Demonstrating Disposability of Advanced Gas-cooled Reactor (AGR) Spent Fuel in a Future Geological Disposal Facility - 21411

The UK is progressing plans to dispose of its Higher Activity Radioactive Waste via geological disposal. The inventory of wastes destined for disposal may include spent nuclear fuel including approximately 5,500,000 kg of spent Advanced Gas-cooled Reactor (AGR) fuel. This paper summarises the developing UK approach to demonstrating disposability of spent AGR fuel in a Geological Disposal Facility (GDF). A key parameter in models used to demonstrate that AGR fuel can be disposed safely is the radionuclide release rate. Initial desk-based studies concluded that it was reasonable to assume that radionuclide release rates of AGR fuel would be comparable to or bounded by that of Light Water Reactor spent fuel, which has been well studied internationally. Subsequently, AGR leaching experiments have been commissioned and the release rates measured further underpin this assumption. This AGR leaching project has also started to understand the differences and similarities between the two fuel types. This learning may also be applicable when considering the disposability of other UO₂ fuel types which are used, and proposed for use, in a range of nuclear reactor designs internationally. Significant progress has been made and, further research is planned to underpin a robust demonstration of AGR spent fuel disposability in a UK GDF. (authors)