Nuclear reprocessing technology was developed to chemically separate and recover fissionable plutonium from irradiated nuclear fuel. Reprocessing serves multiple purposes, whose relative importance has changed over time. Originally, reprocessing was used solely to extract plutonium for producing
nuclear weapons. With the commercialization of
nuclear power, the reprocessed plutonium was recycled back into
MOX nuclear fuel for
thermal reactors. The
reprocessed uranium, which constitutes the bulk of the spent fuel material, can in principle also be re-used as fuel, but that is only economic when uranium prices are high. Finally, a
breeder reactor is not restricted to using recycled plutonium and uranium. It can employ all the
actinides, closing the
nuclear fuel cycle and potentially multiplying the energy extracted from
natural uranium by about 60 times.