ИСТИНА

The reprocessing of spent fuel is usually performed by the PUREX process [1]. The process currently includes the extraction of uranium, plutonium, and neptunium with 30% tri-n-butylphosphate (TBP) in a hydrocarbon solvent. In this process, uranium, plutonium, and neptunium are concentrated in the organic phase, and americium, curium, and fission products are concentrated in the aqueous phase. High_level radioactive wastes (HLRW) are further formed based on the aqueous phase. The concentration of target elements in HLRWs does not exceed 0.01, 0.025, and 0.5% with reference to uranium, plutonium, and neptunium, respectively. HLRW specific activities were determined by 90Sr and 137Cs fission products and americium and curium radionuclides. Now it is necessary to isolate americium and curium radionuclides. The process includes the following stages: (1) the separation of a mixture of rare_earth elements (fission products), americium, and curium from the aqueous phase of the extraction process; (2) the extraction separation of americium and curium from rare_earth elements. Here, there are the two possible variants: 1) the coextraction of americium and curium – DIAMEX – process; 2) the extraction of americium only, whereas curium remains in the aqueous phase EXAm -process. 1. Ochkin, A.V., Some problems in reprocessing of fuel spent by modern power reactors. Theor. Found. Chem. Eng., 2014, vol. 48, pp. 34–38.