Modeling the high-T paramagnetic state of bulk UO\(_2\) by a non-spin-polarized calculation and neglecting the Hubbard-U correction for the f electrons in U atoms, the lattice thermal conductivity of bulk UO\(_2\) is investigated by the exact solution of the Boltzmann transport equation for the steady-state phonon distribution function. The resulting phonon dispersion shows good agreement with experiment and when the non-analytical correction of the dynamical matrix was added, this agreement is enhanced. Analysis of the results shows that TA branches corresponding to U-atoms vibrations have the largest lifetimes and therefore have dominant role in thermal conductivity, while the optical branches corresponding mainly to O-atoms vibrations have the shortest lifetimes. Using this simple model, our results for the thermal conductivity show a very good agreement with the experiments. The calculations are repeated for bulk UO\(_2\) with different U-235 concentrations of 3%, 5%, 7% and 20%, and the results show a small decrease in thermal conductivity which arises from scattering of phonons by impurities.

通过非自旋极化计算对本体UO \（_ 2 \）的高T顺磁态建模，并且忽略了U原子中f电子的Hubbard-U校正，本体UO \（_ 2 \）的晶格热导率通过玻尔兹曼输运方程对稳态声子分布函数的精确解进行研究。所得的声子色散与实验显示出良好的一致性，并且当添加了动力学矩阵的非解析校正时，这种一致性得到了增强。结果分析表明，与U原子振动相对应的TA分支具有最大的寿命，因此在导热性中起主要作用，而主要与O原子振动相对应的光学分支的寿命最短。使用这个简单的模型，我们的导热系数结果与实验非常吻合。对批量UO \（_ 2 \）重复计算 U-235的不同浓度分别为3％，5％，7％和20％，结果表明，由于声子被杂质散射而引起的热导率小幅下降。