In an effort to shed light on accuracy and reliability of finite element (FE) weld modeling outputs, the U.S. Nuclear Regulatory Commission (NRC) and the Electric Power Research Institute (EPRI) have been engaged in a program of cooperative research on weld residual stress (WRS) prediction. The current work presents numerical FE simulation of the WRS in a pressurizer surge nozzle full-scale mockup (Phase 2b), as a part of the broader NRC/EPRI program. Sequentially-coupled, thermo-mechanical FE analysis was performed, whereby the numerical solution from the thermal analysis was used as an input in the mechanical analysis. The thermal analysis made use of a dedicated weld modeling tool to accurately calibrate an ellipsoidal Gaussian volumetric heat source. The subsequent mechanical analysis utilized the isotropic and nonlinear kinematic hardening constitutive models to capture cyclic response of the material upon welding. The modeling results were then validated using a number of measurement techniques (deep hole drilling, contour method, slitting, and biaxial mapping). In addition, an effect of the interpass temperature (i.e. 24.5 °C, 150 °C, and 260 °C) on the final prediction of WRS is discussed.

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