Role of Zn injection on mitigating stress corrosion cracking initiation of Alloy 182 weld metal in simulated light water reactor environment

The stress corrosion cracking (SCC) behaviour of nickel-based weld metal Alloy 182 was studied in simulated light water reactor environments with or without zinc (Zn) addition. Accelerated SCC initiation tests with flat tapered tensile specimens, as well as SCC initiation and short crack growth tests with compact tension specimens revealed that Zn injection is able to effectively mitigate SCC. Even the lowest tested Zn concentration of 15 ppb seems to be enough to achieve a significant mitigation effect on SCC initiation and short crack growth. This beneficial effect may be related to the modified surface oxide film by Zn incorporation.