Nuclear Techniques ›› 2018, Vol. 41 ›› Issue (12): 120301-120301.doi: 10.11889/j.0253-3219.2018.hjs.41.120301


The influence of fluorides on the distillation behaviors of molten LiCl-KCl

YANG Tianhong1,2, LUO Yan1, FU Haiying1, GONG Yu1   

  1. 1 Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China;
    2 University of Chinese Academy of Sciences, Beijing 100049, China
  • Received:2018-09-20 Revised:2018-10-10 Online:2018-12-10 Published:2018-12-13
  • Supported by:
    Supported by the Strategic Priority Program of Chinese Academy of Sciences (No.XDA02030000), the Frontier Science Key Program of Chinese Academy of Sciences (No.QYZDY-SSWJSC016), National Natural Science Foundation of China (No.21771188)

Abstract: [Background] Recycling the chloride salt from the fission product fluoride and chloride salt mixture is important to the research and development of electrolytic separation technology for actinides and fission products fluoride. Low pressure distillation is a powerful technique, but the experimental data on the distillation behaviors of fluoride doped chloride salts are limited.[Purpose] This study aims at the experimental results which provide a basic understanding on the behaviors of fluoride doped molten chlorides during low pressure distillation.[Methods] The distillation behaviors of various fluoride doped molten chlorides at 1050 K and 130 Pa were studied in a pipe furnace. Salt vapor was condensed and collected on stainless steel foil 5 cm away from the crucible.[Results] With the increase of evaporation ratio, the decontamination coefficient of Ce decreases at 1050 K and 130 Pa in the salt collected by 5% CeF3-LiCl-KCl low pressure distillation. For the LiCl-KCl salts containing CeF3, NdF3, LaF3 and SrF2 respectively, the corresponding decontamination factors of the collected salts are on the order of 103 at the evaporation ratio of 95%. The decontamination factor of EuF3-LiCl-KCl system is very low, which may due to the presence of more volatile EuF2 at 1050 K, while the high vapor pressure of ZrF4is responsible for the low decontamination factor of zirconium in the case of ZrF4-LiCl-KCl.[Conclusion] The distillation behaviors of LiCl-KCl are affected by the nature of fission product fluorides as well as the evaporation ratio of the salt mixtures. The collected chloride salt mixture from low pressure distillation of CeF3-LiCl-KCl has a similar composition with the LiCl-KCl eutectic, and the content of fluoride is low enough.

Key words: Low pressure distillation, LiCl-KCl, Fluoride, Fission product, Decontamination factor

CLC Number: 

  • TL426