A Study of Part Through Cracks in a Reactor Beltline Subjected to Thermal Shock

Abstract

A problem which has received considerable attention in the past few years is the analysis of a cracked reactor beltline region which is subjected to a thermal shock loading condition. This attention has resulted in many techniques for estimating the Stress Intensity Factor (K_I) distributions along the front of part through cracks for this problem. The purpose of the study presented herein is to utilize some of these more recent developments for a linear elastic analysis of hypothetical elliptical surface cracks subjected to a time-varying non-uniform stress distribution which results from a thermal shock loading. The problem is further complicated because the initial crack is assumed to be in a weld region with the possibility of extending into a base material region with different material properties. A technique which is based on linear elastic fracture mechanics is chosen to predict K_I distributions for the geometry and loading employed. In order to gain confidence in the solution, it is compared with other available analytical and numerical solutions from the literature. It is then used to predict crack extension and subsequent arrest with consideration given to the varying material parameters present.