Nonlinear stability analysis with a novel BWR reduced order model

A. Dokhane, D. Hennig, R. Chawla, Rizwan-Uddin

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

BWR stability analysis at PSI, as at other research centres, is usually carried out employing complex system codes. These do not, however, allow detailed investigation of the complete manifold of possible solutions of the nonlinear differential equation set involved. A novel analytical, so-called reduced order, model for BWR stability is currently under development at PSI, in collaboration with the University of Illinois, Urbana-Champaign, USA. In a first step, the thermal-hydraulic model is used for separate two-phase density wave oscillation studies. Then, by adding a simple point-reactor model for neutron kinetics1 and a model for the fuel heat conduction dynamics, a study is conducted of the nuclear-coupled thermal-hydraulic dynamics in a BWR. Using the drift flux representation for two-phase flow, the reduced order model is employed in stability and bifurcation analyses, carried out using the bifurcation code BIFDD. The stability boundary (SB) and the nature of Poincaré-Andronov-Hopf bifurcation (PAH-B) are determined in two-dimensional space. A comparative study, between the use of the homogeneous equilibrium model (HEM) and the drift flux model (DFM), is carried out to investigate the effects of the DFM parameters - the void distribution parameter C0 and the drift velocity Vgj - on the SB, as well as on the nature of PAH bifurcation. This is, to the knowledge of the authors, the first analysis that systematically shows the effects of DFM parameters on the SB as well as on the nature of Hopf bifurcation. The SB is found to be sensitive to the used model. Both sub- and supercritical Hopf bifurcations are encountered. While it has been reported for a long time that the HEM is conservative in general, we show in this paper that this statement is not always correct.

Original languageEnglish (US)
Title of host publicationProceedings of the PHYSOR 2002 - International Conference on the New Frontiers of Nuclear Technology
Subtitle of host publicationReactor Physics, Safety and High-Performance Computing - The ANS 2002 RPD Topical Meeting
PublisherAmerican Nuclear Society
ISBN (Electronic)0894486721, 9780894486722
StatePublished - 2002
Event2002 International Conference on the New Frontiers of Nuclear Technology : Reactor Physics, Safety and High-Performance Computing, PHYSOR 2002 - Seoul, Korea, Republic of
Duration: Oct 7 2002Oct 10 2002

Publication series

NameProceedings of the PHYSOR 2002 - International Conference on the New Frontiers of Nuclear Technology : Reactor Physics, Safety and High-Performance Computing - The ANS 2002 RPD Topical Meeting

Conference

Conference2002 International Conference on the New Frontiers of Nuclear Technology : Reactor Physics, Safety and High-Performance Computing, PHYSOR 2002
Country/TerritoryKorea, Republic of
CitySeoul
Period10/7/0210/10/02

ASJC Scopus subject areas

  • Nuclear Energy and Engineering
  • Nuclear and High Energy Physics
  • Radiation
  • Safety, Risk, Reliability and Quality

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