Uniform corrosion of hydrogen-charged copper and localized corrosion of non-charged copper in anoxic groundwater containing diluted sulfide

Hydrogen atom generation and permeation on nuclear waste storage canister surfaces threaten disposal safety. This study investigated the corrosion behavior of hydrogen-charged and non-charged copper in an anoxic, sulfide-containing groundwater environment simulating nuclear waste disposal conditions in Beishan, China. Chloride ions induced pitting corrosion in non-charged copper. The mass transfer rate of CuCl2¯ species within pitting pores was higher compared to that of Cu+ through the Cu2S layer, resulting in excessive thickening of corrosion products at pitting sites. By contrast, porous corrosion products on hydrogen-charged copper formed non-passivating films, leading to uniform substrate corrosion. The corrosion product thickness exhibited logarithmic growth over time. This predictable logarithmic growth pattern is crucial for reliable service life assessment of deep geological repositories rather than unpredictable pitting corrosion.