Investigation of crack initiation behavior using pre-irradiated austenitic stainless steel at JMTR

Tsukada, Takashi ; Ugachi, Hirokazu ; Kaji, Yoshiyuki  ; Miwa, Yukio; Nakano, Junichi; Matsui, Yoshinori ; Endo, Shinya; Kato, Yoshiaki; Nagata, Nobuaki*; Dozaki, Koji*; Takiguchi, Hideki*

Irradiation Assisted Stress Corrosion Cracking (IASCC) has been regarded in recent years as the matter that is related to the reliability for core components of LWRs. The in-pile IASCC initiation tests were performed using of uniaxial constant load specimens pre-irradiated to about 510n/m and 110n/m at JMTR under the simulated BWR core condition. From the results of in-pile and out-of-pile tests of the irradiated specimens, we confirmed that any remarkable acceleration effect of synergy of neutron/ radiation and stress/water environment on SCC initiation results was not observed under the test condition of this study. On the surface of in-pile test specimen, a micro crack was observed on the surface of specimen, and it was considered to be an initiation of SCC besed on the results of out-of-pile experiments.