, now need to be considered. Since both options are technically feasible and there would be a demand for the power from the reactor option, the choice should depend on the relative economics of the two. The bulk of the plutonium is owned by the government and the problem is to find the most cost effective way of dealing with it from the 'UK plc' point of view. Under the current conditions in the electricity market there is no commercial case for building new PWRs (pressurised water reactors) only to burn the stockpile as MOX, and a government subsidy would be needed to allow this. The immobilisation option would also need government funding. Both options are considered here, and it is concluded that the burning of the UK stockpile of plutonium in new dedicated PWRs would result in a substantial cost saving to the UK, of between seven and twelve hundred million pounds sterling discounted. Additional factors in favour of the reactor option are that it would generate some three hundred terawatt hours of electricity, about the annual consumption in the UK, and that it could be based on proven technology which could be implemented now.