Modelling radiation-induced oxidative dissolution of UO2-based spent nuclear fuel on the basis of the hydroxyl radical mediated surface mechanism: Exploring the impact of surface reaction mechanism and spatial and temporal resolution

Abstract

A combined kinetic and diffusion model with an accurate α-dose rate profile was used to model radiation induced dissolution of UO2. Previous experimental data were used to fit the surface site reaction system involving the surface bound hydroxyl radical as an intermediate species for both UO2 oxidation and surface catalysed decomposition of H2O2. The performance of the model was explored in terms of sensitivity to spatial and temporal resolution as well as simplifications in the models describing the surface reactions and the reactions in solution. As a result, optimal conditions for running the numerical simulations were identified.