AQUEOUS REPROCESSING OF THE FUEL ELEMENTS OF THE FAST BREEDER. THE COMBINED EXTRACTION AND SEPARATION OF MACROAMOUNTS OF PLUTONIUM AND URANIUM IN THE PUREX PROCESS.

For reprocessing irradiated fast breeder fuel elements by solvent extraction with 20% TBP/alkane coextraction, cobackwash, and partitioning of uranium and plutonium have been studied. In the coextraction and co-backwash countercurrent experiments, losses of plutonium and uranium to the aqueous raffinate (HAW)and to the organic extractant (HCW) remained below 0.l%. Partitioning of plutonium and uranium by reduction with uranium(IV) has been studied intensively, and has been compared with reduction by ferrous sulfamate. Countercurrent experiments resulted in plutonium losses to the uranium stream (lBU) of less than 0.2 %, while the decontamination of the plutonium product (lBP) from uranium yielded a decontamination factor of approx 10{sup 3}. (auth)