Bend-fatigue properties of JPCA and Alloy800H specimens irradiated in a spallation environment

To evaluate the lifetime of the beam window of an accelerator-driven transmutation system (ADS) and spallation neutron source, post irradiation examination (PIE) of the STIP (SINQ target irradiation program, SINQ; Swiss spallation neutron source) specimens has been carried out. The specimens tested in this study were made from the austenitic steel JPCA (Japan Primary Candidate Alloy) and high-Ni steel Alloy800H. The specimens were irradiated at SINQ Target 4 (STIP-II) with high-energy protons and spallation neutrons. The irradiation conditions were as follows: the proton energy was 580MeV, irradiation temperatures ranged from 120 to 350°C and displacement damage levels ranged from 7.0 to 19.3dpa. Bend-fatigue tests were performed in air at room temperature under deflection control mode. The wave form of the control signal was a sine curve with a frequency of 26Hz. Fracture surface observation after the tests was done by SEM.