Thermophysical properties of urania-zirconia (U,Zr)O2 mixed oxides by molecular dynamics

Molecular dynamics simulations were used to investigate the thermophysical properties of (U,Zr)O2 between 300 K and 3500 K. For compositions with 25% UO2, which are in the cubic fluorite phase, is similar to that of UO2. A superionic transition is observed in cubic (U,Zr)O2 at temperatures between 1...

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Bibliographic Details
Published in:Journal of nuclear materials 2020-01, Vol.528, p.151876, Article 151876
Main Authors: Frost, D.G., Galvin, C.O.T., Cooper, M.W.D., Obbard, E.G., Burr, P.A.
Format: Article
Language:English
Subjects:
Accident conditions
Fluorite
Heat conductivity
Heat transfer
Mixed oxides
Molecular dynamics
Nuclear fuel
NUCLEAR FUEL CYCLE AND FUEL MATERIALS
Oxides
Specific heat
Temperature
Thermal conductivity
Thermal expansion
Thermophysical properties
UO2
Uranium dioxide
Zirconia
Zirconium dioxide
Zirconium oxides
ZrO2
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Summary:Molecular dynamics simulations were used to investigate the thermophysical properties of (U,Zr)O2 between 300 K and 3500 K. For compositions with 25% UO2, which are in the cubic fluorite phase, is similar to that of UO2. A superionic transition is observed in cubic (U,Zr)O2 at temperatures between 1500 K and 3000 K, occurring at progressively lower temperatures with increasing ZrO2 content. The heat capacity of these mixed oxides increases from 80 J/mol.K up to 130 J/mol.K at temperatures relevant to accident conditions, possibly retarding temperature increase in fuels with a significant pellet-clad bonding layer.
ISSN:0022-3115
1873-4820
DOI:10.1016/j.jnucmat.2019.151876