Journal of Nuclear Fuel Cycle and Waste Technology

Layer crystallization process was tested for the separation(or concentration) of cesium and strontium fission products in a LiCl waste salt generated from an electrolytic reduction process of a spent oxide fuel. In a crystallization process, impurities (CsCl and SrCl2) are concentrated in a small fraction of the LiCl salt by the solubility difference between the melt phase and the crystal phase. Based on the phase diagram of LiCl-CsCl-SrCl2 system, the separation possibility by using crystallization was determined and the molten salt temperature profile during layer crystallization operation was predicted by using mathematical calculation. In the layer crystallization process, the crystal growth rate strongly affects the crystal structure and therefore the separation efficiency. In the conditions of about 20-25 l/min cooling air flow rate and less than 0.2 g/min/cm2 crystal flux, the separation efficiency of both CsCl and SrCl2 showed about 90 % by the layer crystallization process, assuming a LiCl salt reuse rate of 90 wt%.

Keywords

pyroprocessing,LiCl salt waste,reuse,Cs/Sr separation,layer crystallization