J-r curve characterization of a 533-b weld metal with irradiation and postirradiation annealing

The potential benefit of a cyclic postirradiation annealing and reirradiation procedure is investigated as a means of mitigating the progressive embrittlement with irradiation of commercial rector vessel steels. Material characterizations include two representative A533-B weld deposits, each containing a high copper impurity level which is associated with a high sensitivity to radiation. Assessments made on the basis of the J-R curve and tearing modulus show that intermediate annealing at 399 degree C has resulted in a recovery of half of the toughness which was lost with the first irradiation. Subsequent reirradiations, to a total fluence of twice that of the initial irradiation, have resulted in no additional loss in toughness, thereby suggesting a concept of embrittlement arrest associated with the annealing procedure