Modeling of Chemical Transition of Nitrate Accompanied with Corrosion of Carbon Steel under Alkaline Conditions

Abstract

Interaction between carbon steel and nitrate was modeled using the mixed potential concept. Carbon steel was selected as an example of metal components in the repository of radioactive wastes. The nitrate reduction accompanied with the corrosion of carbon steel was modeled as a reaction series of NO₃^– → NO₂^– → NH₃. The sum of the current of the reaction series of NO₃^– → NO₂^– → NH₃ and that of water reduction was assumed to be balanced with the oxidation current of carbon steel. The input parameters for this kinetic model were determined by electrochemical measurements and immersion tests. The results of the immersion tests can be interpreted by the analyses of the model.