Development of advanced reprocessing system using high selective and controllable precipitants, 7; Precipitation behavior of U(VI) by novel precipitants with high hydrophobicity and NCP

Takao, Koichiro*; Noda, Kyoko*; Nogami, Masanobu*; Sugiyama, Yuichi*; Harada, Masayuki*; Ikeda, Yasuhisa*; Morita, Yasuji  ; Nishimura, Kenji*

Precipitation behavior of U(VI) and some fission products (FP) with pyrrolidone derivatives of N-(1,2-dimethyl)propyl-2-pyrrolidone (NDMProP) and N-neopenthyl-2-pyrrolidone (NNpP) in the solutions of U-FP mixture has been examined in order to evaluate their applicability to the U-Pu co-precipitation process in the reprocessing based only on precipitation method. We have previously developed a process with N-cyclohexyl-2-pyrrolidone (NCP). It was found that U(VI) was precipitated in a high yield with any of the three precipitants and the order of the precipitation ability for U(VI) was NCPNNpPNDMProP. Decontamination factors (DF) against FP except Zr(IV) and Mo(VI) in the U(VI) precipitation were over 100, and therefore NNpP and NDMProP can be used as an alternative precipitants to NCP.