Irradiation Effect on Noble Metal Particles in Water Using in situ Liquid Cell STEM Observation

During geologic disposal of spent nuclear fuel (SNF) in an engineered nuclear waste repository, once all other barriers have degraded, oxidizing may occur at the solid-water interface owing to a self-generated radiolytic field.The repository design includes large quantities of iron (Fe), that is anticipated to corrode under an anoxic environment, and generate hydrogen (H2) gas [1,2].This H2 gas is thought to be able to suppress the dissolution of SNF through a catalytic reaction with noble metal particles (NMP) that are pre-existing in the SNF.This interaction leads to the decomposition of the major oxidant, hydrogen peroxide (H2O2) [3].These processes are described in the Fuel Matrix Degradation (FMD) model that is being used to predict SNF degradation rates.The NMP, therefore, plays a important role