Characterization of oxide scales formed on alloy 82 in nominal PWR primary water at 340 °C and in hydrogenated steam at 400 °C

Alloy 82, used as weld metal in Pressurized Water Reactor (PWR), was exposed to hydrogenated steam at 400 degrees C and to simulated primary water at 340 degrees C. A comparative study of the oxide layer formed on the alloy surface in both environments was performed to confirm that steam conditions were representative of accelerated primary water conditions. For this purpose, the oxidation products were investigated at a nanometer scale using Scanning Electron Microscopy (SEM), X-ray Photoelectron Spectrometry (XPS) and Transmission Electron Microscopy (TEM). Results obtained in both conditions are compared and the influences of heat treatment, test duration and surface preparation are studied.