Prediction of Weld Residual Stress in a PWR Pressurizer Surge Nozzle: A Proposed Fast Computational 3D Analysis Method and Influence of Its Heat Source Model

Primary water stress corrosion cracking (PWSCC) generated in dissimilar metal welds is one of the safety issues in ageing pressurized water reactor piping systems. It is well known that analysis accuracy of cracking propagation due to PWSCC depends on welding residual stress conditions. The U.S. Nuclear Regulatory Commission carried out an international round robin program for welding residual stress analysis validation to evaluate the accuracy and uncertainty quantitatively. In this study, participation results in the round robin program were reported. The three-dimensional analysis based on a fast weld simulation using the Iterative Substructure Method was clarified to provide accurate results in a high-speed computation. Furthermore, the influence of different heat source models on analysis results was investigated. It was demonstrated that the residual stress and distortion calculated using the moving heat source model were more accurate.