The mechanism of localized in-pile corrosion of zirconium alloys, (III)

The electric charges to enhance the localized in-pile corrosion are estimat ed quantitatively by a model analogous to an electric circuit. The model is more detailed than that reported in the? previous papers. it is applied to the cases of a fuel cladding near platinum in the Halden experiments and a fuel channel near a control blade. As a result, respecting the electric ch arges to enhance the localized oxidation; both cases investigated in this w ork are explained quantitatively by the total amount of electric current, f rom all the localized electrochemical cells between the surface of zirconiu m oxide adjacent to and facing to bare and gounded metals such as platinum or stainless steel and its neighboring parts, introduced by the "beta-induc ed electric fields" on zirconium oxide. The electric potential of the electrochemical cell concerned decreases in t he course of oxidation, and therefore, the retardation of oxidation during the growth of the oxide film can be explained by the fact that the electric current by the above electrochemical cell becomes insufficient to enhance the localized oxidation.