Irradiation effects on aging of pressure vessel steels

A comprehensive approach is described for predicting in-service embrittlement of pressure vessel steels. The approach combines physical models of the irradiation damage with statistical analyses of test and power reactor data and calibration against data from fundamental experiments in which both mechanical property and microstructural changes are evaluated. The resulting model is able to self-consistently rationalize a wide array of microstructural and mechanical property data for commercial pressure vessel steels as well as model alloys. The implications of these results to other aging-related degradation problems are discussed. When combined with advanced techniques to characterize properties, described in a companion paper, this approach promises significant improvements in the accuracy of forecasting pressure vessel life