HKNIC - Spent Fuel Reprocessing and Disposal
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Spent Fuel Reprocessing and Disposal

Spent nuclear fuel contains about 95% uranium 238 (U-238), 1% plutonium 239 (Pu-239), a fraction of a percent of uranium 235, 4% of highly radioactive fission products arising from the fission of U-235 for power production and a small quantity of other highly radioactive products formed in a process known as transmutation in which U-238, Pu-239 and their transmutation products absorb neutrons produced in nuclear fission events to become other radioactive nuclides. U-238 and Pu-239 contain a significant amount of energy and can be exploited for further use.

In a reprocessing facility, the spent fuel is separated by chemical processes into three components: uranium, plutonium and the remainder which collectively is known as high level waste or HLW. Reprocessing enables the uranium and plutonium to be recycled into fresh fuel, and reduces considerably the quantity of material that needs to be disposed at the end of the nuclear fuel cycle.

The uranium from reprocessing can be reused as the base material for fuel after undergoing conversion and enrichment.

Spent Fuel Reprocessing and Disposal

The plutonium can be directly made into an oxide to be mixed with uranium oxide, creating a mixed oxide fuel that can act as a substitute for U-235. This fuel can be used in a conventional nuclear power reactor. Alternatively, the plutonium can be used on its own as a fuel in a fast-neutron reactor.

Direct spent fuel disposal typically requires the spent fuel assembly to be sealed and stored underground in a stable geologically formation. Disposal facilities are now being developed to allow retrievable storage of spent fuel, which still contains a significant quantity of untapped energy.

See Managing Spent Fuel for more information.