High-temperature and high-pressure SCC device for synchrotron radiation diffraction experiments and application using an austenitic stainless steel

Yamamoto, Atsushi*; Nakahigashi, Shigeo*; Terasawa, Michitaka*; Mitamura, Toru*; Akiniwa, Yoshiaki*; Yamada, Takayuki*; Liu, L.*; Shobu, Takahisa  ; Tsubakino, Harushige*

Suppressing the stress corrosion cracking (SCC) by reducing the carbon content in austenitic stainless steels is apparently not effective on core shrouds used in boiling water reactors in Japan: trans-granular cracking was found in the shrouds. To clarify the mechanism of the cracking, in situ stress measurements on specimens under stretched conditions in hot water have been attempted in the present study. In situ experiments have been carried out at SPring-8. The SUS316L steel specimen was placed in the in situ device. Sapphire windows were used for the light path in the device. A sufficient diffracted beam intensity was obtained through two sapphire windows and water. The side-inclination method was used for measuring the stress exerted on the specimen. A 2 sin plot showed that a tensile stress was induced. The measured stress value is considered to be the summation of stresses owing to pre-straining, in situ loading and residual stress owing to surface grinding.