Analysis for crack growth regularities in the nozzle-cylinder intersection area of Reactor Pressure Vessel

In this study, linear elastic fracture mechanic analysis for Reactor Pressure Vessel (RPV) of Westinghouse AP1000 is presented to compute stress intensity factor (SIF) of nodes on the crack front. Then crack propagation analysis is carried out under pressure loading condition and cracks are postulated in the in-let nozzle-cylinder intersection area which is also the highest stress concentration area of the RPV. The SIFs of the surface nozzle corner cracks are numerically computed under different loading conditions, and the crack shape evolving regularities under design loading condition are presented, thus providing a useful tool for fracture mechanic design of RPV. The analysis reveals that the 1/4 wall thickness corner crack of in-let nozzle do not endanger the safety of RPV under design condition. The crack has a larger propagation rate at pressure vessel shell than that at the in-let nozzle.