Development of Method to Determine Instability Threshold with RETRAN Code

Fumimasa Araya, Masashi Hirano, Kazuo Yoshida, Kiyoshi Matsumoto, Masao Yokobayashi, Atsuo Kohsaka

Research output: Contribution to journalArticlepeer-review

1 Citation (Scopus)


Neutron flux oscillation event occurred at LaSalle-2 (BWR5) on March 9, 1988 which arised issues such as why the event occurred and what major differences between LaSalle-2 and other BWRs were in view of the BWR stability. In order to resolve the issues, a method to determine instability threshold was developed at Japan Atomic Energy Research Institute (JAERI) by using the transient thermal-hydraulic analysis code RETRAN which was developed at Electric Power Research Institute (EPRI). The validity of the method was confirmed by parametric studies and thermal-hydraulic experiment analyses. Using the method, the instability boundary for in-phase oscillation was obtained. For out -of-phase oscillation, however, it was found that the instability boundary could not be determined in nature due to the limitation from the point reactor kinetics model.

Original languageEnglish
Pages (from-to)879-888
Number of pages10
JournalNippon Genshiryoku Gakkaishi/Journal of the Atomic Energy Society of Japan
Issue number9
Publication statusPublished - 1992
Externally publishedYes


  • BWR type reactors
  • computer codes
  • in-phase oscillation
  • instability
  • oscillation modes
  • out-of-phase oscillation
  • point reactor kinetics
  • transient thermal-hydraulics

ASJC Scopus subject areas

  • Nuclear Energy and Engineering


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