Comparison of Fracture Toughness of Irradiated Reactor Vessel Welds - Predicted by ASTM E 900 and Measured

摘要

Recently, a new predictive model has been developed by the NRC and is being implemented in ASTM Standard E 900, that addresses radiation-induced embrittlement of ferritic steels. The model is based on extensive Charpy impact energy data of irradiated reactor vessel steels obtained from surveillance programs. The final application of this nwe method is to predict fracture toughness of irradiated materials to determine pressure-temperature curves for nuclear power plant operation and RT_PTS values in compliance with the current regulatory rules for the nuclear-utility industry. In this paper, the predicted fracture toughness of irradiated reactor vessel welds is compared with that of irradiated material. The degree of conservatism in the Charpy impact energy based predictive model is assessed by comparison with the actual fracture toughness of irradiated materials.