Bend-fatigue properties of 590 MeV proton irradiated JPCA and 316F SS

Saito, Shigeru   ; Kikuchi, Kenji; Usami, Koji; Ishikawa, Akiyoshi; Nishino, Yasuharu ; Kawai, Masayoshi*; Dai, Y.*

In several institutes, research and development for an accelerator-driven spallation neutron source have been progressed. A beam window of a target will be subjected to proton/neutron irradiation, pressure wave and thermal stresses accompanied by high-energy proton beam injection. To obtain the irradiation data, the SINQ target irradiation program (STIP) at Paul Scherrer Institute (PSI) has been progressing. JAERI takes part in STIP and shares the PIE work. The STIP specimens are very small so that we developed a new fatigue-testing machine with ceramic piezoelectric actuator. The results showed that the numbers of cycles to failure (Nf) on the irradiated specimens were less than that of unirradiated specimens. Dpa dependence of Nf was not clearly seen in the irradiation conditions. On the other hand, fracture surface varied with irradiation conditions. Specimens irradiated at low temperature fractured in ductile manner. However, interglanular fractured surface was observed for 316F SS irradiated up to 12.5 dpa at 360C.