IMPACT BEHAVIOR OF 2 LOW-ACTIVATION STEELS AFTER IRRADIATION TO SIMILAR-TO-67 DPA AT 430-DEGREES-C

Miniature CVN specimens of four martensitic steels, GA3X, F82H, GA4X a nd HT9, have been impact tested following irradiation at 430 degrees C to 67 dpa. Comparison of the results with those obtained previously a t lower doses indicates that the GA3X and F82H alloys, two primary can didate low activation alloys, exhibit similar behavior following irrad iation at 430 degrees C to N67 dpa and at 370 degrees C to similar to 15 dpa. Virtually no shift in either ductile to brittle transition tem perature (DBTT) or upper shelf energy (USE) was observed in the F82H a lloy at 67 dpa for either notched or precracked specimens. This absenc e of a shift in DBTT and USE in F82H compares with a slight increase i n DBTT and a slight decrease in USE for GA3X, and much larger degradat ion in both properties in GA4X and HT9. The shifts in DBTT and USE obs erved in both GA4X and HT9 were smaller after irradiation at 430 degre es C to similar to 67 dpa than after irradiation at 370 degrees C to s imilar to 15 dpa. (C) 1998 Elsevier Science B.V. All rights reserved.