Brittle Strength of the VVER Pressure Vessel Steels under Operation Conditions
Abstract
Complex of mechanical tests and fractographic studies of various sample types were conducted for VVER pressure vessel steels. The brittle fracture sources (origins) were revealed: “non-metallic inclusions” and “structural boundaries”. The computational-experimental technique for evaluation of the local normal stress parameter that characterizes strength of the origin was performed. Values of the local normal stress
for the “structural boundary” origin type was demonstrated to be decreasing after thermal and radiation embrittlement due to decreasing in cohesive strength of grain boundaries by virtue of thermo- and radiation- stimulated diffusion of the impurities to grains boundaries.
Keywords: reactor pressure vessel, fractography, local normal stress, brittle fracture, origin
References
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