Stability and Bifurcation Characteristics of a Forced Circulation BWR Using a Nuclear-Coupled Homogeneous Thermal-Hydraulic Model

Verma, Dinkar; Paul, Subhanker; Wahi, Pankaj

doi:10.1080/00295639.2017.1407593

Cited by 7 publications

(4 citation statements)

References 18 publications

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“…The fuel heat balance equation is written in analogy to that written for BWRs (Verma et al, 2018) as,…”

Section: Fuel Heat Transfer Modelingmentioning

confidence: 99%

“…These linear stability analyses only provide the system behavior in the vicinity of the stability boundaries and are valid for small perturbations in the system. However, recent studies on similar dynamical systems by Singh (2016, 2017); Verma et al (2018); Rahman and Singh (2018) reveal that the dynamical system like nuclear reactors possess various other stability behavior when investigations are made in a wide range of parametric space away from the linear stability threshold region. These behaviors are dominantly known as nonlinear stability characteristics which provide very good information about the system behavior with large perturbations.…”

Section: Introductionmentioning

confidence: 99%

“…B.4 we get:ρ(z, t) = 1 1 ρ in + b 1 (t) * z (B.5) Appendix B.3. Justification for velocity approximationIn case of a two-phase flow system with subcritical fluid, the mixture velocity is given byVerma et al (2018): dimensionalizing suitably and by further simplification, the above equation can be written as:w m (z, t) = w in (t) + N pch z (B.7)In analogy to the Eq. B.7, in case of a supercritical fluid, the velocity is approximated as:w(z, t) = w in (t) + A 1 N tpc (1 − ∆)z (B.8) Note that, there is no direct theoretical relation present for a supercritical fluid which can correlate the fluid velocity with heat flux as done in case of a subcritical fluid (Eq.…”

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confidence: 99%

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Development of a novel nodalized reduced order model for stability analysis of supercritical fluid in a heated channel

Singh

Paul

Singh

2019

International Journal of Thermal Sciences

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The nonlinear stability analysis of a supercritical light water reactor (SCLWR) is presented using a nuclear-coupled thermal-hydraulic reduced-order model. The analytical model is developed by coupling 1. the point-kinetics equations with one group of delayed neutrons, 2. the fuel heat transfer and 3. a 1-D reduced order model which represents the heat absorption phenomenon during the coolant flow. Unlike the existing studies, which are limited to linear stability analysis, the primary objective of the work is to present the detailed nonlinear dynamics of the SCLWR system. The said goal is achieved at two levels.The first level is the linear stability analysis wherein the linear stability boundaries are shown in two sets of parameter space namely the two intrinsic reactivity feedbacks (Doppler reactivity feedback and density reactivity feedback) and the pseudo-phase-change number and pseudo subcooling number. The parametric effects show the sensitivity of the linear stability boundaries with the system parameters. In the second level, to discuss the nonlinear characteristics of the system, two types of Hopf bifurcations (subcritical and supercritical) are studied with the help of first Lyapunov coefficients of the system. Multiple numerical simulations are performed to verify the resultant limit cycle behavior associated with these bifurcations. Moreover, the occurrence of the generalized Hopf bifurcation is shown which represents the bifurcation between the subcritical Hopf and the supercritical Hopf regions.Further, inside the stable region of the linear stability boundary, the saddle-node bifurcation is found which represents the location of the turning point and the threshold of the globally stable region of the system.

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“…The fuel heat balance equation is written in analogy to that written for BWRs (Verma et al, 2018) as,…”

Section: Fuel Heat Transfer Modelingmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

mentioning

confidence: 99%

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Development of a novel nodalized reduced order model for stability analysis of supercritical fluid in a heated channel

Singh

Paul

Singh

2019

International Journal of Thermal Sciences

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“…However, channel-to-channel interaction, flow, and heat distribution also complicate the real dynamics of these systems. This necessitates the development of reduced-order models (ROMs), which can deliver qualitative features of complex dynamics while keeping computational effort and complexity at a reasonable level [20][21][22]. Therefore, to replicate the real dynamics, several researchers adopted a reduced-order modeling approach along with appropriate approximation functions and, as a geometry reduction, single heated channels and configurations with a few parallel channel's geometries have been studied.…”

Section: Introductionmentioning

confidence: 99%

The Effect of Nodalization Schemes on the Stability Characteristics of a Three Heated Channels under Supercritical Flow Condition

Singh

Berrouk

Saeed³

2022

Energies

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The present analysis is aimed at conducting node sensitivity analysis on the thermal–hydraulic performance of supercritical fluid in a three parallel channel configuration system. The heated channel was divided into different nodes and is examined under wide-ranging operating conditions. Firstly, the heated channel was divided into two nodes, like the two-phase flow system. In the second case, based on the correlation between the fluid properties, the heated channel was divided into three regions: heavy, mixture, and supercritical fluids. Finally, the channel was divided into N-nodes. Post the nodalization analysis, a non-linear analysis of three parallel channels was carried out under varied heat flux conditions. The analytical approximation functions were developed to capture the fluid flow dynamics. These functions were used to capture each node’s density, enthalpy, and velocity profiles under a wide range of operating conditions. The different flow instability (density wave oscillations and static) characteristics were observed at low pseudo- and relatively high subcooling numbers. In the density wave oscillations regime, out-of-phase oscillations and limit cycles are observed. A co-dimension parametric analysis with numerical simulations was carried out to confirm the obtained non-linear characteristics. Such analysis for parallel channel systems under supercritical working fluid flow conditions is missing in the literature which is limited to only linear stability analysis. This analysis can help to improve heat and mass transfer for designing efficient heated channel systems.

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Dynamics and bifurcation characteristics of a boiling channel with forced circulation

Verma

Iyer

2023

Sādhanā

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Stability and Bifurcation Characteristics of a Forced Circulation BWR Using a Nuclear-Coupled Homogeneous Thermal-Hydraulic Model

Cited by 7 publications

References 18 publications

Development of a novel nodalized reduced order model for stability analysis of supercritical fluid in a heated channel

Development of a novel nodalized reduced order model for stability analysis of supercritical fluid in a heated channel

The Effect of Nodalization Schemes on the Stability Characteristics of a Three Heated Channels under Supercritical Flow Condition

Dynamics and bifurcation characteristics of a boiling channel with forced circulation

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