论文标题
高声子散射速率抑制二氧化铀铀中的热导率
High Phonon Scattering Rates Suppress Thermal Conductivity in Hyperstoichiometric Uranium Dioxide
论文作者
论文摘要
二氧化铀（UO $ _2 $）是最重要的核燃料之一，可以积聚多余的氧原子作为间隙缺陷，从而显着影响热特性。在这项研究中，在低温（2-300 k）上进行了热导率和UO $ _2 $和UO $ _ {2+x} $的非弹性中子散射测量测量值（x = 0.3、0.4、0.8、0.11）。与UO $ _2 $相比，UO $ _ {2+X} $的导热率显着抑制，除非在Néel温度tn = 30.8 K附近，在那里它独立于x。声子测量结果表明，UO $ _2 $和UO $ _ {2+X} $的热能和声子组速度相似，并且高音调散射速率的UO $ _ {2+X} $中抑制的热导率。这些新见解提高了我们对晚期核燃料中热运输特性的基本理解。
Uranium dioxide (UO$_2$), one of the most important nuclear fuels, can accumulate excess oxygen atoms as interstitial defects, which significantly impacts thermal properties. In this study, thermal conductivities and inelastic neutron scattering measurements on UO$_2$ and UO$_{2+x}$ (x=0.3, 0.4, 0.8, 0.11) were performed at low temperatures (2-300 K). The thermal conductivity of UO$_{2+x}$ is significantly suppressed compared to UO$_2$ except near the Néel temperature TN= 30.8 K, where it is independent of x. Phonon measurements demonstrate that the heat capacities and phonon group velocities of UO$_2$ and UO$_{2+x}$ are similar and that the suppressed thermal conductivity in UO$_{2+x}$ results from high phonon scattering rates. These new insights advance our fundamental understanding of thermal transport properties in advanced nuclear fuels.
