Shear punch testing of candidate reactor materials after irradiation in fast reactors and spallation environments

Ferritic/martensitic steels and nickel-base superalloys are potential materials for use in spallation targets and fusion and fast reactors. To investigate the effects of irradiation on these materials, tests were performed after irradiation in the high energy proton beam at the Paul Scherrer Institute (SINQ Target Irradiation Program (STIP), 570 MeV), as well on specimens obtained from a driver duct irradiated in the Fast Flux Test Facility (FFTF). Dose accumulations were up to 18 dpa for STIP irradiations (at 147–406 °C) and up to 155 dpa in FFTF (at 383–505 °C). The helium/dpa ratios ranged from 0.2 to 80 appm/dpa. Mechanical testing was performed at 25 °C. Increases in shear yield and shear maximum stress with increasing dose mirrored the results observed from companion tensile tests.