Corrosion behavior of simulated LLW glasses in deionized water

Maeda, Toshikatsu; Yamaguchi, Tetsuji ; Hotta, Katsutoshi*; Mizuno, Tsuyoshi*; Bamba, Tsunetaka

Static leach tests were conducted for simulated low-level radioactive waste (LLW) glass in deionized water at 90 degrees Centigrade for up to one year. The objective is to investigate a dissolution mechanism of LLW glass by reference to widely observed leaching behavior for high-level radioactive waste (HLW) glasses. The release rates of boron, widely used as an index of dissolution for HLW glasses, decreased with time during the test period, which is commonly observed in similar tests for HLW glasses. In the leachate compositions of the present tests, a zeolite mineral (analcime) is thermodynamically more stable than amorphous silica which is known to analogous to HLW glasses. The present results imply that dissolution of the LLW glass is accompanied with formation of analcime under geologic disposal conditions where the groundwater flow is quite low.