APPLYING SLIP-OXIDATION TO THE SCC OF AUSTENITIC MATERIALS IN BWR/PWR ENVIRONMENTS

摘要

The stress corrosion cracking (SCC) of austenitic materials in hot water has been investigated for years with a multitude of theories and models proposed. Researchers at GE have developed a methodology based on the slip-oxidation model that accurately predicts the SCC crack growth rate of austenitic stainless steels in boiling water nuclear reactor (BWR) environments. In developing the methodology, the fundamental parameters and complex interactions that control the slip-oxidation process have been studied, leading to the lifetime evaluation of components and the development of mitigation strategies. Based on these successes, studies are in progress to expand this model to characterize closely related systems such as nickel-base and low alloy steels in BWR and pressurized water nuclear reactor (PWR) environments. This paper will describe the critical concepts of the slip-oxidation process, the understanding accumulated to apply slip-oxidation to austenitic stainless steels in BWR environments, and the information required to apply this methodology to nickel-base alloys in BWR / PWR environments. This information includes quantification of the repassivation kinetics, oxide rupture strain and crack tip strain rate for the material-environmental conditions of interest for correlation with high quality crack growth rate data.