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 plant pressure vessel made of CrMoV steel. With precracked specimens the J-value at the onset of brittle fracture was determined as a function of 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 fracture mechanical specimens both for the irradiated and non-irradiated material state are compared using a statistical brittle fracture model.