The presence of stable facets of nanobubbles in crystal lattice can significantly affect their diffusion coefficient, but the existing theory of this phenomenon is too general and can not take into account atomistic structure of nanobubbles in a given material. Such a theory for the mechanisms of bubble motion in crystals can be extended and developed using methods of atomistic modelling. In this work, we consider the movement of bubbles in the bcc lattice of γ-U. The Beere's theory of faceted bubble motion is revised and a method of non-equilibrium accelerated molecular dynamics in a pressure gradient is proposed. The results of the accelerated method calculations for γ-U are verified using generic molecular-dynamics calculations of free nanobubble diffusion. The new method significantly accelerates calculations of the diffusion coefficient for nanometer-sized bubbles and opens the way for more accurate material-specific calculations of gas-filled nanobubbles diffusivity in nuclear fuels.

晶格中纳米气泡稳定面的存在会显着影响其扩散系数，但是这种现象的现有理论过于笼统，无法考虑给定材料中纳米气泡的原子结构。可以使用原子建模方法来扩展和发展这种晶体中气泡运动机理的理论。在这项工作中，我们考虑了γ-U的bcc晶格中气泡的运动。修正了比尔的多面气泡运动理论，并提出了一种在压力梯度下非平衡加速分子动力学的方法。使用自由纳米气泡扩散的通用分子动力学计算验证了γ-U加速方法计算的结果。