Study of corrosion rate of carbon steel in diluted artificial seawater under simulated irradiation condition

Komatsu, Atsushi ; Nakano, Junichi*; Tsukada, Takashi ; Ueno, Fumiyoshi  ; Yamamoto, Masahiro 

Seawater was injected into the reactor core in Fukushima 1st nuclear power plant for emergency cooling. Therefore it is concerned that primary containing vessel will corrode faster under irradiation in salt containing condition than usual. Corrosion rate of carbon steel in neutral water containing chloride ion is controlled by diffusion of dissolved oxygen. However hydrogen peroxide generated under ray irradiation will accelerate corrosion. In this study, diffusion coefficient and the thickness of diffusion layer for oxygen and hydrogen peroxide were measured to simulate corrosion rate of carbon steel. The ratio of diffusion limiting current density for hydrogen peroxide by oxygen was about 0.39 in the same concentration. Corrosion test was conducted and the result was compared to the simulation.