We have investigated the grain boundary scattering effect on the thermal transport behavior of uranium dioxide (UO$_2$). The polycrystalline samples having different grain-sizes (0.125, 1.8, and 7.2 $μ$m) have been prepared by spark plasma sintering technique and characterized by x-ray powder diffraction (XRD), scanning electron microscope (SEM), and Raman spectroscopy. The thermal transport properties (the thermal conductivity and thermoelectric power) have been measured in the temperature range 2-300~K and the results were analyzed in terms of various physical parameters contributing to the thermal conductivity in these materials in relation to grain-size. We show that thermal conductivity decreases systematically with lowering grain-size in the temperatures below 30 K, where the boundary scattering dominates the thermal transport. At higher temperatures more scattering processes are involved in the heat transport in these materials, making the analysis difficult. We determined the grain boundary Kapitza resistance that would result in the observed increase in thermal conductivity with grain size, and compared the value with Kapitza resistances calculated for UO$_2$ using molecular dynamics from the literature.
Screened Coulomb interaction calculations: cRPA implementation and applications to dynamical screening and self-consistency in uranium dioxide and cerium
Comments on diffraction experiments at high-field on uranium dioxide in the ordered state
D. J. Antonio等人报告了在高磁场和低温下对二氧化铀进行的X射线衍射实验。作者显然没有意识到，衍射数据实际上明确地显示了在低温下由场引起的菱面体畸变的存在和多个畴的存在。我们的说明正确地分析了他们的数据。我们进行的晶体学分析是基于简单的参数，在轻微扭曲的立方材料的平面间距。在过去的50年里，许多材料都报道了类似的研究。我们的分析定量地解释了观测结果，两个峰的存在（作者认为这是意料之外的）以及它们相对于所施加的场的不同变化，这是原子体积守恒的简单结果。
Characterisation of slip and twin activity using digital image correlation and crystal plasticity finite element simulation: Application to orthorhombic $α$-uranium
Using Sohn's law of additive reaction times for modeling a multiparticle reactor. The case of the moving bed furnace converting uranium trioxide into tetrafluoride
A multiphase-field model for simulating the hydrogen-induced multi-spot corrosion on the surface of polycrystalline metals: Application to uranium metal
Combination of thermal and electric properties measurement techniques in a single setup suitable for radioactive materials in controlled environments and based on the 3-omega approach
为了有效地捕获核键的能量，先进的核反应堆概念寻求必须承受前所未有的极端温度和辐射的固体燃料。在这些先进燃料中，辐照下的热能传输直接关系到反应堆性能以及反应堆安全。由于计算和实验的复杂性，核燃料的热输运科学是一个巨大的挑战。在这里，我们提供了一个全面的审查的热输运研究两个锕系氧化物：一个目前在商业核反应堆中使用，二氧化铀（UO 2），和一个先进的燃料候选材料，二氧化钍（Th O 2）。在这两种材料中，热量都是由晶格波或声子携带的。裂变事件引起的晶体缺陷有效地散射声子，并导致燃料性能随着时间的推移而退化。在新的计算和实验工具的支持下，研究人员正在开发精确建模并最终控制先进核燃料热传输所需的基础工作。我们首先回顾了旨在理解完美单晶中的热输运的研究。缺陷的存在使得研究能够集中在声子输运的基本方面。接下来，我们回顾针对缺陷产生和演变的研究。在这里，重点是作为裂变产物造成的损害的替代品的离子辐照研究。最后，我们讨论的建模和实验的努力，直接在预测和验证中尺度的辐射缺陷的存在下的热输运。虽然在这些研究领域的努力是强大的，但在开发整体工具以捕获和预测各种环境条件下的热能传输方面仍然存在挑战性工作。
