Atomic Simulations of U-Mo under Irradiation: A New Angular Dependent Potential

Uranium-Molybdenum alloy has been a promising option in the production of metallic nuclear fuels, where the introduction of Molybdenum enhances mechanical properties, corrosion resistance, and dimensional stability of fuel components. Meanwhile, few potential options for molecular dynamics simulations of U and its alloys have been reported due to the difficulty in the description of the directional effects within atomic interactions, mainly induced by itinerant f-electron behaviors. In the present study, a new angular dependent potential formalism proposed by the author's group has been further applied to the description of the U-Mo systems, which has achieved a moderately well reproduction of macroscopic properties such as lattice constants and elastic constants of reference phases. Moreover, the potential has been further improved to more accurately describe the threshold displacement energy surface at intermediate and short atomic distances. Simulations of primary radiation damage in solid solutions of the U-Mo system have also been carried out and an uplift in the residual defect population has been observed when the Mo content decreases to around 5 wt.%, which corroborates the negative role of local Mo depletion in mitigation of irradiation damage and consequent swelling behavior.

Automated summary

Uranium-Molybdenum alloy is a promising option in the production of metallic nuclear fuels, with the introduction of Molybdenum enhancing mechanical properties. However, there are few potential options for molecular dynamics simulations of U and its alloys due to difficulties in describing directional effects within atomic interactions. A new angular dependent potential formalism has been proposed and applied to describe the U-Mo systems, achieving moderately accurate reproduction of macroscopic properties and improving the accuracy of describing threshold displacement energy surface. Simulation of primary radiation damage in solid solutions of the U-Mo system showed an increase in residual defect population as Mo content decreases, indicating the negative role of Mo depletion in mitigating irradiation damage.