Fatigue Growth in Piping and RPV Steels in Simulated BWR Water Environment,

摘要

Report summarizes results of experimental testing program on establishing fatigue crack growth behavior of several commercial pressure vessel and piping steels typically used in LWRs. Results show that crack growth rates increase in the BWR water environment by decreasing the frequency of cyclic loading or increasing the mean load present during the load cycle. However,in pressure vessel alloy steel these effects are moderated by transverse secondary microcracking,which is a manifestation of a crack tip chemistry interaction for the environment/material pair. This behavior is consistent with previous GE experience with in-service cracking in pressure vessel components,wherein analytic projections of cracking rates always tend to overpredict crack depths when compared to actual field observations.