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Modèle numérique micro-mécanique d'agrégat polycristallin pour le comportement des combustibles oxydes

Julien Pacull 1, 2 
2 LSC - Laboratoire de Simulation du Comportement des Combustibles
SESC - Service d'Etudes de Simulation du Comportement du combustibles : DEN/DEC/SESC
Abstract : In Pressurized Water Reactors (PWR, fuel is generally composed of uranium dioxide pellets piled up within a zirconium tubular cladding. Modeling of fuel behavior in nominal and accidental conditions requires multi-scale models in order to take into account both the thermo-mechanical behavior of the pellets and the effects of fission gases. Recent development of micromecanical tools of simulation has improved coupling possibilities.

Our study proposes to set a full micromechanical model for uranium dioxide dealing with both mechanics and fission products transport at the scale of a polycristalline aggregate. Both the effective behavior of the RVE and stress localization effects are studied. Hydrostatic pressure, which directly controls the diffusion of fission gases, is given a particular focus.
The numerical robustness of results is also debated in terms of mesh refinement. A series of simulations leads to a satisfying compromise between accuracy and calculation time.

A study compares experimental measurement of intergranular crack opening and simulation results performed using cohesive models. The micromecanical behavior of uranium dioxide during irradiation is analysed by submitting the polycristalline RVE to transient irradiation. The local stress distribution leads to a debate on the consequences of intergranular strain incompatibility on fission gases diffusion.
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Submitted on : Wednesday, July 25, 2012 - 9:57:55 PM
Last modification on : Tuesday, October 19, 2021 - 10:59:08 PM
Long-term archiving on: : Friday, October 26, 2012 - 3:40:10 AM


  • HAL Id : tel-00720837, version 1


Julien Pacull. Modèle numérique micro-mécanique d'agrégat polycristallin pour le comportement des combustibles oxydes. Mécanique des solides [physics.class-ph]. Université de Provence - Aix-Marseille I, 2011. Français. ⟨tel-00720837⟩



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