A model for PWR pressure vessel embrittlement

A model has recently been described for the interpretation of yield stress monitoring data from surveillance samples of pressure vessel steels exposed in Magnox reactors. The model assumes embrittlement to arise from the combined effects of damage clusters and copper precipitates. The formation of the precipitates may be enhanced by irradiation. In this report, the Magnox model is extended and adapted to enable an interpretation of data from PWR pressure vessel steels to be made. The model is then used to estimate the changes in properties that will occur throughout the pressure vessel wall in the beltline region of the proposed UK PWR. It is found that the model successfully accounts for the trends of PWR surveillance and MTR embrittlement data with exposure and copper content. (U.K.)