Effect of pH and hydrogen peroxide in radioactive water on the passivity of 1018 carbon steel

Abstract

Tritiated water, containing radiolytic hydrogen peroxide, was used in this work. In the vessels of the plant for the reprocessing of this water, the pH necessarily has different values, and consequently, we used pH values of 5–6 and 13 in our studies. The corrosion potential of the carbon steel, as well as the redox potential of the tritiated water taken immediately from a closed storage vessel with a pressure of 5×10⁵ Pa radiolytic gas, are in the passive-transpassive potentials. Immediately after removal from storage, the concentration of hydrogen peroxide decreases rapidly and the potentials are in the prepassive region. This will subsequently reveal the importance of the concentration of radiolytic hydrogen peroxide in passivity and corrosion. During the corrosion and passivity tests, the thickness of the oxide layer with H₂O₂ was determined.