Tensile and Charpy impact properties of EUROFER97-3 and three RAFM steels after neutron irradiation at 330 ºC and 540 ºC to damage doses of 19-24 dpa

The reduced-activation ferritic–martensitic (RAFM) steels EUROFER97-3 subjected to two heat treatments (EUROFER97-3_980/780 and EUROFER97-3_1100/700), F82H, as well the experimental heats M474, and L664B were irradiated in the BOR-60 fast reactor at temperatures of 330 °C and 540 °C, with damage doses ranging from 19.2 to 23.8 dpa. The results for all steels revealed a significant impact of irradiation temperature on tensile properties. Irradiation at 330 °C led to strong hardening and a pronounced reduction in uniform elongation, whereas irradiation at 540 °C resulted in practically no changes in tensile properties. In addition, a significant decrease in the upper shelf energy (USE) and a large shift in the ductile–brittle transition temperature (DBTT) was observed after irradiation of EUROFER97-3 with both heat treatments at 330 °C, while no significant changes in Charpy impact properties after irradiation at 540 °C were detected. In essence, irradiation at 540 °C caused only minor changes in the USE and DBTT of all studied RAFM steels compared with the unirradiated condition.