The thermal conductivities of UO₂ containing Xe bubbles were investigated using non-equilibrium molecular dynamics (MD) simulations as a function of porosity, bubble radius and the ratio of Xe atoms to U vacancies (Xe:V_U). It was found that when the pores are filled with Xe atoms to form bubbles, the porosity and radius of the bubble both increase with the increase in Xe:V_U. Based on the equilibrium porosity and bubble radius, a previous model for porous UO₂ was used to predict the thermal conductivity. This model predicted only a slight change in the thermal conductivity with Xe:V_U, which is induced by the changes in porosity and bubble radius. However, according to MD simulations, the thermal conductivity of UO₂ containing Xe bubbles decreases obviously with Xe:V_U. This indicates that in addition to porosity and bubble size effects, there exists another mechanism for the degeneration in UO₂ thermal conductivity due to the presence of Xe bubbles. MD details revealed that many defects are produced on UO₂/bubble interface, the concentration of which increases with Xe:V_U. This leads to the increase in interfacial thermal resistance (ITR), thus resulting in the decrease in overall thermal conductivity. Based on the previous model for porous UO₂, a model considering the above mechanism was established for UO₂ containing Xe bubbles through phenomenological phonon hydrodynamics. In this model, the increase in ITR is reflected by multiplying the thermal-drag force by a correction factor. The proposed model can be implemented in fuel performance codes to improve calculations of fuel thermal conductivity.

使用非平衡分子动力学（MD）模拟研究了含UO ₂的Xe气泡的热导率，它是孔隙率，气泡半径和Xe原子与U空位之比（Xe：V _U）的函数。发现当孔隙中充满Xe原子形成气泡时，气泡的孔隙率和半径都随Xe：V _U的增加而增加。基于平衡孔隙率和气泡半径，使用多孔UO ₂的先前模型来预测热导率。该模型预测，随着Xe：V _U的导热率仅发生微小变化，这是由孔隙率和气泡半径的变化引起的。然而，根据MD模拟，含Xe气泡的UO ₂的热导率随Xe：V _U明显降低。这表明，除了孔隙率和气泡尺寸效应外，由于存在Xe气泡，还存在另一种导致UO ₂导热性降低的机理。MD细节显示，在UO ₂ /气泡界面上产生许多缺陷，其浓度随着Xe：V _U的增加而增加。这导致界面热阻（ITR）的增加，从而导致整体热导率的降低。基于多孔UO ₂的先前模型，通过现象学声子流体动力学，建立了考虑上述机理的含Xe气泡的UO ₂的模型。在此模型中，ITR的增加是通过将热阻力乘以校正因子来反映的。可以在燃料性能代码中实施提出的模型，以改善燃料导热系数的计算。