Corrosion behavior of simulated HLW glass in the presence of magnesium ion

Maeda, Toshikatsu; Omori, Hiroyuki*; Mitsui, Seiichiro  ; Bamba, Tsunetaka

Static leach tests were conducted for simulated HLW glass in MgCl solution for up to 92 days to investigate the dissolution mechanism of HLW glass under coastal repository condition. Under the condition that magnesium ion exists in leachate, the dissolution rate of the glass did not decrease with time during leaching, while the rate decreased when the magnesium ion depleted in the leachate. In addition, precipitated layer consist of magnesium/silica was observed at the surface of the glass after the leach tests. The present results imply that dissolution of the glass is accompanied with formation of magnesium silicate consuming silica; a glass network former. As a consequence, the glass dissolved with an initial high dissolution rate.