LOCALIZED CORROSION INITIATION, PROPAGATION, AND REPASSIVATION OF CORROSION RESISTANT HIGH-LEVEL NUCLEAR WASTE CONTAINER MATERIALS

摘要

The initiation and repassivation of pitting and crevice corrosion of two candidate high-level nuclear waste container materials, type 316L stainless steel and alloy 825, were examined under a range of environmental conditions possible in a repository. The initiation and repassivation potentials for localized corrosion in short-term tests were determined to be a function of temperature, chloride concentration, and potential. Under long-term potentiostatic conditions, pitting and crevice corrosion were initiated at potentials much lower than those measured in short-term tests. Crevice corrosion occurred preferentially over pitting corrosion. Similar results were obtained when creviced specimens were connected through a zero resistance ammeter to a boldly exposed cathode of the same material. Localized corrosion was only observed when the potential of the creviced specimen was higher than the repassivation potential.