Effect of Pre-charged Hydrogen on the Oxide Film of 316L Stainless Steel in Simulated PWR Primary Water

Through scanning electron microscopy and X-ray photoelectron spectroscopy, the thickness and composition of the oxide films formed on the surfaces of cold-worked 316L stainless steel with and without hydrogen-charging after immersion in deoxidized simulated PWR primary water at 300 ℃ for 168 h were analyzed. The results show that the oxide films of samples with and without hydrogen-charging were all double-layer structures. The oxide particles of the outer oxide film were rich in Fe, and the oxide particles of the inner oxide film were rich in Cr. The thickness of the hydrogen-charging sample oxide film increased, the oxide particles of the outer oxide film were larger and the ratio of Fe mass fraction to Cr mass fraction was greater, compared to the sample without hydrogen-charging. The hydrogen charging increased the Fe content of the inner oxide film of sample, increased the OH^- and O^2- atomic fraction ratio, inhibitted the formation of Cr oxide, and reduced the Cr content of oxide film, thereby reducing the protection of the oxide film and accelerating the oxidation of the substrate.