Effect of radiation on carbon steel corrosion in compacted bentonite

Taniguchi, Naoki ; Yamaguchi, Makoto; Naito, Morimasa ; Tateishi, Tsuyoshi*

Corrosion tests of carbon steel were performed to estimaste possible effect of groundwater radiolysis by radiation from vitrified waste on corrosion rate of carbon steel overpack in HLW repository. While average corrosion rates from weight loss increased by radiation (dose rate : 30-50 Gy/h) in synthetic seawater, accompanying increased corrosion potential and cathodic current density possibly due to contribution of radiolytically generated oxidants such as hydrogen peroxide participated in cathodic reaction. On the other hand, no apparent effect of radiation was observed for samples in compacted bentonite buffer. In addition, corrosion rates little affected by dry density of bentonite buffer. A plausible mechanism was considered to explain the absence of the radiation.