Fabrication of stoichiometric U(3)Si(2) fuel pellets

Uranium silicide, U(3)Si(2), is an accident tolerant fuel type which is gaining momentum as a replacement fuel for uranium dioxide (UO(2)). Idaho National Laboratories has been fabricating phase pure U(3)Si(2) fuel pellets for use in various irradiation and material characterization experiments. Stoichiometric U(3)Si(2) fuel pellets were fabricated using a powder metallurgy and arc melting technique. The use of the stoichiometric ratio to alloy uranium and silicon, and sintering in a vacuum environment allowed for the fabrication of high density (>94% theoretical density), phase pure pellets, greater than 94% U(3)Si(2). Silicon volatilization was not observed in the as-sintered microstructure, which has been verified through XRD and SEM, thus eliminating the need to alloy a substoichiometric U/Si ratio. • Stoichiometric ratio of U to Si used to form U(3)Si(2) phase. • Decrease in secondary phases present confirm absence of silicon volatilization. • Analysis via XRD and SEM confirm the phase purity of the U(3)Si(2) fuel pellets.