Regarding the long-term storage of spent Cs adsorption vessels containing zeolites in the Fukushima Daiichi nuclear power station, corrosion of the material of the spent Cs adsorption vessels is one of the important issues. We performed electrochemical tests of stainless steel (SUS316L) in the zeolites containing artificial seawater under gamma-ray irradiation. The spontaneous potential (
ESP) and critical pitting potential (
VC) of SUS316L were measured to understand the corrosion resistance of the stainless steel in this study. The rest potential of the stainless steel increased with time after gamma-ray irradiation.
ESP, defined as the steady rest potential, increased with increasing dose rate; this increase in
ESP was suppressed by the contact of SUS316L with the zeolites. The concentration of H
2O
2 in bulk water increased with increasing dose rate. This concentration increase was suppressed by the contact of SUS316L with the zeolites due to decomposition of H
2O
2. There was good relationship between
ESP and the concentration of H
2O
2. The
VC of SUS316L contacted with the zeolites decreased with increasing Cl
- ion concentration and is slightly smaller than the
VC in bulk water. The contact of SUS316L with the zeolites suppressed the increase in
ESP under irradiation. The contact with the zeolites can reduce the probability of the localized corrosion of SUS316L.
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