Axial discontinuity factors for the nodal diffusion analysis of high conversion BWR cores

E. Fridman, S. Duerigen, Y. Bilodid, D. Kotlyar, E. Shwageraus

Research output: Contribution to journalArticlepeer-review

17 Scopus citations


High conversion LWRs concepts typically rely on a heterogeneous core configuration, where fissile zones are interspersed with fertile blanket zones in order to achieve a high conversion ratio. Modeling such a heterogeneous structure of these cores represents a significant challenge to the conventional reactor analysis methods. It was recently suggested to overcome such difficulties, in particular, for the case of axially heterogeneous reduced moderation BWRs, by introducing an additional set of discontinuity factors in axial direction at the interfaces between fissile and fertile fuel assembly zones. However, none of the existing nodal diffusion core simulators have the capability of accounting for discontinuity of homogeneous nodal fluxes in axial direction since the fuel composition of conventional LWRs is much more axially uniform. In this work, we modified the nodal diffusion code DYN3D by introducing such a capability. The new version of the code was tested on a series of reduced moderation BWR cases with Th-U233 and U-Pu-MA fuel. The library of few-group homogenized cross sections and the data required for the calculation of discontinuity factors were generated using the Monte Carlo transport code Serpent. The results obtained with the modified version of DYN3D were compared with the reference Monte Carlo solutions and were found to be in good agreement. The current analysis demonstrates that high conversion LWRs can in principle be modeled using existing nodal diffusion core simulators.

Original languageEnglish
Pages (from-to)129-136
Number of pages8
JournalAnnals of Nuclear Energy
StatePublished - 15 Jul 2013


  • Axial discontinuity factors
  • DYN3D
  • Few-group cross section generation
  • High conversion BWR
  • Monte Carlo
  • Serpent

ASJC Scopus subject areas

  • Nuclear Energy and Engineering


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