Development of advanced reprocessing system using highly selective and controllable precipitants, 12; Precipitation tests with solutions dissolving spent nuclear fuels

Kawata, Yoshihisa; Kim, S.-Y.; Sato, Makoto; Morita, Yasuji  ; Ikeda, Yasuhisa*; Kikuchi, Toshiaki*

We have been developing an advanced reprocessing system for spent FBR fuels based on precipitation method using pyrrolidone derivatives. In the present study, the first precipitation step for selective U separation with N-n-butyl-2-pyrrolidone (NBP), concentration step and the second precipitation step for Pu and residual U separation with N-neopenthyl-2-pyrrolidone (NNpP) were tested using real fuel solution. U(VI) was precipitated as expected both in the first and second precipitation steps. In the concentration step, a part of Pu(IV) was oxidized to Pu(VI). The behavior pf Pu in the second precipitation step seemed to be influenced by the concentration step.