Effect of crystal size on purity of uranyl nitrate hexahydrate crystalline particles grown in nitric acid medium

Abstract

Abstract Crystal washing experiments were carried out using a uranyl nitrate solution in order to confirm the effect of uranyl nitrate hexahydrate (UNH) crystalline particle size on the removal of liquid impurities. The UNH crystal was immersed in a Ce solution and was washed for removing the mother liquor on the surface of the UNH crystals. Larger UNH crystals were advantageous for increasing the decontamination factors (DFs) of liquid impurities. The large crystal size reduced the specific surface area of the crystals which in turn decreased the adhesion of liquid impurities on the surface of the crystals. Therefore, high DFs of liquid impurities were achieved before and after washing. In the crystallization experiments, the DFs of metals for the UNH crystal were evaluated using a dissolver solution derived from irradiated fast neutron reactor core fuel. The UNH crystal size did not affect the decontamination of solid impurities such as Ba and Np even after crystal washing in the U crystallization experiments.