TY - GEN
T1 - Nonlinear stability analysis with a novel BWR reduced order model
AU - Dokhane, A.
AU - Hennig, D.
AU - Chawla, R.
AU - Rizwan-Uddin,
N1 - The authors would like to express their appreciation to J.F. Stubbins, Head of the Department of Nuclear, Plasma, and Radiological Engineering at the University of Illinois (UIUC), for the warm hospitality received by the first author during his stay at UIUC. BWR stability research at PSI forms part of the nuclear safety analysis project STARS at PSI, and the authors would like to thank M.A Zimmermann, the STARS project manager, for support and discussions. This work has been partly sponsored by the Swiss Federal Nuclear Safety Inspectorate.
PY - 2002
Y1 - 2002
N2 - 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.
AB - 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.
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M3 - Conference contribution
AN - SCOPUS:84897917470
T3 - Proceedings 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
BT - Proceedings of the PHYSOR 2002 - International Conference on the New Frontiers of Nuclear Technology
PB - American Nuclear Society
T2 - 2002 International Conference on the New Frontiers of Nuclear Technology : Reactor Physics, Safety and High-Performance Computing, PHYSOR 2002
Y2 - 7 October 2002 through 10 October 2002
ER -