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

A beam window of a spallation target will be subjected to proton/neutron irradiation, pressure wave and thermal stresses accompanied by high-energy proton beam injection. To obtain irradiation data, the SINQ target irradiation program (STIP) was initiated in 1996 at PSI. JAERI takes part in STIP and conducted the post-irradiation examination of JPCA, 316F. Irradiation conditions of JAERI specimens were as follows: proton energy was 590 MeV. Irradiation temperature ranged from 135 to 360 °C and irradiation dose from 6.3 to 12.5 dpa. The fatigue life of irradiated specimens is almost the same as that of unirradiated specimens. On the other hand, fracture surfaces varied with irradiation conditions. Specimens irradiated at low temperature fractured in a ductile manner. However, intergranular fractured surfaces were observed for 316F irradiated up to 12.5 dpa at 360 °C.