Oxidation-Driven Lithium Uptake in Nickel-Base Alloys – Smoking-Gun Evidence for an Inner Cathode under LWR Conditions

Lithium hydroxide is a common pH buffer in pressurized water reactors. Recent studies have raised concerns about enhanced corrosion associated with Li⁺ enrichment near the alloy/oxide interface in chromia-forming Ni-based alloys. An inner-cathode mechanism for proton reduction was recently validated, and in this context, lithium can be considered a tracer for proton transport. Comparative analyses of interfaces containing either H or Li show that both species (a) promote chromium oxidation and (b) catalyze precipitation of nickel particulates within the oxide scale. These processes threaten the structural integrity of the protective scale, underscoring the need to investigate alternative pH-buffering strategies.