COMPARISON OF CHARPY-V AND J-INTEGRAL TRANSITION-TEMPERATURE SHIFTS IN CRMOV PRESSURE-VESSEL STEELS

Both Charpy - V and precracked Charpy -size specimens were included in the original surveillance programme of the Loviisa nuclear power plan t pressure vessel made of CrMoV steel. With precracked specimens the J -value at the onset of brittle fracture was determined as a function o f temperature and irradiation dose. The irradiation induced transition temperature shifts measured with Charpy-V and precracked three-point bend specimens are correlated by using indexed temperature values. The shapes of brittle fracture transition curves measured with the fractu re mechanical specimens both for the irradiated and nonirradiated mate rial state are compared using a statistical brittle fracture model.