The impact of interstitial hydrogen on interfacial reactions in Alloy 690 within lead-contaminated high temperature alkaline environments

Ab initio molecular dynamics (AIMD) simulations and density functional theory (DFT) are utilized to resolve the interfacial reactions in Alloy 690 under high temperature and high pressure Pb(OH) 2 solution. Pb ions preferentially bind to Ni atoms whereas Cr and Fe atoms exhibited preferential adsorption for OH − ions. Moreover, tetrahedral and octahedral interstitial H are taken into considerations for investigating the influence of interstitial H to the initial interaction. The tetrahedral interstitial H presented diffusion from Alloy 690 matrix. While H atoms occupying octahedral interstitial positions enhanced surface adsorption processes. These findings offer a predictive framework for understanding PbSCC and the impact of interstitial H on the interfacial reactions in Alloy 690 under high temperature and high pressure Pb(OH) 2 solution.