This work presents an investigation of the mechanical properties of uranium-molybdenum(UMo) nuclear fuel through atomistic simulations, combining classical molecular dynamicsand ab initio calculations.Classical molecular dynamics (CMD) calculations, leveraging the angular dependent potential(ADP) developed by Starikov et al.[1], were first employed to compute the density and elasticconstants of two uranium phases, molybdenum, and UMo alloy across different temperatures.This initial set of results was then compared to existing experimental data, showing overallagreement although some discrepancies were observed. Complementary ab initio simulationswere also performed at 0 K, and provided additional data on bulk moduli and atomic volumes,also displaying reasonable agreement with existing experimental data. Those calculationsserved as a reference point for the next steps of our investigation.We then proposed the development of Spectral Neighbor Analysis Potentials (SNAP), for purematerials and for the alloy. Those interatomic potentials were developed using an activelearning tool (MLACS) that combines both ab initio and CMD simulations. These SNAPpotentials reproduced the density, uranium density and elastic constants of U-10Mo (a targetedcomposition for usage as nuclear fuel in research reactors), with high accuracy, validating theiruse for atomistic simulations of this alloy. However, performance for other compositions wasless consistent, likely due to limited training data.Overall, the developed SNAP potentials provide with a reliable foundation for moleculardynamics studies of U-10Mo, while additional ab initio data and broader compositionalcoverage is required for more general usage for the potentials.

This work presents an investigation of the mechanical properties of uranium-molybdenum(UMo) nuclear fuel through atomistic simulations, combining classical molecular dynamicsand ab initio calculations.Classical molecular dynamics (CMD) calculations, leveraging the angular dependent potential(ADP) developed by Starikov et al.[1], were first employed to compute the density and elasticconstants of two uranium phases, molybdenum, and UMo alloy across different temperatures.This initial set of results was then compared to existing experimental data, showing overallagreement although some discrepancies were observed. Complementary ab initio simulationswere also performed at 0 K, and provided additional data on bulk moduli and atomic volumes,also displaying reasonable agreement with existing experimental data. Those calculationsserved as a reference point for the next steps of our investigation.We then proposed the development of Spectral Neighbor Analysis Potentials (SNAP), for purematerials and for the alloy. Those interatomic potentials were developed using an activelearning tool (MLACS) that combines both ab initio and CMD simulations. These SNAPpotentials reproduced the density, uranium density and elastic constants of U-10Mo (a targetedcomposition for usage as nuclear fuel in research reactors), with high accuracy, validating theiruse for atomistic simulations of this alloy. However, performance for other compositions wasless consistent, likely due to limited training data.Overall, the developed SNAP potentials provide with a reliable foundation for moleculardynamics studies of U-10Mo, while additional ab initio data and broader compositionalcoverage is required for more general usage for the potentials.