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arXiv · 2609.29236

3D modelling of strain concentration due to PCI within the fuel code ALCYONE

J. Sercombe·Jérôme Julien·Frederic Michel·Bruno Michel·Éric Fédérici
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Abstract

In this paper, the 3D scheme of the fuel code ALCYONE is applied to a database consisting of more than 50 base irradiations and ramp tests performed on rods with UO 2 , MOX or Cr-doped UO 2 fuels and Zy4 or M5__ cladding tubes with burn-ups up to 70 GWd/tU. The ability of the 3D scheme to predict the behaviour of a single fuel pellet -cladding element situated at the maximum Linear Heat Rate (LHR) during ramp testing is demonstrated by comparing the following experimental and calculated data: residual clad diameter after base irradiation and ramp test, height of inter-pellet and mid-pellet ridges after base irradiation and ramp test, dish filling after ramp test. In the second part of the paper, 3D simulations that catch the stress -strain localization at the triple point are presented. It is shown that the stress-strain concentration occurs only at the end of the power transient and is quickly relaxed by pellet and clad creep.

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J. Sercombe, Jérôme Julien, Frederic Michel, Bruno Michel, Éric Fédérici. 2026-09-24. 3D modelling of strain concentration due to PCI within the fuel code ALCYONE. https://arxiv.org/abs/2609.29236

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