Effects of grain size and porosity on cladding failure in high-burnup UO2: A sensitivity and uncertainty study

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Abstract

Isotopic taggants are being studied to aid in the provenance assessment of nuclear materials. However, these taggants must be selected such that they do not adversely affect fuel performance during normal operation or accident scenarios. Taggants are known to affect the fuel's grain size and porosity. In the work described in this paper, the BISON fuel performance code was used to assess the potential effects of taggants (i.e., grain size and porosity) on fuel rod behavior and cladding failure during a high-burnup, large-break loss-of-coolant accident. Here, 281 individual fuel rods from the same reactor core were modeled for a sensitivity study, a parametric study, and uncertainty quantification. The cladding failure predictions often exhibited stochastic behavior. After additional study, it was found that the cladding failure model is highly sensitive to residual error inherent to numerical approximation solvers. Some strategies to mitigate this sensitivity are discussed. The study found no relationship between known taggant effects and cladding failure status. However, taggants were found to affect the time and location of failure in certain rods. Future work to continue investigating and validating these findings is briefly discussed.

Original languageEnglish
Article number114484
JournalNuclear Engineering and Design
Volume445
DOIs
StatePublished - Dec 15 2025

Funding

This work was supported by the U.S. Department of Energy, National Nuclear Security Administration, Office of Defense Nuclear Nonproliferation R&D. The BISON input files used in this work were provided by the NEAMS program. All simulations were performed on INL HPC's Sawtooth cluster. The authors also wish to thank Cade Hilger for reviewing and providing feedback of this paper.

Keywords

  • Doped UO
  • Fuel performance
  • Nuclear forensics
  • Nuclear fuel
  • Sensitivity and uncertainty

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