Modelling the thermal conductivity of (UxTh1−x)O2 and (UxPu1−x)O2

The degradation of thermal conductivity due to the non-uniform cation lattice of (UxTh1−x)O2 and (UxPu1−x)O2 solid solutions has been investigated by molecular dynamics, using the non-equilibrium method, from 300 to 2000 K. Degradation of thermal conductivity is predicted in (UxTh1−x)O2 and (UxPu1−x...

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Bibliographic Details
Published inJournal of nuclear materials Vol. 466; no. C; pp. 29 - 35
Main Authors Cooper, M.W.D., Middleburgh, S.C., Grimes, R.W.
Format Journal Article
LanguageEnglish
Published United States Elsevier B.V 01.11.2015
Elsevier
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Summary:The degradation of thermal conductivity due to the non-uniform cation lattice of (UxTh1−x)O2 and (UxPu1−x)O2 solid solutions has been investigated by molecular dynamics, using the non-equilibrium method, from 300 to 2000 K. Degradation of thermal conductivity is predicted in (UxTh1−x)O2 and (UxPu1−x)O2 as compositions deviate from the pure end members: UO2, PuO2 and ThO2. The reduction in thermal conductivity is most apparent at low temperatures where phonon-defect scattering dominates over phonon–phonon interactions. The effect is greater for (UxTh1−x)O2 than for (UxPu1−x)O2 due to the greater mismatch in cation size and mass. Parameters for analytical expressions have been developed that describe the predicted thermal conductivities over the full temperature and compositional ranges. These expressions may be used in higher level fuel performance codes.
Bibliography:USDOE
EP/I036400/1; AC52-06NA25396
LA-UR-15-24388
ISSN:0022-3115
1873-4820
DOI:10.1016/j.jnucmat.2015.07.022