Effectiveness of Excavate and Weld Repair on a Large Diameter Piping Dissimilar Metal Weld by Finite Element Analysis Available to Purchase

Finite element weld residual stress analyses are performed to investigate the effectiveness of a newly proposed repair option for primary water stress corrosion cracking (PWSCC) in dissimilar metal welds in PWRs: Excavate and Weld Repair (EWR). Analyses are performed on a 30″ (762mm) outside diameter (OD) and 3″ (76mm) thick stainless steel pipe connected to a low alloy steel nozzle with a dissimilar metal weld (DMW). Eight EWR cases are analyzed to evaluate the sensitivities in weld residual stresses due to variations in the width and depth of the EWR, including cases with and without a thin weld cap on top of the DMW. The results demonstrate that a wide EWR that extends beyond the original width of the DMW provides the maximum residual stress benefits to the DMW, in terms of reducing the as-welded residual stresses. It is also found that the presence of the weld cap yields only marginal residual stress benefits.