An insight into PWR primary water SCC mechanisms by comparing surface and crack oxidation. (March 2019)

• Record Type: Journal Article
• Authors: Shen, Zhao; Du, Donghai; Zhang, Lefu; Lozano-Perez, Sergio
• Is Part Of: Corrosion science. Volume 148(2019)
• Page Start: 213
• Page End: 227
• Publication Date: 2019-03
• Subjects: Stainless steel -- Surface oxidation -- Crack tip oxidation -- Stress corrosion cracking -- Transmission electron microscopy; Corrosion and anti-corrosives -- Periodicals; 620.11223
• DOI: 10.1016/j.corsci.2018.12.020
• Languages: English
• ISSNs: 0010-938X

Abstract

Highlights: Surface oxide film on 316 L SS has triplex structure and the mechanisms are discussed. Mechanisms controlling the surface oxidation and crack tip oxidation are similar. Dislocation and stress can enhance oxidation. The formation of Ni-rich zone ahead of crack tip and in the surface oxide is controlled by selective oxidation. Abstract: Oxidation and stress corrosion cracking (SCC) of 316L stainless steel were studied in simulated pressurized water reactor primary water. Surface, crack flank, and crack tip oxides were analyzed and compared by high-resolution characterization, including oxidation state mapping. All oxides were found to have a triplex structure, although of different dimensions and composition, revealing the effects of local water chemistry and applied stress. The higher oxidation rate at the crack tip could be explained due to the existence of a higher dislocation density, higher level of stress and cation unavailability from the environment. The implications to SCC mechanisms are discussed.