Modeling of weld residual stresses in core shroud structures

This paper presents a computational model to predict residual stresses in a girth weld (H4) of a BWR core shroud. The H4 weld is a multi-pass submerge d-are weld that joins two type 304 austenitic stainless steel cylinders. An axisymmetric solid element model was used to characterize the detailed evo lution of residual stresses in the H4 weld. In the analysis, a series of ad vanced weld modeling techniques were used to address some specific welding- related issues, such as material melting/re-melting and history annihilatio n. In addition, a 3-D shell element analysis was performed to quantify spec imen removal effects on residual stress measurements based on a sub-structu ral specimen from a core shroud. The predicted residual stresses in the H4 weld were used as the crack driving force for the subsequent analysis of st ress corrosion cracking in the H4 weld. The crack growth behavior was inves tigated using an advanced finite element alternating method (FEAM). Stress intensity factors were calculated for both axisymmetric circumferential (36 0 degrees) and circumferential surface cracks. The analysis results obtaine d from these studies shed light on the residual stress characteristics in c ore shroud weldments and the effects of residual stresses on stress corrosi on cracking behavior. (C) 2000 Elsevier Science S.A. All rights reserved.