International Collaboration to Advance the Technical Readiness of High Uranium Density Fuels and Composites for Small Modular Reactors

This project seeks to understand the importance of a range of factors on how specific High Density (nuclear) Fuels (HDFs) behave under accident conditions. At present both UN and UB2 are promising future fuel materials to replace UO2, enabling more robust cladding solutions to be implemented by improving fuel cycle economics. Their deployment is challenging due to an observed rapid reaction with high temperature steam, an environment likely to be encountered during any postulated cladding failure in a light water reactor (such as a GW-scale commercial plant, or Small Modular Reactor).

At present this reaction is poorly understood, and limited by confounding results from international institutions. The proposed work seeks to address this by adopting a round-robin approach, with a range of international collaborators exchanging both samples and data, in a bit to develop a mechanistic understanding of UN hydrolysis behaviour.

Furthermore, composite UN-UB2 fuel will be manufactured which has been seen to drive improvements with UN onset temperature, but also remains understood. By developing a deeper mechanistic understanding of UN behaviour and the importance of typical light element contaminants, we will seek to explore the effect of UB2 on UN fuels, and hence develop more resistant future fuel forms.