Nitric acid concentration dependence of dicesium plutonium(IV) nitrate formation during solution growth of uranyl nitrate hexahydrate
硝酸ウラニル六水和物の溶液成長における硝酸セシウムプルトニウム(IV)の生成に及ぼす硝酸濃度依存性
中原 将海; 鍛治 直也; 矢野 公彦 ; 柴田 淳広 ; 竹内 正行 ; 岡野 正紀 ; 久野 剛彦
Nakahara, Masaumi; Kaji, Naoya; Yano, Kimihiko; Shibata, Atsuhiro; Takeuchi, Masayuki; Okano, Masanori; Kuno, Takehiko
U晶析工程においてCsPu(NO)の生成挙動に及ぼすHNO濃度の依存性を調べた。硝酸ウラニル溶液に対するCsPu(NO)の溶解度は、HNO濃度が高くなるほど低下する傾向を示した。照射済高速炉燃料溶解液を用いた晶析実験では母液のHNO濃度が6.5mol/dmの条件において、CsPu(NO)が析出し、硝酸ウラニル六水和物結晶に対するCsの除染係数は低下した。一方、母液のHNO濃度が4.0mol/dmのときは、CsPu(NO)が生成せず、硝酸ウラニル六水和物結晶とCsが良好に分離できることを示した。
The influence of HNO concentration in the solution on the formation of CsPu(NO) was evaluated in the U crystallization process. The solubility of CsPu(NO) in a uranyl nitrate solution was found to decrease with increasing HNO concentration in the solution. In the U crystallization experiments with the dissolver solution of irradiated fast reactor fuel, CsPu(NO) formed with 6.5 mol/dm HNO concentration in the mother liquor, and the decontamination factor of Cs for the uranyl nitrate hexahydrate crystals was low. Meanwhile, CsPu(NO) did not precipitate with uranyl nitrate hexahydrate crystals under the condition of 4.0 mol/dm HNO concentration in the mother liquor, and Cs could be separated from the uranyl nitrate hexahydrate crystals.