The Electrochemical Investigation of Dissolution of Nickel Ferrite in Aqueous Solutions

In a pressurized water reactor (PWR), the oxide layer formed on the surface of the reactor coolant system is generally known to be made of two different layers, a Fe rich (Fe₃O₄, NiFe₂O₄) external layer and a Cr rich (FeCr₂O₄, Cr₂O₃) inner layer. In this sturdy, we investigated the characteristics of dissolution to NiFe₂O₄ in HYBRID(HYdrazine Based metal Ion Reductive Decontamination) which was developed in KAERI used in reductive decontamination of the inner surface of PWR. HYBRID is consist of hydrazine, sulfuric acid and copper ion. We investigated the dissolution of NiFe_O when the hydrazine and copper sulfate added to the sulfuric acid solution. Potentiostatic electrochemical impedance spectroscopy (EIS) is a useful tool for the analysis of complex electrochemical systems [3]. We conducted the EIS for this study. From the analysis of EIS results, R₁, taken as equal to the rate of reductive dissolution of magnetite, decreased when N₂H₄ and Cu⁺ ion added. In practice HYBRID solution is used at 95 .deg. . However, experiment was carried out at room temperatures in this study.