An extended finite element method-based representative model for primary water stress corrosion cracking of a control rod driving mechanism penetration nozzle

摘要

Primary water stress corrosion cracking incidents have been reported in nuclear reactors over the past several decades. Garud et al developed an empirical equation to express primary water stress corrosion cracking (PWSCC) initiation time by using experimental data. This strain rate damage model has been used in multiple simulation studies. Some of these studies used the extended finite element method (XFEM) to simulate the PWSCC propagation in Alloy 600. However, several studies showed that the accuracy of XFEM depends on the mesh quality. Different mesh qualities can change the heat flux of a welding procedure, leading to different weld residual stresses. We performed a parametric study on PWSCC initiation and propagation of a control rod driving mechanism by using different mesh qualities. The major variables explored here are number of elements per bead, number of circumferential elements, and number of weld beads. Finally, an XFEM-based representative model was suggested for PWSCC initiation and propagation simulation.