Plutonium was first created in 1942 as part of the Manhattan Project when Seaborg bombarded uranium-238 with deuterium particles. He was then able to separate microgram quantities using a bismuth phosphate precipitation process. But kilogram quantities were needed to make a bomb and large nuclear reactors were therefore built at Hanford (first operation 1944) in which many tonnes of natural uranium were exposed to low levels of neutron irradiation. The bismuth phosphate precipitation process was scaled up but the operation was not continuous and, given the small amount of plutonium within the fuel, needed to be repeated several times to reach adequate purity. After the war, the Americans turned their efforts towards solvent extraction, till then used as an analytical method for trace compounds. This separation technique enabled homogeneous phase continuous counter-current extraction operations to reach very high plutonium decontamination factors. Several organic solvents were tested and, eventually, tri-butyl-phosphate (TBP) diluted in an alkane was selected for the PUREX process. This was first implemented at an industrial scale (for military purposes) at the Savannah River plant (USA) in 1954 with another plant opening at Hanford the following year when other methods of extraction stopped.

Similar military plutonium production reactors (in which natural uranium is taken to low burn-up levels) and associated reprocessing plants were started up at Windscale (now Sellafield) in the United Kingdom, Marcoule in France and Mayak in the Soviet Union.

Subsequently, reprocessing began to be used for commercial purposes with a focus on recycling and, especially, separation of plutonium for use in fast reactors. In the USA the first commercial reprocessing plant was opened at West Valley (NY), which was operated by Nuclear Fuel Services from 1966 till 1972. The plant (300 t/year capacity) treated 630 t of fuel. Shutdown was due to high retrofit costs associated with changing safety and environmental regulations and construction of the larger Barnwell facility. Construction of the Morris (IL) facility (General Electric) was halted in 1972 and never operated.

Barnwell (SC) sized for 1500 t/year (Allied Chemicals-Gulf Atomics) never received the required authorisation from the American regulatory bodies and in 1977 all commercial reprocessing on US territory was banned, which is not the case elsewhere in the world. Appendix 1 outlines industrial reprocessing activities in the UK, Japan, Russia and France.