SCC亀裂進展速度の定式化が亀裂進展特性に及ぼす影響

抄録

This paper describes the examination on a crack growth rate formula used for planning the inspection timing in the individual inspection of the rules on Fitness-For-Service (FFS) of the Japan Society of Mechanical Engineers (JSME). The inspection timing of the individual inspection is set to keep structural integrity while predicting the progress of degradation. For example, the inspection timing of the piping in primary loop recirculation system (PLR) that may generate stress corrosion cracking (SCC) is determined based on the SCC crack growth prediction. The effect of the formulation of the SCC crack growth rate on the SCC crack growth characteristic was examined. Crack growth behavior used two formulae, the formulation based on the power law conventionally used in the rules on FFS and the formulation based on the mechanistic theory, are compared. Consequently, there is no big difference between the two, and the formulation of the power law is recommended to determine the inspection timing in the individual inspection of PLR piping from its convenience and conservatism.