Fracture toughness characterization of JLF-1 steel after irradiation in HFIR to 5 dpa

Fracture toughness specimens of the ferritic–martensitic steel JLF-1 were investigated before and after irradiation at two different temperatures in the High Flux Isotope Reactor. Small (12.5 mm in diameter with thickness of 4.6 mm) disk-shaped compact tension specimens were irradiated at average temperatures of ∼250 °C and 377 °C to ∼4 dpa. Small, 3.33 × 3.33 × 25 mm, pre-cracked Charpy specimens were irradiated at ∼300 °C and 500 °C to 5 dpa. Transition fracture toughness was evaluated in terms of the reference temperature T0 for each irradiation temperature and dose and compared to unirradiated T0. Current fracture toughness shifts compared with T0 shifts of F82H and 9Cr2WVTa steels irradiated at similar conditions. The present results show that JLF-1, F82H, and 9Cr–2WVTa steels have very similar resistance to radiation embrittlement after doses of 4–5 dpa in the temperature range from 250 °C to 500 °C.