Application of Weibull fracture strength distributions to modelling crack initiation behaviour in nuclear fuel pellets using peridynamics

L. D. Jones, T. A. Haynes, G. Rossiter, M. R. Wenman

Research output: Contribution to journalArticlepeer-review

Abstract

The thermomechanical behaviour of uranium dioxide nuclear fuel pellets irradiated in a pressurised water reactor has been simulated using a two-dimensional application of bond-based peridynamics implemented in the Abaqus commercial finite element software. Near-surface bond failure, and hence crack initiation, were modelled assuming a probabilistic (variable) failure strain described by a Weibull distribution – with bond failure, and hence crack propagation, in the bulk of the fuel pellets modelled assuming a deterministic (fixed) failure strain. The measured dependency of the number of radial pellet cracks on heat generation rate per unit length – which we show cannot be reproduced by the common assumption in pellet modelling of a deterministic failure strain throughout the pellet volume – was accurately predicted when a size-scaled Weibull distribution with a modulus of 5 was used. However, this low modulus value was associated with the prediction of some cracks initiating away from the pellet surface, which is unphysical. Use of a Weibull modulus of 10 avoided this simulation artefact while still reproducing the experimentally observed dependency with reasonable accuracy.
Original languageEnglish
Article number154087
JournalJournal of Nuclear Materials
Volume572
Early online date13 Oct 2022
DOIs
Publication statusE-pub ahead of print - 13 Oct 2022

Keywords

  • Ceramic material
  • Crack mechanics and peridynamics
  • Fracture
  • Thermomechanical process

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