A thermodynamic approach of the mechano-chemical coupling during the oxidation of uranium dioxide

Nicolas Creton (1) , Virgil Optasanu (1) , Tony Montesin (1) , Sébastien Garruchet (1) , Lionel Desgranges (2)

1 ICB - Laboratoire Interdisciplinaire Carnot de Bourgogne
2 LM2C - Laboratoire de Modélisation Multi-échelles des Combustibles

The aim of the present work is to introduce a thermodynamic model to describe the growth of an oxide layer on a metallic substrate. More precisely, this paper offers a study of oxygen dissolution into a solid, and its consequences on the apparition of mechanical stresses. They strongly influence the oxidation processes and may be, in some materials, responsible for cracking. To realize this study, mechanical considerations are introduced into the classical diffusion laws. Simulations were made for the particular case of uranium dioxide, which undergoes the chemical fragmentation. According to our simulations, the hypothesis of a compression stress field into the oxidised UO2 compound near the internal interface is consistent with the interpretation of the mechanisms of oxidation observed experimentally.

Mots clés: modelling; mechano-chemical coupling; oxidation

Domaines: Chimie-Physique [physics.chem-ph]; Mécanique des matériaux [physics.class-ph]; Mécanique des matériaux [physics.class-ph]

Nicolas Creton, Virgil Optasanu, Tony Montesin, Sébastien Garruchet, Lionel Desgranges. A thermodynamic approach of the mechano-chemical coupling during the oxidation of uranium dioxide. Defect and Diffusion Forum, 2009, Defect and Diffusion Forum, 289-292, pp.447-454. ⟨10.4028/www.scientific.net/DDF.289-292.447⟩. ⟨hal-00416172⟩