Benjamin Beeler1 Larry Aagesen1 Michael Baskes3 4 Andersson David2 Michael Cooper2 Yongfeng Zhang1

1, Idaho National Laboratory, Idaho Falls, Idaho, United States
3, University of California, San Diego, San Diego, California, United States
4, Mississippi State University, Starkville, Mississippi, United States
2, Los Alamos National Laboratory, Los Alamos, New Mexico, United States

Uranium-silicide (U-Si) fuels are being pursued as a possible accident tolerant fuel (ATF). This uranium alloy fuel benefits from higher thermal conductivity and higher fissile density compared to UO2. In order to perform engineering scale nuclear fuel performance simulations, the material properties of the fuel must be known. Currently, the experimental data available for U-Si fuels is rather limited. Thus, multiscale modeling efforts are underway to address this gap in knowledge. Mesoscale modeling methodologies, such as phase-field, require information on the fundamental properties of the material system of interest. This information includes, but is not limited to, point defect energies, diffusivities and interfacial energies. In this study, an interatomic potential for U-Si is implemented for the investigation of interfaces in U3Si2. A variety of planar free surfaces, voids, and twist and tilt grain boundaries are investigated. This information is implemented in a phase-field model to predict the swelling behavior of U3Si2.