Parallel channel instabilities in boiling water reactor systems: boundary conditions for out of phase oscillations

Muñoz-Cobo, J.L.; Podowski, Michael Z.; Chiva, S.

doi:10.1016/s0306-4549(02)00024-5

Cited by 52 publications

(17 citation statements)

References 18 publications

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“…The models built in time domain permit either 0D analyses (Muñoz-Cobo et al, 2002;Schlichting et al, 2010), based on the analytical integration of conservation equations in the competing regions, or more complex but accurate 1D analyses (Ambrosini et al, 2000;Guo Yun et al, 2008;Zhang et al, 2009), by applying numerical solution techniques (finite differences, finite volumes or finite elements). In these models the steady-state is perturbed with small stepwise changes of some operating parameter simulating an actual transient, such as power increase in a real system.…”

Section: Theoretical Researches On Density Wave Oscillationsmentioning

confidence: 99%

“…The analytical model provided to theoretically study DWO instabilities is based on the work of Muñoz-Cobo et al (2002). Proper modifications have been considered to fit the modelling approach with steam generator tubes with imposed thermal power (representative of typical experimental facility conditions).…”

Section: Analytical Lumped Parameter Model: Fundamentals and Developmentmentioning

confidence: 99%

“…The model can apply to single boiling channel and two parallel channels configuration, suited both for instability investigation according to the specification of the respective boundary conditions: i. constant ∆P across the tube for single channel; ii. same ∆P(t) across the two channels (with constant total mass flow) for parallel channels (Muñoz-Cobo et al, 2002). …”

Section: Analytical Lumped Parameter Model: Fundamentals and Developmentmentioning

confidence: 99%

See 2 more Smart Citations

On Density Wave Instability Phenomena – Modelling and Experimental Investigation

Papini¹,

Cammi²,

Colombo³

et al. 2011

Two Phase Flow, Phase Change and Numerical Modeling

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The heat transfer and analysis on laser beam, evaporator coils, shell-and-tube condenser, two phase flow, nanofluids, complex fluids, and on phase change are significant issues in a design of wide range of industrial processes and devices. This book includes 25 advanced and revised contributions, and it covers mainly (1) numerical modeling of heat transfer, (2) two phase flow, (3) nanofluids, and (4) phase change. The first section introduces numerical modeling of heat transfer on particles in binary gas-solid fluidization bed, solidification phenomena, thermal approaches to laser damage, and temperature and velocity distribution. The second section covers density wave instability phenomena, gas and spray-water quenching, spray cooling, wettability effect, liquid film thickness, and thermosyphon loop. The third section includes nanofluids for heat transfer, nanofluids in minichannels, potential and engineering strategies on nanofluids, and heat transfer at nanoscale. The forth section presents time-dependent melting and deformation processes of phase change material (PCM), thermal energy storage tanks using PCM, phase change in deep CO2 injector, and thermal storage device of solar hot water system. The advanced idea and information described here will be fruitful for the readers to find a sustainable solution in an industrialized society.

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Section: Theoretical Researches On Density Wave Oscillationsmentioning

confidence: 99%

Section: Analytical Lumped Parameter Model: Fundamentals and Developmentmentioning

confidence: 99%

Section: Analytical Lumped Parameter Model: Fundamentals and Developmentmentioning

confidence: 99%

See 1 more Smart Citation

On Density Wave Instability Phenomena – Modelling and Experimental Investigation

Papini¹,

Cammi²,

Colombo³

et al. 2011

Two Phase Flow, Phase Change and Numerical Modeling

View full text Add to dashboard Cite

show abstract

“…In addition, the out-of-phase mode of DWOs cannot be accounted for by the single channel model. On the other hand, several studies (Lee and Pan, 1999;Muñoz-Cobo et al, 2000;Muñoz-Cobo et al, 2002;Muñoz-Cobo et al, 2004;Yun et al, 2008;Dutta and Doshi, 2009) were carried out on two-phase flow systems, which suggested that the MSB can significantly be affected by the radial power variations. Therefore, there is a need to develop a TH model for the simulation of flows in parallel channels in order to study both the in-phase and out-of-phase modes of oscillations in the SCWR.…”

Section: Introductionmentioning

confidence: 99%

Analysis of parallel channel instabilities in the CANDU supercritical water reactor

Dutta

Zhang

Jiang

2015

Annals of Nuclear Energy

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“…Normally, these subcritical modes would be damped out because the eigenvalues of these modes are less than one. However, when these subcritical flux modes are coupled with parallel-channel oscillations, sustained power oscillations can be realized [14] [15].…”

Section: Modes Of Bwr Instabilitiesmentioning

confidence: 99%

Predictive Methods for Stability Margin in BWR

Román¹

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iii This dissertation is dedicated to my mother, wherever she is now, who always gave me encouragement, love and support, my father raised me with infinite patience and advised me to obtain a degree in physics, my sister Pilar, example to follow both in the study and teaching and, especially my family, because this work has been done during the time I had to spend with my wife Marina, and my children Cecilia and Jose Andrés.I also want to thank my supervisors, Alberto Escrivá and José Luis Muñoz-Cobo without them this thesis would not have been possible. I also thank this work to José María Izquierdo Rocha who taught me to be rigorous and convinced me of the need for a thorough knowledge of nuclear engineering. To all my colleagues who have made me what I am today.Thanks to all v SUMMARY Power and flow oscillations in a BWR are very undesirable. One of the major concerns is to ensure, during power oscillations, compliance with GDC 10 and 12. GDC 10 requires that the reactor core be designed with appropriate margin to assure that specified acceptable fuel design limits will not be exceeded during any condition of normal operation, including the effects of anticipated operational occurrences. GDC 12 requires assurance that power oscillations which can result in conditions exceeding specified acceptable fuel design limits are either not possible or can be reliably and readily detected and suppressed.If the oscillation amplitude is large, before the scram occurs the fuel rods may experience periodic dry-out and rewetting, or if the oscillation is larger enough, extended dry-out.The Decay Ratio (DR) is the typical linear stability figure of merit. For analytical estimation of DR frequency domain codes are very useful. These types of codes are very fast and their results are very robust in comparison with time domain codes, whose results may be dependent on numeric scheme and nodalization. The only drawback of frequency domain is that you are limited to the linear domain; however, because of regulatory requirements imposed by GDC-12, reactors must remain stable and, thus, reactors always operate in the linear domain.LAPUR is a frequency domain stability code that contains a mathematical description of the core of a boiling water reactor. It solves the steady state governing equations for the coolant and fuel, and the dynamic equations for the coolant, fuel and the neutron field in the frequency domain. Several improvements have been performed to the current version of the code, LAPUR5, in order to upgrade it for use with new fuel design types. The channel geometry has been changed from constant area to variable area. The local losses due to the spacers and contractions along the flow path have been upgraded to use industry standard correlations. This new version is LAPUR 6.In this work, in order to check the correct implementation of these changes, a two-fold LAPUR 6 validation has been performed: vi First, an exhaustive validation of the models implemented has been performed, comparing single channels LAPUR 6 outputs...

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Parallel channel instabilities in boiling water reactor systems: boundary conditions for out of phase oscillations

Cited by 52 publications

References 18 publications

On Density Wave Instability Phenomena – Modelling and Experimental Investigation

On Density Wave Instability Phenomena – Modelling and Experimental Investigation

Analysis of parallel channel instabilities in the CANDU supercritical water reactor

Predictive Methods for Stability Margin in BWR

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