A Probabilistic-Mechanistic Approach to Modeling Stress Corrosion Cracking Propagation in Alloy 600 Components with Applications

Abstract

Stress corrosion cracking (SCC) is a major degradation mechanism of Alloy 600 steam generator (SG) tubes composed of three main stages: crack incubation, crack initiation and crack propagation. Since SG tubes act as a barrier between the radioactive material and the atmosphere, SCC becomes a critical failure mechanism that jeopardizes safety and integrity. As such, this research proposes a probabilistic-mechanistic approach focused on modeling SCC propagation of Alloy 600 SG tubes with uncertainty. The approach is presented in two parts; the first is an empirical model and the second is a simulation process. To provide a background, this research provides an overview of SCC fundamentals, nuclear power generation and SGs, as well as specifics regarding SG tube degradation. Simulation of SCC on Alloy 600 SG tubes in primary water provided logical results. Future work in this research is also discussed at the end of this paper.