The 5-reaction point defect oxide film model for iron in pH 13.5 at 80 °C

An iron canister is to be used as one of the barriers in the multi-barrier concept of the Belgian radioactive waste disposal system and is exposed to concrete. The underlying document describes the 5-reaction point defect oxide model for iron in a concrete pore solution with a pH of 13.5 at 80 °C with a view to implementing its corrosion rate calculation in performance assessment. Two issues need further attention. First, two approaches exist for parameterization of the 5-reaction model from impedance data. Both yield reasonable results when comparing measured and calculated impedance but differ in some model parameters. Secondly, and more importantly, the corrosion rate calculation from film growth and interstitial flux do not correspond with the present parameterization. These issues have to be resolved in respect of performance assessment.