PNNL

Abstract

This report summarizes the refractory corrosion data for a matrix of direct-feed high-level waste (DFHLW) glasses generated to expand glass property data into the high sulfur composition region. The design of the high sulfur glass matrix, HS24, was reported in Reiser et al. (2026). Fifty HS24 glasses were tested for the corrosion of Monofrax® K-3 refractory materials. The corrosion of K-3 refractory materials in the HS24 glass melts was measured using a static crucible method. Two test conditions, 1150 °C/7 days and 1200 °C/7 days, were applied. The melt-line neck corrosion depth of the test coupons was measured by micro-computed tomography (micro-CT). The measured K-3 neck corrosion values were compared to predicted values using the EWG3.0 K-3 corrosion model (Lu et al. 2026). Proposed upper limits for K-3 neck corrosion, 0.04 in. and 0.025 in. were applied to evaluate the neck corrosion data of the HS24 matrix glasses. Two glasses of this HS24 matrix were designed as replicates of glasses previously tested by different laboratories. The inter-laboratory discrepancies of the test results were analyzed and are discussed.