Molecular dynamics simulation of thermodynamic properties in uranium dioxide

Xiangyu Wang, Bin Wu, Fei Gao, Xin Li, Xin Sun, Mohammed A. Khaleel, Ademola V. Akinlalu, Li Liu

Research output: Contribution to journalArticle

Abstract

In the present study, we investigated the thermodynamic properties of uranium dioxide (UO2) by molecular dynamics (MD) simulations. As for solid UO2, the lattice parameter, density, and enthalpy obtained by MD simulations were in good agreement with existing experimental data and previous theoretical predictions. The calculated thermal conductivities matched the experiment results at the midtemperature range but were underestimated at very low and very high temperatures. The calculation results of mean square displacement represented the stability of uranium at all temperatures and the high mobility of oxygen toward 3000 K. By fitting the diffusivity constant of oxygen with the Vogel-Fulcher-Tamman law, we noticed a secondary phase transition near 2006.4 K, which can be identified as a "strong" to "fragile" supercooled liquid or glass phase transition in UO 2. By fitting the oxygen diffusion constant with the Arrhenius equation, activation energies of 2.0 and 2.7 eV that we obtained were fairly close to the recommended values of 2.3 to 2.6 eV.

Original languageEnglish
Pages (from-to)360-369
Number of pages10
JournalNuclear Science and Engineering
Volume176
Issue number3
DOIs
Publication statusPublished - Mar 2014

    Fingerprint

ASJC Scopus subject areas

  • Nuclear Energy and Engineering

Cite this

Wang, X., Wu, B., Gao, F., Li, X., Sun, X., Khaleel, M. A., Akinlalu, A. V., & Liu, L. (2014). Molecular dynamics simulation of thermodynamic properties in uranium dioxide. Nuclear Science and Engineering, 176(3), 360-369. https://doi.org/10.13182/NSE13-14