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Title: Atomistic study of porosity impact on phonon driven thermal conductivity: Application to uranium dioxide

We present here an analytical method, based on the kinetic theory, to determine the impact of defects such as cavities on the thermal conductivity of a solid. This approach, which explicitly takes into account the effects of internal pore surfaces, will be referred to as the Phonon Interface THermal cONductivity (PITHON) model. Once exposed in the general case, this method is then illustrated in the case of uranium dioxide. It appears that taking properly into account these interface effects significantly modifies the temperature and porosity dependence of thermal conductivity with respect to that issued from either micromechanical models or more recent approaches, in particular, for small cavity sizes. More precisely, it is found that if the mean free path appears to have a major effect in this system in the temperature and porosity distribution range of interest, the variation of the specific heat at the surface of the cavity is predicted to be essential at very low temperature and small sizes for sufficiently large porosity.
Authors:
;  [1] ;  [2]
  1. Institut de Radioprotection et de Sûreté Nucléaire, IRSN, Bat. 702, CE Cadarache, BP3-13115 Saint Paul-Lez-Durance Cedex (France)
  2. Aix-Marseille Université, CNRS, CINaM UMR 7325, 13288 Marseille (France)
Publication Date:
OSTI Identifier:
22275788
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 115; Journal Issue: 3; 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; DEFECTS; INTERFACES; MEAN FREE PATH; PHONONS; POROSITY; SOLIDS; SPECIFIC HEAT; TEMPERATURE RANGE 0000-0013 K; THERMAL CONDUCTIVITY; URANIUM DIOXIDE