TY - JOUR
ID - 1595
TI - Investigation of phonon properties and thermal behavior of UO2 crystal using density-functional theory
JO - Iranian Journal of Physics Research
JA - IJPR
LA - en
SN - 1682-6957
AU - Payami Shabestar, M
AU - Sheykhi, S
AD - Physics and Accelerators Research School, Nuclear Science and Technology Research Institute, AEOI, Tehran, Iran
Y1 - 2020
PY - 2020
VL - 20
IS - 1
SP - 65
EP - 72
KW - uranium dioxide
KW - phonon
KW - phonon scattering rate
KW - phonon mean free path
KW - Boltzmann transport equation
DO - 10.47176/ijpr.20.1.38881
N2 - Understanding thermal behavior and processes underlying the heat transport of UO2 nuclear fuel in nuclear reactor plays a key role in predicting the efficiency of the fuel. If the heat transport, which is an important parameter in temperature distribution of the fuel, does not occur properly, the continuous increase of temperature would lead to the melting of the fuel and therefore, environmental hazards. In this work, by using a non-spin-polarized calculation for the simple description of the paramagnetic state and ignoring the Hubbard correction, the thermal properties and phonon properties of bulk UO2 are calculated. These calculations are based on the density-functional theory (DFT) and density-functional perturbation theory (DFPT). To determine the lattice-vibration properties by the finite-displacement method, we have calculated the second-order and third-order force constants based on which such quantities as constant-volume specific heat, Gruneisen parameter, three-phonon scattering rate, scattering rate due to different levels of isotopic enrichment, and cumulative thermal conductivity are calculated. The results of the calculated specific heat based on the harmonic approximation show a good agreement with the experimental values, specifically for temperatures lower than 400 Kelvin. The results obtained for three-phonon scattering rate reveal that the scattering rate increases with temperature, thereby leading to the decrease of thermal conductivity. The results related to different levels of isotopic enrichments do not show any sensible changes in the scattering rates.
UR - https://ijpr.iut.ac.ir/article_1595.html
L1 - https://ijpr.iut.ac.ir/article_1595_d8d530e129d06582be7110f870d203a4.pdf
ER -