Molecular dynamics simulation of dislocations in uranium dioxide

• Published in: Journal of nuclear materials Vol. 443; no. 1-3; pp. 359 - 365
• Main Authors: Fossati, Paul, Van Brutzel, Laurent, Devincre, Benoît
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01-11-2013; Elsevier
• Subjects: Applied sciences; Burgers vector; Condensed Matter; Controled nuclear fusion plants; Dislocation mobility; Dislocations; Disorders; Energy; Energy. Thermal use of fuels; Exact sciences and technology; Fission nuclear power plants; Fuels; Installations for energy generation and conversion: thermal and electrical energy; Materials Science; Mathematical analysis; Molecular dynamics; Molecular structure; Nuclear fuels; Physics; Preparation and processing of nuclear fuels; Simulation; Molecular dynamics; Nuclear fuel; Uranium; Uranium dioxide; Reactor core; Nuclear reactor
• ISSN: 0022-3115; 1873-4820
• DOI: 10.1016/j.jnucmat.2013.07.059

The plasticity of the fluorite structure in UO2 is investigated with molecular dynamics simulation and empirical potential. The stacking fault energies and the dislocation core structures with Burgers vector a2〈110〉 are systematically calculated. All dislocation core structures show a significant increase of the oxygen sub-lattice disorder at temperatures higher than 1500K. The threshold stress for dislocation glide is found to decrease with increasing temperature but its values is always very high, several GPa at 0K and several hundred of MPa at 2000K. A relation between the dislocation mobility dependence with temperature and the increase of the oxygen sub-lattice disorder in the dislocation cores is established.