Development of a simple reprocessing process using selective precipitant for uranyl ions; Engineering studies for precipitating and separating systems

Yamasaki, Kazuhiko*; Chikazawa, Takahiro*; Tamaki, Yoshihisa*; Kikuchi, Toshiaki*; Morita, Yasuji  ; Kawata, Yoshihisa*; Mineo, Hideaki  ; Koshino, Nobuyoshi*; Asanuma, Noriko*; Harada, Masayuki*; Ikeda, Yasuhisa*

N-cyclohexyl-2-pyrrolidone (NCP), can selectively precipitate U(VI) ions in aqueous nitric acid solutions. Utilizing this property, we have been developing a simple reprocessing process of spent nuclear fuel based only on precipitation method. In the first precipitation step, only U is separated by precipitation in a yield of about 70%, and in the second precipitation step both U and Pu are recovered and separated from fission products (FP) and other transuranium elements (TRU). In the present study, a precipitator and a precipitate separator were designed and built up, and were tested with aspets of operationability and system performance.