PROCESS FOR CALCULATING THE TRANSITION TEMPERATURE CURVE OF IRRADIATED LOW-ALLOY REACTOR PRESSURE VESSEL STEEL

摘要

The invention relates to a process for calculating the transition temperature curve of irradiated low-alloy reactor pressure vessel steel for the radiant temperature range from 250 to 320 °C. To this end the instrumented notched bar impact bending test is performed on unirradiated samples of the pressure vessel steel. Here, the transition temperature curves for the partial energy, the hydrogen and oxygen concentrations in the unirradiated steel samples and their metallographic structure are determined. The transition temperature curve is calculated from these data using a mathematical process. In contrast to the purely empirically statistical prior art calculation of the rise in transition temperature, the process described is based on proven defect mechanisms and their behaviour in reactor irradiation. This results in a substantially lower risk in predicting radiation embrittlement than heretofore.