Review on crack growth driving force at the tip of stress corrosion cracking in the safe end dissimilar metal welded joint

Abstract

The welded structural materials of nuclear power plants (NPPs) are susceptible to environmentally-assisted cracking (EAC), represented by stress corrosion cracking (SCC), in prolonged high-temperature and high-pressure water environments, posing a significant threat to plant safety. This study aims to provide a critical review for the crack growth driving force at the tip of SCC in the safe end dissimilar metal welded joint (DMWJ) of NPPs. Firstly, SCC’s background, importance, and current research status are introduced. Secondly, a review and analysis are conducted on SCC’s initiation and growth stages, focusing on experimental methods, predictive models of crack growth rate, crack tip mechanical states, and influencing factors, clarifying the main achievements and challenges in current experimental and theoretical research. Finally, a method to mitigate crack tip driving force is proposed, followed by an in-depth analysis from a mechanical perspective on the relationship between crack growth driving force and crack growth resistance, highlighting future research trends. This review provides theoretical references and technical support for addressing the issue of SCC in welded structural materials of NPP primary circuit.