A ternary EAM interatomic potential for U–Mo alloys with xenon

Abstract

A new interatomic potential for a uranium-molybdenum system with xenon is developed in the framework of an embedded atom model using a forcematching technique and a dataset of ab initio atomic forces. The verification of the potential proves that it is suitable for the investigation of various compounds existing in the system as well as for simulation of pure elements: U, Mo and Xe. Computed lattice constants, thermal expansion coefficients, elastic properties and melting temperatures of U, Mo and Xe are consistent with the experimentally measured values. The energies of the point defect formation in pure U and Mo are proved to be comparable to the density-functional theory calculations. We compare this new U-Mo-Xe potential with the previously developed U and Mo-Xe potentials. A comparative study between the different potential functions is provided. The key purpose of the new model is to study the atomistic processes of defect evolution taking place in the U-Mo nuclear fuel. Here we use the potential to simulate bcc alloys containing 10 wt% of intermetallic Mo and U 2 Mo.

Atomistic modeling of the self-diffusion in γ-U and γ-U-Mo

“…In this study, we simulated γ U and U-Mo alloys with the classical MD method using our previously developed many body potentials [23][24][25], as well as the potential proposed by Beeler et al [26] to describe the properties of defects in γ U. We present the results found when considering diffusion in γ U and U-Mo with these potentials.…”

“…To investigate the properties of uranium and ura nium-molybdenum alloys, several EAM potentials were developed, including the one for the description of liquid uranium and γ phase at high temperatures T and pressures P up to 350 GPa [33]; the one for uranium in three various phases, i.e., α U, γ U, and the melt [23,24]; and the one for the ternary system: uranium and molybdenum with xenon [25].…”

“…When working over potentials [23][24][25], which are oriented to the investi gation of the properties of α U, γ U, and U-Mo alloys, another method of potential fitting was select ed⎯it is called force matching [34]. The idea of the method consists of producing the interatomic poten tial based on ab initio data (interatomic forces, ener gies, and stresses) calculated for certain reference structures.…”

Atomistic simulations of the small xenon bubble behavior in U–Mo alloy

“…In this work, we utilized the embedded atom method (EAM) potential proposed by Smirnova et al [19] using a force matching technique and a dataset of ab initio atomic forces. The EAM interatomic potential has been proved to be able to correctly reproduce the lattice constant, modulus of elasticity, room temperature density and melting temperature of U-10 wt% Mo alloy crystal and the pressure-volume dependence of Xe across a broad range.…”

“…Especially, the room-temperature isotherm of α-U, molybdenum and FCC xenon under very high pressures is reproduced with good accuracy, which confirms the EAM potential is very suitable for solving the problems dealing with the small xenon bubble behavior in U-Mo alloy under high pressures. The details of the potential parameters have been discussed elsewhere [19].…”