Crack Propagation Analysis of Weld Overlay Structure for Pressurizer Nozzle Safety End

Based on the design loads of the pressurizer in nuclear power plants, this paper investigates the crack propagation induced by the fatigue and the stress corrosion of the design overlay weld structure in the pressurizer nozzle safety end. The crack propagation depth is obtained, and the safety assessment is carried out. At the end of the cycle, the maximum circumferential crack growth depth and axial crack growth depth in dissimilar metal weld zone are 0.4 × 10^-3 mm and 23.6 × 10^-3 mm, respectively, while the maximum circumferential crack growth depth and axial crack growth depth in stainless steel weld zone are 12.4 × 10^-3 mm and 0 mm. The results show that the crack propagation meets the design requirement. This analysis can provide a reference for the overlay weld structure design and evaluation of the pressurizer nozzle safety end. (authors)