Reirradiation Response Rate of a High-Copper Reactor Pressure Vessel Weld

The Charpy impact response of reirradiated Heavy-Section Steel Irradiation (HSSI) Program Weld 73W has been determined at three fluence levels. The Charpy specimens had previously been irradiated at 288 C to 1.8 x 10{sup 19} cm{sup -2} (E > 1 MeV) and annealed at 454 C for 168 h. The results show that the change in the 41-J Charpy energy level transition temperature (OTT{sub 41-J}) of the reirradiated specimens is slightly higher than predicted by the vertical shift method, but significantly less than predicted by the lateral shift method. Previous results have also shown that the upper-shelf energy (USE) over-recovers as a consequence of annealing, which may explain why the USE value after a significant amount of reirradiation is approximately equal to the USE value in the unirradiated condition.