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Igarashi, Takahiro; Komatsu, Atsushi; Motooka, Takafumi; Ueno, Fumiyoshi; Yamamoto, Masahiro
Proceedings of 19th International Corrosion Congress (19th ICC) (CD-ROM), 7 Pages, 2014/11
We constructed three dimensional computational model using cellular automata method to simulate the intergranular corrosion propagation of stainless steel. By the simulation using the model, we verified the relationship between surface roughness during corrosion and dispersion of dissolution rate of grain boundaries (GB). The relationship was investigated by the simulation applying constant dissolution rate for GB cells and distributed dissolution rate of GB cells. Our simulations revealed that the surface roughness calculated by the model adopted distributed dissolution rates of GBs was greater than that adopted constant dissolution rates of GBs. The cross-sectional images obtained by our simulation were comparable with that obtained by corrosion tests. These results indicate that the surface roughness during corrosion relates the distribution of corrosion rate.
-ray irradiation on corrosion of low alloy steel in neutral waterYamamoto, Masahiro; Nakano, Junichi; Komatsu, Atsushi; Sato, Tomonori; Tsukada, Takashi
Proceedings of 19th International Corrosion Congress (19th ICC) (CD-ROM), 6 Pages, 2014/11
Corrosion protection of RPV and PCV is an important issue for the long term maintenance until the end of the decommissioning procedures. One of the uncertain factors for the issue is an effect of radioactivity on corrosion of LAS and CS. Corrosion tests using LAS and CS were conducted in -rays irradiated condition. Oxygen and hydrogen peroxide concentrations in the water were measured after the tests. Corrosion test results indicated that the amounts of corrosion increased by -rays irradiation both air and nitrogen atmosphere. And also corrosion amounts increased with -ray dose rates. Electrochemical analyses indicated that cathodic reaction of Hydrogen peroxide was controlled by diffusion process. The measured diffusion constant of H
O was about 0.75 times to that of oxygen. From these results, it is estimated that corrosion of LAS and CS in -ray irradiated condition was evaluated by the cathodic reduction reaction of oxidant.