Thermal Resistance of CeO2 Grain Boundaries
Damage to nuclear fuel microstructure from neutron radiation can result in sharp local changes of it's thermal properties. A better understanding of these properties, including the thermal resistance across grain boundaries, can help predict nuclear fuel performance and improve nuclear reactor efficiency and safety. While Uranium is the main element used as nuclear fuel, CeO2 has many similar properties to it and is therefore a comparable and easier alternative to measure. The measuring and recording of the thermal resistance across grain boundaries hasn't been explored very much. The spatial scan photothermal reflectance technique was used in this study as it provides a non-contact, micron-sized spatial resolution capability. The sample is heated by a modulated heating laser beam near one of the grain boundaries. When the induced thermal wave propagates across the interface, the phase shift created by the resistance is recorded. A multi-parameter fitting process is then used to extract the thermal resistance from the phase profile. The measurements were repeated across a wide number of grain boundaries, and the relative statistical analysis was performed. Different thermal resistances were measured at different grain boundaries. The results suggest a significant dependence on grain boundary thickness and grain geometry. Other contributing factors can also be grain orientation, impurities, or temperature dependent thermal transport diffusivity.
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Jesse Spackman (POC,Primary Presenter), Utah State University, firstname.lastname@example.org;
Zilong Hua (Co-Author), Utah State University, email@example.com;