Impact behavior of two low activation steels after irradiation to ∼67 dpa at 430°C

Abstract

Miniature CVN specimens of four martensitic steels, GA3X, F82H, GA4X and HT9, have been impact tested following irradiation at 430°C to 67 dpa. Comparison of the results with those obtained previously at lower doses indicates that the GA3X and F82H alloys, two primary candidate low activation alloys, exhibit similar behavior following irradiation at 430°C to ∼67 dpa and at 370°C to ∼15 dpa. Virtually no shift in either ductile to brittle transition temperature (DBTT) or upper shelf energy (USE) was observed in the F82H alloy at 67 dpa for either notched or precracked specimens. This absence of a shift in DBTT and USE in F82H compares with a slight increase in DBTT and a slight decrease in USE for GA3X, and much larger degradation in both properties in GA4X and HT9. The shifts in DBTT and USE observed in both GA4X and HT9 were smaller after irradiation at 430°C to ∼67 dpa than after irradiation at 370°C to ∼15 dpa.