Mitigation of stress corrosion cracking through suppression of radiolytic oxygen

Intergranular Stress Corrosion Cracking (IGSCC) in the weld heat affected zones of austenitic stainless steel piping has adversely affected the availability of Boiling Water Reactors. A promising method of mitigating IGSCC susceptibility of pipe welds involves suppression of coolant oxygen by addition of hydrogen gas to the plant's feedwater. The hydrogen recombines with the radiolytically produced oxygen and reduces the chemical driving force for IGSCC below the threshold value. A series of studies were performed both in-reactor and in the laboratory to demonstrate that this modified environment not only inhibits IGSCC of sensitized stainless steel, but also could be economically and technically accomplished in an operating reactor. The results of these studies demonstrates that this technique has a high probability of success