The Fast Reactor and the Plutonium Fuel Cycle

Publisher Summary This chapter provides an overview on fast reactor and the plutonium fuel cycle. Nuclear power can contribute to world energy by means of natural, or lightly enriched, uranium burned in the thermal reactor. This contribution is limited by the amount of uranium that can be mined economically. By adopting fast breeders, the energy availability of uranium can be increased by a factor of up to 100. There are some respects in which a fast reactor is safer than some kinds of thermal reactor, and, indeed, it is extremely stable in normal operation. The fast breeder reactor is cooled by low-pressure liquid sodium that can absorb large amounts of heat without boiling. By contrast, fast neutron fluxes are about 1,000 times higher in fast reactors and this may be enough to generate mechanical failures absent from thermal reactors. Fast reactor fuel is a mixture of plutonium and uranium oxides. As the plutonium is burned by fission, fresh plutonium accumulates by transmutation of the uranium. The plutonium fuel is obtained by separating it chemically from irradiated fuel from both fast and thermal reactors. A reprocessing plant is required, and it is likely that fuel will be reprocessed half-a-dozen times in the course of its life in the fast reactor.