Oxygen diffusion in relation to p-type doping in uranium dioxide

• Published in: Journal of nuclear materials Vol. 400; no. 2; pp. 112 - 118
• Main Authors: Garcia, P., Fraczkiewicz, M., Davoisne, C., Carlot, G., Pasquet, B., Baldinozzi, G., Siméone, D., Petot, C.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 15.05.2010; Elsevier
• Subjects: Applied sciences; Condensed Matter; Controled nuclear fusion plants; Doping; Electrical conductivity; Electrical resistivity; 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; Interstitials; Materials Science; Migration; Nuclear fuels; Physics; Point defects; Preparation and processing of nuclear fuels; Resistivity; Secondary ion mass spectrometry; Electrical conductivity; Uranium; Impurity; Point defect; Concentration effect; Nuclear fuel; Diffusion coefficient; Diffusion; Uranium dioxide; Nuclear reactor; Tracers
• ISSN: 0022-3115; 1873-4820
• DOI: 10.1016/j.jnucmat.2010.02.019

In this paper we show how electrical conductivity and intrinsic oxygen diffusion coefficient measurements can be used in conjunction to further our understanding of oxygen related point defects in UO 2. Electrical conductivity measurements have enabled an estimate to be made of the positive charge carrier concentration in two sets of samples containing different levels of doping agents. The gas–solid isotopic exchange method was then used to load the samples with 18O tracer atoms the concentration profile of which were subsequently characterised using SIMS and chromatic confocal microscopy. At the oxygen potential and temperature studied (750 °C), application of point-defect theory to our experimental results points to oxygen migration proceeding via an interstitial mechanism and to the fact that impurities control the concentration of negatively charged point defects responsible for atomic migration.