Specific Aspects of Internal Corrosion of Nuclear Clad Made of Zircaloy

Jean-Baptiste Minne (1) , Lionel Desgranges (2) , Virgil Optasanu (3) , Nathalie Largenton (4) , Laura Raceanu (3) , Tony Montesin (3)

1 EDF R&D MMC - Matériaux et Mécanique des Composants
2 LM2C - Laboratoire de Modélisation Multi-échelles des Combustibles
3 ICB - Laboratoire Interdisciplinaire Carnot de Bourgogne
4 EDF R&D - EDF R&D

In PWR, the Zircaloy based clad is the first safety barrier of the fuel rod, it must prevent the dispersion of the radioactive elements, which are formed by fission inside the UO2 pellets filling the clad. We focus here on internal corrosion that occurs when the clad is in tight contact with the UO2 pellet. In this situation, with temperature of 400 °C on the internal surface of the clad, a layer of oxidised Zircaloy is formed with a thickness ranging from 5 to 15 µm. In this paper, we will underline the specific behaviour of this internal corrosion layer compared to wet corrosion of Zircaloy. Simulations will underline the differences of stress field and their influences on corresponding dissolved oxygen profiles. The reasons for these differences will be discussed as function of the mechanical state at inner surface of the clad which is highly compressed. Differences between mechanical conditions generated by an inner or outer corrosion of the clad are studied and their influences on the diffusion phenomena are highlighted.

Mots clés: Clad Corrosion; Stress-Diffusion Coupling; Zircaloy Oxidation

Domaines: Matériaux et structures en mécanique [physics.class-ph]; Matériaux et structures en mécanique [physics.class-ph]; Matériaux

Jean-Baptiste Minne, Lionel Desgranges, Virgil Optasanu, Nathalie Largenton, Laura Raceanu, et al.. Specific Aspects of Internal Corrosion of Nuclear Clad Made of Zircaloy. Defect and Diffusion Forum, 2012, 223-225, pp.227-232. ⟨10.4028/www.scientific.net/DDF.323-325.227⟩. ⟨hal-00771497⟩