An improved model for the corrosion of used nuclear fuel inside a failed waste container under permanent disposal conditions

摘要

An improved model for nuclear fuel corrosion inside a failed waste container has been developed. The model considers the influence of the α-radiolysis products using a full radiolytic reaction set, and demonstrates that H_2O_2 is the dominant oxidant. Corrosion of the fuel is modelled considering both the direct oxidation of UO_2 by H_2O_2 and the galvanically-coupled oxidation by H_2O_2 reduction on noble metal (ε) particles. Corrosion has been found to be very sensitive to the corrosion products of steel container, Fe~(2+) and H_2. The surface coverage of ε-particles can significantly influence the dissolution rate.