Ni-Doped F82H to Investigate He Effects in HFIR Irradiation

Nickel-doped F82H alloys have been fabricated to simulate He production due to fusion neutrons in fission reactor irradiation. 1.2Ni and 1.4Ni alloys were tempered at 750°C without re-austenitisation. Expected He production in 1.4% Ni alloy irradiated in HFIR target position is about 400 appm at 40 dpa. Results of tensile and Charpy impact tests of these alloys show that their mechanical properties are similar to those of original F82H, although 0.2% proof stresses of Ni-doped alloys were 50 Mpa smaller than that of F82H. Small amount of two isotope tailored alloys including 1.4wt% Ni are also prepared using 58Ni and 60Ni. Chemical analyses and Charpy impact tests of the mock-up heat suggest that the fabrication of these small heats was successful.