title: Thermophysical properties and oxygen transport in (Thx,Pu1-x)O2.
abstract: Using Molecular Dynamics, this paper investigates the thermophysical properties and oxygen transport of (Thx,Pu1-x)O2(0 ≤ x ≤ 1) between 300-3500 K. In particular, the superionic transition is investigated and viewed via the thermal dependence of lattice parameter, linear thermal expansion coefficient, enthalpy and specific heat at constant pressure. Oxygen diffusivity and activation enthalpy are also investigated. Below the superionic temperature an increase of oxygen diffusivity for certain compositions of (Thx,Pu1-x)O2compared to the pure end members is predicted. Oxygen defect formation enthalpies are also examined, as they underpin the superionic transition temperature and the increase in oxygen diffusivity. The increase in oxygen diffusivity for (Thx,Pu1-x)O2is explained in terms of lower oxygen defect formation enthalpies for (Thx,Pu1-x)O2than PuO2and ThO2, while links are drawn between the superionic transition temperature and oxygen Frenkel disorder.
authors: Department of Materials, Imperial College London, London, SW7 2AZ, UK.
authors: C O T
authors: CO
authors: Galvin
authors: Materials Science and Technology Division, Los Alamos National Laboratory, P.O. Box 1663, Los Alamos, New Mexico 87545, USA.
authors: M W D
authors: MW
authors: Cooper
authors: Department of Materials, Imperial College London, London, SW7 2AZ, UK.
authors: M J D
authors: MJ
authors: Rushton
authors: Department of Materials, Imperial College London, London, SW7 2AZ, UK.
authors: R W
authors: RW
authors: Grimes