Evaluation of microstructure and residual stress on dissimilar welds of nuclear components

To perform a more realistic integrity evaluation for the dissimilar welds of NPP(Nuclear Power Plant) component, it is necessary to evaluate the microstructure and residual stress considering the actual welding process such as multi-pass welding and PWHT (Post Weld Heat Treatment). This paper proposes an integrated assessment methodology systematically developed for microstructure and residual stress on welds utilizing thermodynamics, diffusion theory, finite element method and validation experiments. And, the metallurgical microstructure and residual stress of the dissimilar weld on safety injection branch line nozzle are evaluated by application of this systematic methodology