|About this Abstract
||MS&T23: Materials Science & Technology
||Ceramics for New Generation Nuclear Energy System Application
||Impact of Phonon Resonant Scattering on Thermal Conductivity of Uranium-doped ThO2
||Saqeeb Adnan, Zilong Hua, Erika Nosal, Amey Khanlokar, David Hurley, Marat Khafizov
|On-Site Speaker (Planned)
Thermal transport properties of thoria (ThO2) are of critical interest in nuclear energy applications and can be altered by the generation of defects and atomic substitutions under extreme reactor conditions. In this study, we investigate the low-temperature thermal transport behavior of single crystal ThO2 with varying degrees of U doping from 0 to 100%. Thermal conductivity was measured using modulated thermo-reflectance technique and analyzed using analytical model for phonon mediated thermal transport. Our results demonstrate the significance of including a resonant phonon scattering term in capturing the low temperature thermal conductivity behavior. This added resonant term accounts for the phonon scattering from the localized vibrational modes created by the dopant uranium's 5f electrons interacting with the lattice. The optimized model parameters demonstrated a steep resonant effect after the U doping has reached 60%. We also highlight the inadequacy of Rayleigh scattering in explaining low-temperature thermal transport properties in impurity-induced thoria.