干法后处理中含氯放射性废熔盐固化方法研究进展

熔盐电解法处理乏燃料产生的废熔盐属于高放废物,该类废熔盐具有水溶性较高、元素复杂、放射性高、腐蚀性强及高挥发性等特点,需要将其封装在结构稳定、耐辐照的固化基材中,形成稳定的耐浸出固体废物,使其与人类生存环境隔绝。由于常规硅酸盐玻璃与氯化物相容性较低,无法直接用于固化废熔盐,因此,需要进行大量研究来寻找合适的固化材料。含氯废盐的处理有两种途径:一是选择合适的基体进行包容处理,常见基体有方钠石、磷灰石或磷酸盐玻璃;二是先把氯化物转化为其他形式化合物,如磷酸盐、氧化物等化合物,再进行固化处理。鉴于我国在该方面的研究起步较晚,本文综述了国内外已经开发的氯化物熔盐废物处理处置方法,介绍了每种方法的原理、路线和性能特点等。

Review on Solidification of Chlorine-Containing Radioactive Molten Salt Waste From Dry Reprocessing

The molten salt waste produced by disposal of spent fuel via molten salt electrolysis is classified as high-level waste. Because of high water solubility, complex elemental composition, high radioactivity, strong corrosiveness and high volatility, the nuclear waste forms used to immobilize molten salt waste needs to be thermal and chemical stabilities and irradiation resistance, which forms a stable leaching-resistant nuclear waste to isolate from the human living environment. Due to low compatibility with chloride, conventional silicate glass cannot be directly used to immobilize molten salt waste. Therefore, a great deal of research is focused on finding new suitable waste forms. This paper reviewed the treatment and disposal methods of chlorine-containing molten salt waste generated from reprocessing of spent fuel at home and abroad. There might be two routes to deal with chlorine-containing molten salt: the first one is to find a suitable host matrix for direct solidification, and common substrates are sodalite, apatite or phosphate glass; the second one is to convert the chloride to other forms of compounds, such as phosphates and oxides, followed by solidification. In view of the fact that China’s research in this field started late, this paper summarizes the chloride molten salt waste treatment and disposal methods that have been developed domestically and internationally, and introduces the principles, routes, and performance characteristics of each method.