Ball Milling and Spark Plasma Sintering of Cerium Silicides as a Surrogate Nuclear Fuel
Uranium silicide (U3Si2) is under consideration as a more uranium-dense replacement for UO2 in Light Water Reactors. Fuel pellets are typically produced by arc melting, crushing, and pressureless sintering, but this process is slow and resulting fuel is porous and inhomogeneous. Ball milling and Spark Plasma Sintering (SPS) are two novel processing techniques that are being investigated to achieve high density, compositionally homogenous fuel with minimal processing time. In this study, cerium silicides were used as a surrogate material to investigate the feasibility of high-energy ball milling and Spark Plasma Sintering (SPS) for the production of uranium silicide. Ball milling was studied as a function of time and composition. Each milled composition was then sintered by pressureless and SPS techniques. Samples were characterized after milling and after sintering by Scanning Electron Microscopy (SEM), Energy Dispersive Spectroscopy (EDS) and X-ray Diffraction (XRD) to determine morphology, composition, and phase purity. The characterization results show that high-energy ball milling produces homogeneous alloys in less than one hour, while SPS processing greatly reduces porosity and saves considerable time in sintering. This work verifies that these novel processing techniques produce superior results when compared to more traditional fabrication methods.