Fracture analysis of the set-in nozzle of a PWR reactor pressure vessel – Part 1: Determination of critical crack

•The SIFs of the corner cracks are provided under accidental conditions of the PWR.•The material’s embrittlement due to nuclear environment is presented.•The critical crack depth at the nozzle-cylinder intersection is determined. In this study, fracture mechanics analysis of the set-in nozzle of a reactor pressure vessel (RPV) is being presented. The selected RPV belongs to a 300MW pressurized water reactor (PWR). For the purpose, a wide range of elliptical surface cracks was analyzed at the nozzle-cylinder intersection under two accidental conditions of the reactor: small-break loss of coolant accident (SB-LOCA), and Rancho-Seco transient (RST). It has been demonstrated that at the location being investigated ‘a=0.05t’ is the critical crack depth; where ‘a’ is the depth/minor axis of the crack and ‘t’ is the thickness of the wall.