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

Abstract 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 T 0 for each irradiation temperature and dose and compared to unirradiated T 0 . Current fracture toughness shifts compared with T 0 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.