The corrosion mechanisms of alloy N10276 tubing exposed to hydrothermal and supercritical HCl-containing solutions is investigated through post-failure analysis of laboratory-scale preheaters and
controlled-exposure experiments. Corrosion modes observed include dealloying of nickel and iron, intergranular corrosion, and stress corrosion cracking (SCC). Exposure temperatures are ascertained
through detailed heat-transfer models and direct measurements. A correlation between the dealloying rate and the temperature and dielectric constant of the water is developed.