Gamma and alpha radiolysis of TBP solvent

In light of the problem of radiolysis of the solvent system in PUREX (plutonium uranium recovery by extraction) process, gamma and alpha irradiation stabilities of tributylphosphate (TBP)/n-dodecane/nitric acid system were studied using Co-60 gamma-rays and alpha particles from (PU)-P-238. The main degradation products, dibutyl phosphate (BDBP) and monobutyl phosphate (H2MBP) were detected by the gas chromatography-mass spectrometry (GC-MS), and the degradation products that could not be easily removed by the washing procedure were measured by the Pu retention. Effects of the absorbed dose, the HNO3 concentration, and the cumulative dose on the irradiation stability of the systems were investigated. The yields of HDBP, H2MBP and the Pu retention increased with the absorbed dose. The HNO3 concentration affected significantly on the yield of HDBP, but had little impact on the output of H2MBP and Pu retention. For a similar absorbed dose, the Pu retention of the solvent by alpha irradiation is larger than that by gamma irradiation.