Study on corrosion of T-22 alloy under high temperature condition of VHTR

Abstract

T-22 alloy is applied to the steam generator of the high-Temperature Reactor–Pebblebed Modules (HTR-PM). In this study, a corrosion experiment of T-22 alloy was carried out for 50 h under the environment of air, vacuum, and impure helium at ultra-high temperature (950°C). After the experiment, the corrosion behaviors of T-22 alloy were characterized and analyzed by electronic balance, scanning electron microscope (SEM), energy-dispersive spectroscopy (EDS), carbon sulfur analyzer, and gas chromatography. The results show that the T-22 alloy was seriously corroded and destroyed under the air ingress accident; in the vacuum environment, the alloy appeared mass loss and slight decarburization; in the impure helium environment, the microclimate reaction would occur on the surface of T-22 alloy, and the oxide on the surface of the alloy would be destroyed and the alloy decarburized obviously; CO₂ in the ppm range will accelerate the oxidation and decarburization of the alloy.