Experimental verification of models assessing Eh evolution induced by corrosion of carbon steel overpack

Sakamaki, Keiko ; Kataoka, Masaharu; Maeda, Toshikatsu; Iida, Yoshihisa ; Kamoshida, Michio; Yamaguchi, Tetsuji ; Tanaka, Tadao 

Corrosion experiments of a carbon steel plate embedded in bentonite mixture were conducted toverify our models assessing Eh evolution induced by corrosion of carbon steel overpack. Theexperimental results showed that the Eh decreased for the first 200 days and was subsequentlystabilised at around -450 mV; corrosion products were identified as magnetite and Fe waspresent mostly as divalent Fe within a 5 mm range from the carbon steel plate. Reactive transportmodelling was performed to assess the Eh evolution in the system using kinetic dissolution modelfor metallic iron and thermodynamic equilibrium models for other chemical reactions and closelyreproduced the experimental results. The models were verified only under the conditionsemployed in this study.