The so‑called supercontainer (SC) concept is currently being considered as reference design for the final disposal of vitrified high-level radioactive waste and spent fuel in Belgium. It comprises a prefabricated Portland cement based buffer that completely surrounds a carbon steel overpack. In this highly alkaline environment (pH ~ 13.6), and under normal conditions (i.e. without the ingress of aggressive species), the carbon steel overpack will be protected by a passive oxide film, which is expected to result in very low uniform corrosion rates. Considering the long timescales applicable to waste disposal, determining accurate and reliable estimates of the uniform corrosion rate under anoxic conditions forms a very important part of the safety and feasibility strategy. On the other hand, the occurrence of localised forms of corrosion cannot be neglected and therefore it is also crucial to demonstrate that no other form of corrosion apart from uniform corrosion can take place.
This paper presents the progress of the research that has been made since the LTC2016 Workshop (Toronto, Canada) on the uniform corrosion, pitting corrosion and stress corrosion cracking (SCC) behaviour of P355 QL2 grade carbon steel exposed to an artificial concrete porewater solution.
carbon steel, concrete, alkaline, uniform corrosion, pitting corrosion, stress corrosion cracking, anaerobic, sulphide, thiosulphate, chloride