Systematization of assessment techniques of stress corrosion cracking for in-vessel components and piping in BWRs and PWRs

Kato, Chiaki   ; Yamamoto, Masahiro ; Tsujikawa, Shigeo*; Hattori, Shigeo*; Yoshii, Tsuguyasu*; Kudo, Takeo*; Nemoto, Rikio*; Akashi, Masatsune*

There are many LWRs which have been operated for more than 20 years in Japan and it is expected that technique corresponding to aging plants are necessary established for safety operation in LWRs. A lot of troubles related to SCC are reported and many investigations are concerned with SCC mechanism and technical evaluation. In this paper, those research data were collected as possible widely and reviewed systematically. Current circumstances concerned with SCC in LWRs were reviewed specifically as follows: SCC incidents, SCC evaluation methods for crack initiation and propagation, the investigations concerned with SCC mechanism and monitoring technique for corrosive environment. Influences with reactor types (BWR, PWR), materials (stainless steels, Ni alloys) and SCC evaluating methods (laboratories and actual plants) were summarized as graphs and tables easy to understand in common/difference points concerned with SCC. From these arranged results, future themes were considered and remarked SCC phenomenon was summarized in actual plants.