Development of FEMAXI-ATF for analyzing PCMI behavior of SiC cladded fuel under power ramp conditions

Yoshihiro Kubo*, Akifumi Yamaji

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


FEMAXI-ATF is being developed for fuel performance modeling of SiC cladded UO2 fuel with focuses on modeling pellet-cladding mechanical interactions (PCMI). The code considers probability distributions of mechanical strengths of monolithic SiC (mSiC) and SiC fiber reinforced SiC matrix composite (SiC/SiC), while it models pseudo-ductility of SiC/SiC and propagation of cladding failures across the wall thickness direction in deterministic manner without explicitly modeling cracks based on finite element method in one-dimensional geometry. Some hypothetical BWR power ramp conditions were used to test sensitivities of different model parameters on the analyzed PCMI behavior. The results showed that propagation of the cladding failure could be modeled by appropriately reducing modulus of elasticities of the failed wall element, so that the mechanical load of the failed element could be re-distributed to other intact elements. The probability threshold for determination of the wall element failure did not have large influence on the predicted power at failure when the threshold was varied between 25 % and 75 %. The current study is still limited with respect to mechanistic modeling of SiC failure as it only models the propagation of the cladding wall element failure across the homogeneous continuum wall without considering generations and propagations of cracks.

Original languageEnglish
Pages (from-to)846-854
Number of pages9
JournalNuclear Engineering and Technology
Issue number3
Publication statusPublished - 2024 Mar


  • Accident tolerant fuel (ATF)
  • Fuel performance analysis
  • PCMI
  • Power ramp
  • SiC cladded fuel

ASJC Scopus subject areas

  • Nuclear Energy and Engineering


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