Influence of alpha and gamma radiolysis on Pu retention in the solvent TBP/kerosene

In light of the issue of radiolysis of the solvent system in PUREX process, alpha and gamma radiation stability of tributyl phosphate (TBP)/kerosene (OK) have been studied in this paper, in which 238Pu dissolved in the organic phase and ⁶⁰Co are selected as alpha and gamma irradiation sources, respectively. The amount of the degradation products not easily removed after the washing process has been measured by the plutonium retention. The effects of the absorbed dose, the TBP volume fraction, the cumulative absorbed dose and the presence of UO₂ ²⁺ and Zr⁴⁺ on the radiolysis of the solvents have been investigated. The results have indicated that the Pu retention increases with the increase of the absorbed dose after alpha or gamma irradiation, and is larger for the solvent containing less TBP. There is competition between UO₂ ²⁺ and Pu⁴⁺ to complex with the degradation products, and Zr⁴⁺ accelerates the radiolysis of the system.