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Description
Thermal conductivity is one of the most important property of nuclear fuel materials affecting many processes such as swelling, grain growth, and fission gas release and limits the transfer of the linear power [1].
However, the measurement of thermal conductivity is difficult even for simple elements like silicon. Loss of heat through convection, conduction, and radiation coexist at the same time. Measuring radioactive elements is even more difficult because of the sample self-heating. This makes the theoretical calculations appreciated and a valuable tool.
Here we demonstrate to determine not only the total conductivity but their electronic and phononic (lattice vibrations) contributions as a function of temperature just based on quantum-mechanical calculations. The forces on atoms to the third order are accurately calculated and derived results are presented for the thorium metal and thorium monocarbide. In addition, the analysis which vibration modes transfer most of the heat here was performed.
[1] T. R. G. Kutty, J. Banerjee, and A. Kumar, in Thoria-based Nuclear Fuels (Springer London, 2013) pp. 11–70.
