Experimental and Numerical Stability Investigations on Natural Circulation Boiling Water Reactors
Experimental and Numerical Stability Investigations on Natural Circulation Boiling Water Reactors

Author: Christian Pablo Marcel

Publisher: IOS Press

Published: 2007

Total Pages: 160

ISBN-13: 1586038036

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In the design of novel nuclear reactors active systems are replaced by passive ones in order to reduce the risk of failure. For that reason natural circulation is being considered as the primary cooling mechanism in next generation nuclear reactor designs such as the natural circulation boiling water reactor (BWR). In such a reactor, however, the flow is not a controlled parameter but is dependent on the power. As a result, the dynamical behavior significantly differs from that in conventional forced circulation BWRs. For that reason, predicting the stability characteristics of these reactors has to be carefully studied. In this work, a number of open issues are investigated regarding the stability of natural circulation BWRs (e.g. margins to instabilities at rated conditions, interaction between the thermal-hydraulics and the neutronics, and the occurrence of flashing induced instabilities) with a strong emphasis on experimental evidence.

Experimental and Analytical Modeling of Natural Circulation and Forced Circulation BWRs
Experimental and Analytical Modeling of Natural Circulation and Forced Circulation BWRs

Author: Masahiro Furuya

Publisher: IOS Press

Published: 2006

Total Pages: 148

ISBN-13: 9781586036058

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20% of the Nuclear Power Plants are known as Boiling Water Reactors (BWRs). These BWRs have pumps that cool their reactor. In the design of new BWRs, ways to cool the core by a natural circulation flow, without pumps, also called natural circulation BWRs, are being considered. In these new systems, a chimney is installed on top of the core to increase natural circulation flow. A possible disadvantage of natural circulation BWRs might be their susceptibility to instabilities, which could then lead to both flow and power oscillations. The stability features of both natural circulation and forced circulation BWRs have been investigated thoroughly, using dedicated experimental setups, analytical models and numerical codes. We distinguish between pure thermal-hydraulic stability - where the fission power is assumed to be constant - and coupled thermalhydraulic-neutronic stability - where the two-phase mixture in the core influences the fission chain reaction...

An Experimental and Modelling Study of Natural-circulation Boiling Water Reactor Dynamics
An Experimental and Modelling Study of Natural-circulation Boiling Water Reactor Dynamics

Author: Róbert Zboray

Publisher: IOS Press

Published: 2002

Total Pages: 178

ISBN-13:

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Contents of this Doctoral Dissertation include: Understanding the linear stability characteristics of BWRs, Experiments on the stability of the Desire facility, Applications of the reducer-order model, Numerical analysis of the nonlinear dynamics of BWRs, Experiments on the nonlinear dynamics of natural-circulation two-phase flows, Experiments on the neutronic-thermalhydraulic stability, Conclusions and Discussion

Linear and Non-linear Stability Analysis in Boiling Water Reactors
Linear and Non-linear Stability Analysis in Boiling Water Reactors

Author: Alfonso Prieto Guerrero

Publisher: Woodhead Publishing

Published: 2018-10-15

Total Pages: 474

ISBN-13: 0081024460

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Linear and Non-Linear Stability Analysis in Boiling Water Reactors: The Design of Real-Time Stability Monitors presents a thorough analysis of the most innovative BWR reactors and stability phenomena in one accessible resource. The book presents a summary of existing literature on BWRs to give early career engineers and researchers a solid background in the field, as well as the latest research on stability phenomena (propagation phenomena in BWRs), nuclear power monitors, and advanced computer systems used to for the prediction of stability. It also emphasizes the importance of BWR technology and embedded neutron monitoring systems (APRMs and LPRMs), and introduces non-linear stability parameters that can be used for the onset detection of instabilities in BWRs. Additionally, the book details the scope, advantages, and disadvantages of multiple advanced linear and non linear signal processing methods, and includes analytical case studies of existing plants. This combination makes Linear and Non-Linear Stability Analysis in Boiling Water Reactors a valuable resource for nuclear engineering students focusing on linear and non-linear analysis, as well as for those working and researching in a nuclear power capacity looking to implement stability methods and estimate decay ratios using non-linear techniques. Explores the nuclear stability of Boiling Water Reactors based on linear and non-linear models Evaluates linear signal processing methods such as autoregressive models, Fourier-based methods, and wavelets to calculate decay ratios Proposes novel non-linear signal analysis techniques linked to non-linear stability indicators Includes case studies of various existing nuclear power plants as well as mathematical models and simulations

An Analytical and Experimental Investigation of Natural Circulation Transients in a Model Pressurized Water Reactor
An Analytical and Experimental Investigation of Natural Circulation Transients in a Model Pressurized Water Reactor

Author:

Publisher:

Published: 1987

Total Pages:

ISBN-13:

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Natural Circulation phenomena in a simulated PWR was investigated experimentally and analytically. The experimental investigation included determination of system characteristics as well as system response to the imposed transient under symmetric and asymmetric operations. System characteristics were used to obtain correlation for heat transfer coefficient in heat exchangers, system flow resistance, and system buoyancy heat. Asymmetric transients were imposed to study flow oscillation and possible instability. The analytical investigation encompassed development of mathematical model for single-phase, steady-state and transient natural circulation as well as modification of existing model for two-phase flow analysis of phenomena such as small break LOCA, high pressure coolant injection and pump coast down. The developed mathematical model for single-phase analysis was computer coded to simulate the imposed transients. The computer program, entitled ''Symmetric and Asymmetric Analysis of Single-Phase Flow (SAS), '' were employed to simulate the imposed transients. It closely emulated the system behavior throughout the transient and subsequent steady-state. Modifications for two-phase flow analysis included addition of models for once-through steam generator and electric heater rods. Both programs are faster than real time. Off-line, they can be used for prediction and training applications while on-line they serve for simulation and signal validation. The programs can also be used to determine the sensitivity of natural circulation behavior to variation of inputs such as secondary distribution and power transients.

Boiling Water Reactor Technology Status of the Art Report
Boiling Water Reactor Technology Status of the Art Report

Author: P. A. Lottes

Publisher:

Published: 1962

Total Pages: 194

ISBN-13:

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Information on heat transfer and hydraulics pertinent to the design and operation of boiling water reactor power plants is presented. The following areas of discussion are covered: heat transfer, two-phase density studies, two-phase pressure drop, critical heat flux and burnout, boiling stability, calculation procedures for boiling systems, and thermal-hydraulic design procedures for boiling water reactors.