Some considerations on the thermal conductivity of stoichiometric uranium dioxide at high temperatures

Lattice thermal conductivity of UO2 using ab-initio and classical molecular dynamics

“…Also, it has been suggested that charge carriers play a role only at the high temperatures, while phonons are the dominant carriers at low and moderate temperatures. 1,4,5,10,20,22,24 This phonon behavior (and lattice dynamics) of UO 2 is clearly explained by the recent atomic-level simulations based on the density-functional theory (DFT), including the prediction of significant anharmonicity 25 and mechanical/thermodynamic/ vibrational properties. 26,27 In the high-temperature regime, many report that the thermal conductivity of UO 2 is dominated by the charge-carrier transport.…”

“…To explain the heat conduction mechanisms in UO 2 , various theoretical, [3][4][5] computational, [6][7][8][9] and experimental 9-23 studies have been performed over the last five decades. These include the effects of the crystalline structure, 9,10,[20][21][22][23] non-stoichiometry, 5,16 porosity, 12,18 and irradiation.…”

“…26,27 In the high-temperature regime, many report that the thermal conductivity of UO 2 is dominated by the charge-carrier transport. 1,4,5,10,20,22,24 Despite the semiconductor features of the UO 2 crystal (bandgap energy DE e;g $ 2.0 eV), 3,28-30 the classical band theory is inadequate in describing its electrical properties. 1, 3,4,28,[31][32][33][34][35] To explain the high-temperature behavior of its thermal conductivity, the small-polaron hopping mechanism has been suggested.…”