Mechanical properties of JPCA and Alloy800H irradiated up to 19 dpa at SINQ target4

Saito, Shigeru   ; Hamaguchi, Dai; Kikuchi, Kenji*; Usami, Koji; Endo, Shinya; Ono, Katsuto; Matsui, Hiroki; Kawai, Masayoshi*; Yong, D.*

In several institutes, the research and development for an accelerator-driven transmutation system (ADS) to transmute minor actinide (MA) have been progressed. To evaluate lifetime of the beam window, post irradiation examination (PIE) of the STIP (SINQ target irradiation program, SINQ; Swiss spallation neutron source) specimens was carried out at JAEA. The specimens were austenitic steels JPCA and Alloy800H. The irradiation conditions of the specimens irradiated at SINQ target 4 (STIP-II) were as follows: proton energy was 580 MeV, irradiation temperatures were ranged from 100 to 450C, and dpa were ranged from 6.5 to 19.5 dpa. All PIE works has been carried out at WASTEF and RFEF in Tokai Research and Development Center, JAEA. Tensile tests were performed in air at R.T., 250C and 350C. Fracture surface observation after the tests was done by SEM. Results of the tensile tests performed at R.T. indicate that irradiation hardening occurred with increasing displacement damage level up to 10 dpa. At higher doses, irradiation hardening seemed to tend to saturate. Degradation of ductility was bottomed around 10 dpa and specimens kept its ductility until 19.5 dpa. The most of specimens fractured in ductile manner, however, the specimens irradiated at the higher dose ( 19 dpa) and higher temperature ( 400C) showed partially intergranular morphology.