The studies of irradiation assisted stress corrosion cracking on reactor internals stainless steel under Xe irradiation

Specimens of Chinese domestic reactor internals stainless steel were irradiated with 6 MeV Xe ions for three peak displacement damage of 2, 7 and 15 dpa at room temperature. The slow strain rate tests (SSRT), grazing incidence X-ray diffraction (GIXRD) and nano-indentation tests were carried out to study the IASCC properties, phase transition and nano-hardness variations. The SSRT results indicate that the IASCC susceptibility increases with irradiation damage. Ion irradiation accelerates the stress corrosion cracking (SCC). A new ferrite phase diffraction peak of α(1 1 0) after irradiated to 7 dpa and another two α phase of α(2 0 0) and α(2 1 1) after irradiated to 15 dpa were observed by GIXRD, which may be due to localized deformation. A similar trend of irradiation hardening and IASCC susceptibility was observed, which suggests an essential connection between them.