Radiolysis and corrosion of stainless steel in high temperature water environment
Résumé
Radiolysis influences not only the electrochemical behaviour but also the oxide formation of stainless steel in high temperature water environments, like primary water of Pressurised Water Reactors (PWR).
This paper focus on the corrosion behaviour of austenitic 316L stainless steel in PWR primary water under the influence of radiolysis, including experimental devices and main obtained results.
After a short overview of the literature in the field, the approach is described with the use of a high energy proton beam to control the production of radiolytic species at the interface between stainless steel (316L type) and PWR water solution in a high temperature and high pressure electrochemical cell working up to 300°C and 100 bar.
The corrosion potential of stainless steel was enhanced by the radiolysis causing by high energy proton beam. A high similarity of electrochemical behaviour was also observed under electron beam.
The electrochemical oxidative response of the 316L/PWR solution interface under radiolysis is related to the surface characterization analysis (SEM, XPS, Raman spectroscopy, NRA…) on the oxide layers of 316L which are formed under or without irradiation. The radiolysis effect on the oxide film includes micron scale cavities which were observed in a highly irradiated oxide film. The observation of -Fe2O3 hematite on the outer oxide film where cavities were formed is in accordance with the electrochemical oxidative response.