Oxygen self-diffusion in ThO2 under pressure: connecting point defect parameters with bulk properties

MWD Cooper and ME Fitzpatrick and LH Tsoukalas and A Chroneos, MATERIALS RESEARCH EXPRESS, 3, 65501 (2016).

DOI: 10.1088/2053-1591/3/6/065501

ThO2 is a candidate material for use in nuclear fuel applications and as such it is important to investigate its materials properties over a range of temperatures and pressures. In the present study molecular dynamics calculations are used to calculate elastic and expansivity data. These are used in the framework of a thermodynamic model, the cB Omega model, to calculate the oxygen self-diffusion coefficient in ThO2 over a range of pressures (-10-10 GPa) and temperatures (300-1900 K). Increasing the hydrostatic pressure leads to a significant reduction in oxygen self-diffusion. Conversely, negative hydrostatic pressure significantly enhances oxygen self-diffusion.

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