Stress corrosion cracking (SCC) in the weld joints of Ni-base alloys in BWR plants has been reported and is one of the most important issues in the structural integrity assessment of the Ni-base alloy weld components. In the structural integrity evaluation, based on the fracture mechanics, the modeling of the crack shape is important. In this study, stress intensity factor K of axial surface cracks with elliptical and trapezoidal shapes in the weld metal in the BWR shroud support joints were evaluated by FEM analysis in order to examine the applicability of elliptical surface crack model that is generally adopted in the codes and standards to the stress intensity factor evaluation of trapezoidal surface crack.
