Characteristics of Dicesium Plutonium(IV) Nitrate Formation in Separation System of Uranyl Nitrate Hexahydrate Crystal

There is a concerned that Cs and Pu double salt Cs2Pu(NO3)6 is formed under certain conditions in the course of U crystallization. The influence of the Cs concentration in a feed solution on Cs2Pu(NO3)6 formation was thus examined in the U crystallization process. Cesium and Pu were decontaminated after crystal washing with a decreasing Cs concentration in the feed solution. Although Cs remained in the mother liquor at a Cs concentration of 1.0 g/dm3 in the feed solution, Cs2Pu(NO3)6 precipitated at a Cs concentration of 2.2 g/dm3. There is, therefore, a lower limit for the Cs concentration in the feed solution at which Cs2Pu(NO3)6 precipitates, and this limit falls in the range from 1.0 to 2.2 g/dm3 Cs.