Thermal conductivity and energetic recoils in UO2 using a many-body potential model

MJ Qin and MWD Cooper and EY Kuo and MJD Rushton and RW Grimes and GR Lumpkin and SC Middleburgh, JOURNAL OF PHYSICS-CONDENSED MATTER, 26, 495401 (2014).

DOI: 10.1088/0953-8984/26/49/495401

Classical molecular dynamics simulations have been performed on uranium dioxide (UO2) employing a recently developed many-body potential model. Thermal conductivities are computed for a defect free UO2 lattice and a radiation-damaged, defect containing lattice at 300 K, 1000 K and 1500 K. Defects significantly degrade the thermal conductivity of UO2 as does the presence of amorphous UO2, which has a largely temperature independent thermal conductivity of similar to 1.4 Wm(-1) K-1. The model yields a pre-melting superionic transition temperature at 2600 K, very close to the experimental value and the mechanical melting temperature of 3600 K, slightly lower than those generated with other empirical potentials. The average threshold displacement energy was calculated to be 37 eV. Although the spatial extent of a 1 keV U cascade is very similar to those generated with other empirical potentials and the number of Frenkel pairs generated is close to that from the Basak potential, the vacancy and interstitial cluster distribution is different.

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