Numerical Crack Growth Analysis in ICM Housing Using S-Version FEM

Abstract

It has been reported that stress corrosion cracking damaged in-core monitor housing, which occurred in weld heat-affected zone because of the existence of residual stress. So it is important to evaluate crack growth behavior with high accuracy. In this study, crack growth behavior in ICM Housing is estimated using S-version FEM (S-FEM), which allows generation of core finite model and the detailed mesh representing the crack independently. At First, axial, slant and circumferential surface crack are assumed at two locations where residual stress fields are different from each other. One is isotropic residual stress field, and another is circumferential residual stress field. It is shown that crack growth behaviors are different under different residual stress fields. Next, effect of the slit, which exists between ICM Housing and Pressure Vessel is evaluated. It is shown that the existences of slit increases stress intensity factors of growing surface crack. Finally S-FEM results are compared with those of Influence Function Method (IFM), which assumes that an elliptical crack shape exists in a plate. It is shown that IFM result is conservative than that of S-FEM.