EURAD - D15.1 ConCorD Initial SotA

This report provides a review of the current state of the knowledge on the corrosion behaviour of candidate container materials for the disposal of spent fuels (SF) and high-level radioactive waste (HLW). The influence of radiation, microbiological activity and of time dependent transformations of the physical, chemical and thermochemical properties of the bentonite barriers in contact with the metallic containers, e.g., temperature, saturation with geological waters, compaction, and chemical changes, are emphasized. The degradation mechanisms and the estimations of container durability derived from them are recognized as mature in the case of so-called traditional materials such as carbon steel and copper. On the other hand, a series of novel ceramic and metallic materials of potentially improved performance are being developed, but whose corrosion properties and mechanisms are still unexplored.
Therefore, reliable comprehensive corrosion mechanisms covering the different materials in predictable changing environmental conditions have still to be developed to improve the long-term safety prognoses. This review aims to constitute a basis guide, upon which research activities should be designed to yield a fruitful advance in covering the gaps still open in the elucidation of complex corrosion mechanisms, namely the corrosion behaviour of classical materials under perturbations of the environment and those still unknown of the new developed materials. The context is mainly referred to national programs being carried out in Europe, with some references to programs from non-European countries for the sake of completeness.