Treatment of high-level radioactive waste arising from pyroprocessing and its waste form

Amamoto, Ippei

In this paper, the author has briefly introduced the development of pyroprocessing, highlighting the spent electrolyte treatment from the viewpoint of economical and environmental load reduction. The zeolite sorption method developed in USA is currently most progressive technique. There are other methods which use phosphates to treat the spent electrolyte, among them three are presented here, i.e., the phosphates precipitation method developed by RIAR, the GRSS method using SAP by KAERI, and the phosphate conversion method by JAEA. In the phosphate conversion method, the iron phosphate glass (IPG), which possesses unique properties, is employed for FP separation and FP immobilization. From preliminary experiments, it found that the IPG could separate insoluble FP in the spent electrolyte when used as a filtration medium. In addition, when used as a sorbent, it could remove the soluble FP. The IPG is regarded as a potential effective material to treat FP as well as the glass medium.