Changes to Plutonium Extraction Behavior of TBP and Alkylamines through Irradiation

Abstract

Changes to plutonium extraction properties brought about through irradiation of 30v/o TBP (Tri-n-butyl phosphate)/kerosene and 5v/o alkylamines/kerosene modified with lauryl alcohol were studied in such respects as extraction, scrubbing and stripping characteristics in nitrate media. The alkylamines examined were tri-n-octyl amine (TOA), N-cyclohexyl dilauryl amine (N-CHDLA) and Amberlite LA-2 (LA-2). These extractante were irradiated to the extent of 108R by 60Co γ-ray, prior to extraction. Marked changes with irradiation were observed in plutonium extraction performance with the TBP system tending to bring losses of plutonium, but very little change was found to occur with amine systems. Calculation of the single stage decontamination factors of fission products from plutonium proved that separation deteriorated with irradiation in the TBP system but hardly changed in the amine systems. From these findings, tertiary amines, especially N-CHDLA, can be judged superior to TBP for the direct recovery of plutonium from irradiated fuels, a process that has to be carried out under high irradiation. The phase separation time after mixing in the extraction stage varied very little with irradiation, and no formation of emulsion occurred in the extraction of tracer plutonium with either irradiated TBP or amines.