Nuclear reprocessing

Nuclear reprocessing is the chemical separation of fission products and actinides from spent nuclear fuel. Originally, reprocessing was used to extract plutonium for producing nuclear weapons. With commercialization of nuclear power, reprocessed plutonium was recycled into MOX nuclear fuel for thermal reactors. Reprocessed uranium can in principle be re-used as fuel. Nuclear reprocessing may include the reprocessing of other nuclear reactor material, such as Zircaloy cladding.

The high radioactivity of spent fuel means that reprocessing must be controlled and executed in advanced facilities by specialized personnel. Numerous processes exist, dominated by the chemical-based PUREX process. Alternatives include heating to drive off volatile elements, oxidation, and fluoride volatility (which uses reactive fluorine gas). Each process results in some form of refined nuclear product, with radioactive waste as a byproduct. Because this could allow production of weapons grade nuclear material, nuclear reprocessing is a concern for nuclear proliferation.

Spent fuel reprocessing is relatively expensive compared to the once-through fuel cycle, but fuel use can be increased and waste volumes decreased. Reprocessing is performed routinely in Europe, Russia, and Japan. The United States halted commercial reprocessing plans in the 1970s but has continued to pursue reprocessing-related scientific research. Most nuclear fuel does not require reprocessing. Breeder reactors can use recycled plutonium and uranium as well as other actinides, closing the nuclear fuel cycle and potentially multiplying the energy extracted from natural uranium by ~60-fold and dramatically reducing long-lived high-level radioactive waste.

Spent nuclear fuel contains abundant fertile uranium and traces of fissile materials. Methods such as the PUREX process can be used to remove useful actinides for the production of active nuclear fuel.

Another option is to reuse specific isotopes. Caesium-137, strontium-90 and other isotopes are extracted for food irradiation and radioisotope thermoelectric generators. While re-use does not eliminate the need to manage radioisotopes, it can reduce the quantity of remaining waste.