A model for the influence of steel corrosion products on nuclear fuel corrosion under permanent disposal conditions

A model was developed to determine the influence of steel corrosion products on α-radiolytic corrosion of spent nuclear fuel inside a failed waste container. The model takes into account the α-radiolysis of water, the reaction of radiolytic H2O2 with UO2 both directly and via galvanic coupling with noble metal particles, the reaction with H2 via galvanic coupling, and the Fenton reaction. The dominant redox control agent was found to be H2, and the critical H2 concentrations required to completely suppress fuel corrosion were calculated. The ability of Fe2+ to scavenge H2O2 had only a minor influence on fuel corrosion processes.

► The corrosion of spent nuclear fuel inside a failed waste container is modeled.
► Alpha-radiolytic corrosion of UO2 is influenced by steel corrosion products.
► The dominant redox control agent is H2, while Fe2+ has a minor influence.
► H2 concentrations required to completely suppress fuel corrosion is calculated.
► Influences of diffusion length, dose rate, and redox reactions are examined.