Combination of physical and chemical separating procedures through which the substances uranium and plutonium (in the form of chemical compounds) are retrieved from spent fuel elements and the high-radioactive waste is separated. On a large technical scale mainly the so-called PUREX method is used for reprocessing (Plutonium Uranium Reduction Extraction Method).

In the Federal Republic of Germany spent fuel elements were reprocessed for test purposes in a pilot plant from 1971 to 1990 (Karlsruhe reprocessing plant, WAK). Reprocessing operations were discontinued at the end of 1990 and the facility was decommissioned. It is presently being dismantled.