Xenon Diffusion Mechanism and Xenon Bubble Nucleation and Growth Behaviors in Molybdenum via Molecular Dynamics Simulations

Abstract

The behaviors of xenon in molybdenum were studied using molecular statics andmolecular dynamics simulations. The diffusion mechanism of xenon atoms was studied combiningmolecular dynamics, nudged elastic band, and temperature-accelerated dynamics methods. Thevacancy-assisted diffusion mechanism was analyzed and the corresponding energy barriers werecalculated. The clustering process of scattered xenon atoms was studied at an elevated temperature.Xenon bubbles were observed to form when the concentration of xenon atoms exceeded a thresholdconcentration value. Meanwhile, the interaction of xenon bubble and vacancies was investigated viathe nudged elastic band method. The results showed that there exists a region around the xenonbubble where the migration energy of vacancy is significantly influenced. This work provides usefulinsights towards a better understanding of the behaviors of xenon in molybdenum.

Effects of Point Defects on the Stable Occupation, Diffusion and Nucleation of Xe and Kr in UO2

“…A similar phenomenon occurred while studying Mo. Zhang et al [16] studied the clustering process of Xe atoms dispersed in Mo at high temperatures. They observed the formation of Xe bubbles when the concentration of Xe atoms exceeded the threshold concentration value.…”

“…Consequently, several separation effect experiments have been proposed to simplify complex material systems by describing the physical processes of one or more fission gases to elucidate the underlying behavioural mechanisms. Thus, Zhang et al [16] briefly explained the mechanism of UO 2 by simulating molybdenum.…”

ATOMIC SIMULATIONS OF VOIDS IN U-10wt%Mo FUEL

“…Shenyang Hu et al [2] pointed out three possible mechanisms as responsible for nanobubble superlattice formation: elastic interaction, one-dimensional migration of selfinterstitial atoms, and dislocation punch out. Several theoretical works can be found in the literature [2,[5][6][7][8] exploring such mechanisms mostly under the assumption that they * pascuet@cnea.gov.ar may be due to overpressurized bubbles. Nevertheless, Salvato et al [9] recently found that, at low burnup, i) nanobubble lattice forms preferentially at grain boundaries and extends to the grain interior with increasing irradiation dose, and ii) bubbles are extremely underpressurized, suggesting its void-like nature.…”