Role of Cavity Formation on Long-Term Stress Corrosion Cracking Initiation: A Review

Plant life extension from the initial licensed life to beyond 60 years is now being discussed for light water cooled nuclear powered reactors (LWRs). Reliable prediction for material degradation is extremely important to keep the reliability of LWRs during such long-term operation. One of the specific perspectives for this prediction is to take into account the changes in material properties during long-term operation, such as cavity formation, even at the LWR operating temperature. The mechanism of cavity formation and the associated phenomena are closely intertwined with interdisciplinary technological and scientific knowledge. Therefore, historical key knowledge from both phenomenological and fundamental research studies related to cavity formation was first reviewed to understand the overall picture. Subsequently, current research results related to long-term stress corrosion cracking initiation in the LWR environment were summarized to explain what is known, what is still unknown, and what are the critical remaining subjects.