Modeling of chemical transition of nitrate accompanied with corrosion of carbon steel under alkaline conditions

Honda, Akira; Masuda, Kaoru*; Imakita, Tsuyoshi*; Kato, Osamu*; Nishimura, Tsutomu*

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 waste. The nitrate reduction accompanied by the corrosion of carbon steel was modeled as a reaction series such as nitrate - nitrite - ammonia. The sum of the current of the reaction series of nitrate - nitrite - ammonia and that of water reduction was assumed to balance with the corrosion current of carbon steel. The input parameters for this kinetic model were determined by electrochemical measurement and immersion test. The results of the immersion test can be interpreted by the analyses of the model.