干法后处理废盐中活泼裂片元素的净化工艺研究进展

随着快堆研究的快速发展,干法后处理工艺流程也逐渐成为了研究重点,熔盐电解干法后处理是未来先进核燃料循环系统的核心环节和关键技术。氯化锂-氯化钾共晶盐是干法后处理工艺中最常用的熔盐体系。为了提取乏燃料中的锕系、镧系和铯、锶元素,需要对熔盐进行长时间的电解。在锕系分离提取过程中,镧系和铯、锶等活泼裂片元素在熔盐中不断积累,不仅会改变熔盐体系的理化性质,还将影响后续锕系产品的净化效果。为实现溶剂盐复用,使放射性废物最小化,需定期对废熔盐中的镧系和铯、锶等活泼裂片元素进行净化处理。对干法后处理氯化锂-氯化钾废熔盐中镧系和铯、锶等活泼裂片元素采取的净化工艺,包括熔盐萃取法、熔盐电解法、沉淀法、区域精炼法等工艺的原理、特点和研发进展进行了综述和比较分析,讨论了上述工艺中为实现溶剂盐复用、减少放射性废物产生对废熔盐中的镧系和铯、锶等活泼裂片元素的净化效果。指出了中国废盐净化将围绕实现稀土资源利用最大化、保护环境、最大程度上减少废物的排放开展相关方向的研究。

Research progress on purification process for active crack elements in waste salt by dry post-treatment

With the rapid development of fast reactor research,dry post-treatment process has gradually become the focus of research.Molten salt electrolysis dry post-treatment is the core link and key technology of advanced nuclear fuel cycle system in the future.LiCl-KCl eutectic salt is the most commonly used molten salt system in the dry post-processing process.In order to extract actinides,lanthanides and strontium cesium elements from spent fuel,it is necessary to conduct long time electrolysis in the molten salt.In the process of separation and extraction of actinides,active fragment elements such as lanthanides,strontium and cesium accumulate in molten salt,which not only changes the physical and chemical properties of molten salt system,but also affects the purification effect of subsequent actinides products.In order to realize the reuse of solvent salt and minimize radioactive waste,it is necessary to regularly purify the lanthanide,cesium,strontium and other active fission elements in the waste molten salt.The principles,characteristics and development progress of the purification processes of lanthanide,strontium and cesium in LiCl-KCl waste molten salt by dry post-treatment were reviewed and compared,including molten salt extraction,molten salt electrolysis,precipitation and regional refining.The purification effects of lanthanide and active fragment elements such as strontium and cesium in waste molten salt were discussed in order to reuse solvent salt and reduce the generation of radioactive waste in the above process.It was pointed out that research of China′s waste salt purification will focus on maximizing the utilization of rare earth resources,protecting the environment and reducing waste emission to the greatest extent.