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Title: Lattice thermal conductivity of UO{sub 2} using ab-initio and classical molecular dynamics

We applied the non-equilibrium ab-initio molecular dynamics and predict the lattice thermal conductivity of the pristine uranium dioxide for up to 2000 K. We also use the equilibrium classical molecular dynamics and heat-current autocorrelation decay theory to decompose the lattice thermal conductivity into acoustic and optical components. The predicted optical phonon transport is temperature independent and small, while the acoustic component follows the Slack relation and is in good agreement with the limited single-crystal experimental results. Considering the phonon grain-boundary and pore scatterings, the effective lattice thermal conductivity is reduced, and we show it is in general agreement with the sintered-powder experimental results. The charge and photon thermal conductivities are also addressed, and we find small roles for electron, surface polaron, and photon in the defect-free structures and for temperatures below 1500 K.
Authors:
 [1] ;  [2] ;  [3] ;  [1] ;  [2]
  1. Department of Mechanical Engineering, University of Michigan, Ann Arbor, Michigan 48109 (United States)
  2. (Korea, Republic of)
  3. Division of Advanced Nuclear Engineering, Pohang University of Science and Technology, Pohang 790-784 (Korea, Republic of)
Publication Date:
OSTI Identifier:
22271150
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 115; Journal Issue: 12; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; CRYSTAL LATTICES; ELECTRIC CURRENTS; ELECTRONS; GRAIN BOUNDARIES; MOLECULAR DYNAMICS METHOD; MONOCRYSTALS; PHONONS; PHOTONS; POWDERS; SURFACES; TEMPERATURE DEPENDENCE; TEMPERATURE RANGE 1000-4000 K; THERMAL CONDUCTIVITY; URANIUM DIOXIDE