Corrosion estimation of stainless steel in nitric acid solution using cellular automata intergranular corrosion model

Igarashi, Takahiro  ; Komatsu, Atsushi ; Irisawa, Eriko ; Kato, Chiaki   

Since high-concentration boiling nitric acid with oxidizing metal ions is used in reprocessing process of spent nuclear fuel, it is quite severe corrosive environment for stainless steel, and cause intergranular corrosion. For long-term stable and safety operation of reprocessing and prediction of life of structure, it is necessary to predict the amount of corrosion due to intergranular corrosion over several decades. However, since the error in the estimation by the amount of long-term corrosion from the results of conventional corrosion tests of several days is large, improvement of accuracy has been one of the problems. In this study, intergranular corrosion behavior was predicted using the cellular automatic intergranular corrosion model with the parameters from measured data of short-time corrosion test, and the prediction of long-term corrosion behavior was evaluated by comparing with the results of long-term mockup corrosion test. These results showed that the amount of corrosion could be predicted more accurately from a short-term corrosion test.