Structural dynamics of Schottky and Frenkel defects in ThO2: a density-functional theory study

Samuel Moxon,E Lora Da Silva,Joshua S Tse,Robert M Harker,A Togo,Marco Molinari,Jonathan Skelton,David J Cooke,Stephen C Parker,Mark T Storr,Joseph Flitcroft

doi:10.1039/d1ta10072f

Abstract

First-principles modelling is used to study the intrinsic Schottky and Frenkel defects in ThO2 and their impact on the structural dynamics and thermal transport.

Highlights

A complete understanding of the thermophysical properties of ThO2 is critical to controlling fuel performance at the high temperatures and pressures in nuclear reactors
Standard density-functional theory (DFT) does not take into account the effect of temperature
An experimental lattice parameter of 5.5828 Aat 0 K can be extrapolated from the empirical function of Tyagi and Mathews,[51] which is still higher than our calculated value. This indicates that the underestimation of the lattice parameter may be due to the DFT functional used

Summary

Introduction

A complete understanding of the thermophysical properties of ThO2 is critical to controlling fuel performance at the high temperatures and pressures in nuclear reactors. The energy release associated with nuclear events in reactors can generate large nonequilibrium concentrations of defects, and these can have a direct in uence on the physical properties. Since experimental measurements on ThO2 are challenging, computational modelling using rst-principles methods such as density-functional theory (DFT), in conjunction with modern high-performance computing (HPC), plays a key role in contemporary nuclear research, when atomistic or nanoscale details are required.[5]. Under ambient conditions ThO2 is non-magnetic with a cubic structure in the Fm3m space group 62) begins at 20–30 GPa6–9 and completes at above 1000 K and 30 GPa.[11] As Mott insulators, the thermal transport in ThO2 and other

Methods

Results

Conclusion