A Phase-Field Description of Brittle Crack Propagation in Nuclear Fuels - Archive ouverte HAL
Communication Dans Un Congrès Année : 2018

A Phase-Field Description of Brittle Crack Propagation in Nuclear Fuels

Thomas Helfer
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Olivier Fandeur

Résumé

The fuel element of most Pressurized Water Reactors are made of a stack of uranium dioxide pellets where heat-generating nuclear fission reactions take place and a zirconium alloy cladding which constitutes a guarantee against dispersion of fissile material and fission products. Modelling the in-reactor behaviour of such fuel elements is made complex by the myriad of coupled, nonlinear, chemical, mechanical, thermal and microstructural changes that take place within the fuel. From the mechanical point of view alone, various contributions must be taken into account, such as brittle fracture of the fuel pellets at reactor start-up, thermally and radiation induced viscoplasticity, swelling due to fission products, pellet-cladding mechanical interaction (PCMI), etc. The cracking of pressurised water reactor fuel pellets has the two main consequences on the macroscopic mechanical behaviour of the fuel rod: firstly, to relieve the stress in the pellet, upon which the majority of the mechanical and physico-chemical phenomena are dependent, and secondly, to lead to pellet fragmentation. Taking fuel cracking into account is therefore necessary to adequately predict the mechanical loading of the cladding during the course of an irradiation. Simulating these phenomena is challenging both from a numerical standpoint and from the point of view of the physical phenomena involved. As a result of this, advanced and robust numerical techniques are necessary, especially in large-scale fuel performance. Our presentation will focus on the treatment of the fuel cracking through a phase-field approach using the finite element solver Cast3M, developed by CEA, and also the first steps to deal with unstable crack propagation in a quasi-static point of view
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Dates et versions

hal-03110319 , version 1 (14-01-2021)

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  • HAL Id : hal-03110319 , version 1

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Thomas Helfer, Olivier Fandeur. A Phase-Field Description of Brittle Crack Propagation in Nuclear Fuels. WCCM XIII - the 13th World Congress on Computational Mechanics, 2018, New York, United States. ⟨hal-03110319⟩
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