Long-Term Prediction of Localized Corrosion of Alloy 825 in High-Level Nuclear Waste Repository Environments

Abstract

Abstract Long-term prediction of localized corrosion of high-level nuclear waste container materials is a necessary step in the performance assessment of the engineered barrier system. Localized corrosion of corrosion-resistant materials may occur if the containers are exposed to chloride (Cl−)-containing ground water at elevated temperatures. Potentiostatic tests conducted on alloy 825 (UNS N08825), a candidate container material, have shown that the potential at which localized corrosion can be initiated is a function of surface conditions and exposure time. The initiation potentials for localized corrosion measured in short-term tests with polished specimens overestimated the long-term initiation potentials by as much as 300 mV. On the other hand, the repassivation potential obtained from short-term tests on deep pits can be used to predict the initiation of localized corrosion in long-term tests.