Use of mixed-oxide fuels

There are two main types of fuel used in nuclear power plants: uranium-oxide (UO2) fuel and mixed-oxide (MOX) fuel. The burning of UO2 fuel produces plutonium, which in spent fuel can be directly disposed of as nuclear waste or, after reprocessing, can be used in MOX fuel. One of the advantages of recycling is to limit the total amount of plutonium being produced. Surplus plutonium from defence programmes, which has grown to 68 metric tons in the framework of disarmament agreements. can also be recycled in MOX fuel. Several OECD countries use plutonium recovered from spent fuel in the form of MOX fuel in existing power plants. In France, 16 pressurised water reactors (PWRs) utilize MOX fuel and it is planned to introduce MOX fuel progressively in 4 more in coming years. Germany and Switzerland have experience in using MOX both in PWRs and boiling water reactors (BWRs). France and Japan also have experience in using MOX fuel in fast reactors and advanced thermal reactors. All of these countries report that the operation of existing reactors with MOX fuel is satisfactory and that MOX core behaviour is equivalent to that of conventional UO2 core behaviour from the standpoints of operation and safety. (authors)