Short communication on the Influence of the temperature between 30 and 70°C on the hydration of SON68 nuclear waste glass in a vapour phase

The hydration of SON68 glass (non-radioactive surrogate for R7T7 glass, the French industrial glass for high-level radioactive waste management) was studied at between 30 and 70°C at a relative humidity of 95% for a period of 6 months. The hydration thicknesses were shown to increase with temperature and did not exceed a few nanometres at 30 and 50°C, or a few tens of nanometres at 70°C. The temperature dependence of hydration rates followed Arrhenius law and enabled the determination of an activation energy. This is 62 ± 13 kJ.mol−1, which is compatible with a hydration mechanism involving a hydrolysis of the silicate bonds. All these results are discussed, taking into account data available in the literature.