| Abstract |
| Abstract: Sulfur-containing species are one of the major impurities in the secondary side of PWR (Pressurized Water Reactor) nuclear power plants. These come from feed water, resin resources, cooling water leakage, and condenser leakage. In the operating conditions of a steam generator, SO4 2. ions can be reduced to S2., S2O3 2., S4O6 2. by hydrazine. This work focused on stress corrosion cracking (SCC) of mill annealed, sensitized, and thermally treated Alloy 600 in a Na2S4O6 solution. Analysis of carbide distribution, intergranular corrosion tests, including an electrochemical method, and electrochemical noise measurement during an SCC test were performed to determine SCC susceptibility of Alloy 600. Alloy 600 MA did not reveal SCC but Alloy 600 SE+ and Alloy 600 TT showed severe IGSCC. Sensitization and thermal treatment to Alloy 600 MA degraded the intergranular corrosion resistance and thus induced intergranular stress corrosion cracking in the Na2S4O6 solution and its SCC mechanism seems to be a pre-existing active path model. |
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| Key Words |
| Metals, Annealing, SCC, Electrochemistry, optical microscopy |
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