论文标题
UO2/BEO界面热电阻及其对燃料导热率的影响
UO2/BeO interfacial thermal resistance and its effect on fuel thermal conductivity
论文作者
论文摘要
UO2/BEO界面的界面热电阻（ITR）通过弥散不匹配模型（DMM）计算，研究了ITR对UO2-BEO热导率的影响。 DMM预测的ITR为10-9 m2k/w。使用此ITR，通过理论模型计算了UO2-BEO热导率，并与实验数据进行了比较。结果表明，DMM预测适用于UO2和分散的BEO之间的接口，而不适用于UO2和连续BEO之间的接口。如果含有连续BEO的UO2的热导率与实验数据一致，则其ITR应为10-6-6-10-5 m2k/w。因此，DMM考虑的UO2和BEO之间的振动不匹配是通过UO2/Exporesed-Beo界面减轻热通量的主要机制，但对于UO2/Continule-Beo界面而不是。此外，发现ITR的存在导致含有beo大小的UO2的导热率的依赖性。随着BEO尺寸的减小，UO2-BEO导热率降低。当BEO大小小于临界值时，UO2-BEO导热率甚至比UO2热导率更小。对于包含连续BEO的UO2，导热率随着BEO包围的UO2颗粒的尺寸的减小而降低，但不一定小于UO2导热率。在临界温度下，UO2-BEO热导率总是大于UO2热导率。在临界温度以上，只有当UO2颗粒尺寸足够大时，UO2-BEO热导率仅大于UO2热导率。得出了通过与BEO掺杂的靶向增强UO2热导率的条件。这些条件可用于设计和优化BEO的分布，内容，大小和UO2颗粒的大小。
UO2/BeO interfacial thermal resistance (ITR) is calculated by diffuse mismatch model (DMM) and the effects of ITR on UO2-BeO thermal conductivity are investigated. ITR predicted by DMM is on the order of 10-9 m2K/W. Using this ITR, UO2-BeO thermal conductivities are calculated by theoretical models and compared with experimental data. The results indicate that DMM prediction is applicable to the interface between UO2 and dispersed BeO, while not applicable to the interface between UO2 and continuous BeO. If the thermal conductivity of UO2 containing continuous BeO was to be in agreement with experimental data, its ITR should be on the order of 10-6 - 10-5 m2K/W. Therefore, the vibrational mismatch between UO2 and BeO considered by DMM is the major mechanism for attenuating the heat flux through UO2/dispersed-BeO interface, but not for UO2/continuous-BeO interface. Furthermore, it is found that the presence of ITR leads to the dependence of the thermal conductivity of UO2 containing dispersed BeO on BeO size. With the decrease in BeO size, UO2-BeO thermal conductivity decreases. When BeO size is smaller than a critical value, UO2-BeO thermal conductivity becomes even smaller than UO2 thermal conductivity. For UO2 containing continuous BeO, the thermal conductivity decreases with the decrease in the size of UO2 granule surrounded by BeO, but not necessarily smaller than UO2 thermal conductivity. Under a critical temperature, UO2-BeO thermal conductivity is always larger than UO2 thermal conductivity. Above the critical temperature, UO2-BeO thermal conductivity is larger than UO2 thermal conductivity only when UO2 granule size is large enough. The conditions for achieving the targeted enhancement of UO2 thermal conductivity by doping with BeO are derived. These conditions can be used to design and optimize the distribution, content, size of BeO, and the size of UO2 granule.
