Three-dimensional finite element simulation of welding residual stress in RPV with two J-groove welds

A mockup-to-product strategy was proposed to in-vestigate the multipass welding residual stress in large nuclear structures. First, a mockup was manufactured and the temper-ature cycle during welding and residual stress after welding were obtained; then the finite element (FE) simulation of welding temperature field and stress field for the mockup was performed using experimental results to calibrate the FE model and algorithms; in addition, a series of simulations on the mockup were undertaken to find the optimal model and efficient simulation methods; finally, the optimized model and efficient methods were adopted to simulate the welding resid-ual stress of products. Using the proposed approach, the welding residual stress in the nuclear reactor pressure vessel (RPV) head with two J-type welds was efficiently simulated, and the stress interaction between the two J-type welds were studied. Research results suggest that the mockup-to-product method can be applied to efficient numerical simulation of residual stress in large nuclear welded structures, and simula-tion results indicate the stress interaction effect between two J-type welds in AP1000 RPV head is not significant.