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MM: Fachverband Metall- und Materialphysik
MM 16: Transport - Heat Transport and Thermoelectricity
MM 16.2: Vortrag
Montag, 16. März 2020, 17:15–17:30, IFW A
Thermal conductivity of Th and ThC — •Lukas Kyvala and Dominik Legut — VSB - Technical University of Ostrava, 17. listopadu 15, 70833 Ostrava-Poruba, Czech Republic
Thermal conductivity is one of the most important properties of nuclear fuel materials affecting many processes such as swelling, grain growth, and fission gas release and limits the transfer of the linear power.
Experimental measurement of thermal conductivity is difficult because of the loss of heat through convection, conduction, and radiation. The different measurements do not find full agreement even for such a simple case like silicon. Moreover, the measurement of radioactive elements is complicated due to the self-heating. Theoretical calculations are then a very useful tool.
We demonstrate the success of predicting the thermal conductivity of potential nuclear fuels like Th and ThC using electron-structure calculations. Both phonon (lattice) and electron contributions were calculated as a function of temperature.
Next, we discuss why the total thermal conductivity of thorium metal is more than twice as large as thorium monocarbide and why the optical phonon modes of ThC accounting only for approximately 6 % of the total phonon contribution. This result differs significantly from NpO2 where the optical branches contribute only 27 %.