Electrochemical Studies of Steam Generator Tube Degradation in the Presence of Thiosulphate

Abstract

Sulphur species in oxidation states between S2− and S6+ are known to interfere with the protective oxide films that form on steam generator tubing materials. By assisting in the breakdown of passive films, intermediate oxidation state sulphur species can cause intergranular attack and pitting of steam generator tubing over a wide pH range. Intermediate oxidation state sulphur species have also been observed to induce stress corrosion cracking of sensitized Alloy 600 at low temperatures.