Exploring the effects of Al and Si dopants on the accident tolerant fuels of UO2 pellets for light water reactor

Abstract

This study investigates the potential of Al and Si dopants to enhance the performance of UO2 pellets used in accident tolerant fuel for light water reactors. These dopants are anticipated to improve the uranium loading level, fission product retention, and thermal conductivity of UO2 pellets, while preserving their neutronic performance. Utilizing first-principles calculations, this study analyzes the kinetics of UO2-Al and UO2-Si interactions, predicting the resulting compound types, compositions, properties, and doping techniques. The calculations consider the reaction products and their thermodynamic properties. The study proposes the use of uranium aluminide, uranium silicide, or uranium aluminum silicide (e.g., UAl3, USi, U3Si2, or U3Al2Si3) to fill the UO2 grain boundaries, as opposed to Al2O3 and SiO2. This could be achieved by synthesizing uranium aluminide and uranium silicide separately, and then mixing them with UO2.