Chemical Corrosion of Cogema Glass R7T7 in High Saline Brines

Abstract

AbstractIn the Federal Republic of Germany, the salt dome formation at Gorleben has been selected as a possible site for final disposal of HLW. The waste form will be borosilicate glass, e. g. the French Cogema glass R7T7. The corrosion of this glass has been investigated in three reference salt brines (brine 1: high Mg, brine 2: Ca and Mg, and brine 3: high Na) at three different temperatures, 110°, 150°, and 190°C and three S/V ratios, 10, 100, and 1000m−1. Results are presented for brine 1 and are compared qualitatively with those obtained for the other brines. As in deionized water and pure NaCl, the corrosion rate decreases when silica saturation is approached, but the reaction does not cease. The data after silica saturation were used to calculate upper limiting, i. e. time-independent corrosion rates. The long-term data indicate that a transport process through the growing surface layer may become rate controlling, and that the rate may further decrease after silica saturation.