Capability of RELAP5 code to simulate the thermal-hydraulic characteristics of open natural circulation

Hou, Xiaofan; Sun, Zhongning; Lei, Wenjing

doi:10.1016/j.anucene.2017.06.010

Cited by 41 publications

(8 citation statements)

References 20 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…A few notable examples among those codes used for thermohydraulic analysis are THERMIT, TREMOLO, RELAP5, RETRAN, CATHARE, TRACE, etc. [95][96][97][98][99][100]. The basic equation of multiphase flow used in reactor safety analysis is in the following form [101].…”

Section: Two-phase Flowmentioning

confidence: 99%

An Overview of the Numerical Approaches to Water Hammer Modelling: The Ongoing Quest for Practical and Accurate Numerical Approaches

Pal

Hanmaiahgari

Karney

2021

Water

View full text Add to dashboard Cite

Here, recent developments in the key numerical approaches to water hammer modelling are summarized and critiqued. This paper summarizes one-dimensional modelling using the finite difference method (FDM), the method of characteristics (MOC), and especially the more recent finite volume method (FVM). The discussion is briefly extended to two-dimensional modelling, as well as to computational fluid dynamics (CFD) approaches. Finite volume methods are of particular note, since they approximate the governing partial differential equations (PDEs) in a volume integral form, thus intrinsically conserving mass and momentum fluxes. Accuracy in transient modelling is particularly important in certain (typically more nuanced) applications, including fault (leakage and blockage) detection. The FVM, first advanced using Godunov’s scheme, is preferred in cases where wave celerity evolves over time (e.g., due to the release of air) or due to spatial changes (e.g., due to changes in wall thickness). Both numerical and experimental studies demonstrate that the first-order Godunov’s scheme compares favourably with the MOC in terms of accuracy and computational speed; with further advances in the FVM schemes, it progressively achieves faster and more accurate codes. The current range of numerical methods is discussed and illustrated, including highlighting both their limitations and their advantages.

show abstract

Section: Two-phase Flowmentioning

confidence: 99%

An Overview of the Numerical Approaches to Water Hammer Modelling: The Ongoing Quest for Practical and Accurate Numerical Approaches

Pal

Hanmaiahgari

Karney

2021

Water

View full text Add to dashboard Cite

show abstract

“…Thus, safety and economic enhancements encouraged designers to implement passive safety systems in those reactors already equipped with active safety devices. Such procedure has been Annals of Nuclear Energy 160 (2021) 108436 https://doi.org/10.1016/j.anucene.2021.108436 applied for the Advanced Power Reactor Plus (APR+) (Bae et al, 2012;Kang et al,2012) and the HPR1000 (Xing et al, 2016;Xiaofan et al, 2017). The integration of passive systems has successfully increased the safety of these reactors; however, the capability to mitigate the consequences of an ELAP scenario is still limited by the presence of active components.…”

Section: Introductionmentioning

confidence: 99%

Improvements of RELAP5/Mod3.3 heat transfer capabilities for simulation of in-pool passive power removal systems

Narcisi

Melchiorri

Giannetti

2021

Annals of Nuclear Energy

View full text Add to dashboard Cite

Despite system thermal-hydraulic codes were extensively validated for transient simulations of LWR, several activities highlighted limited capabilities of these tools to model heat transfer within in-pool passive power removal system. Discrepancies with experimental results were related to the underestimate of pool boiling and film condensation heat transfer coefficients. Thus, the DIAEE of "Sapienza" University of Rome developed a modified version of RELAP5/Mod3.3, able to handle fundamental heat exchange phenomena involved in passive in-pool safety systems. A primary validation procedure has been performed for separated and integral effects. Dealing with nucleate boiling, the Root Mean Squared Relative Error (RMSRE) of wall superheat has been reduced from 1.290 to 0.182. Concerning film condensation, wall temperature RMSRE has been reduced from 0.192 to 0.058. The integral effect assessment has involved an experimental test of the PERSEO facility. The qualitative comparison between experiments and calculations has highlighted significant improvements of the modified RELAP5/Mod3.3.

show abstract

“…The riser, connecting the outlet of the heater and the inlet of cooler, is adopted to improve the flow rate under two-phase conditions. Such NCSs are commonly adopted in the NPPs, such as Novel Modular Reactors (NMRs) (Singh et al, 2017), Passive Containment Cooling Systems (PCCSs) (Guo et al, 2017;Hou et al, 2017), and others (Park et al, 2007;Chen et al, 2013;Jiang et al, 2018). Sometimes the heat source is horizontally placed.…”

Section: Introductionmentioning

confidence: 99%

Effects of Direct Contact Condensation on Flow Characteristics of Natural Circulation System at Low Pressure

Sun

Zhang

et al. 2020

Front. Energy Res.

View full text Add to dashboard Cite

Direct contact condensation (DCC) as a complex thermal-hydraulic phenomenon has been the subject of a great deal of research under forced flow conditions. It is an interesting challenge to study the phenomenon in a natural circulation system (NCS). In this paper, the flow behaviors along with DCC phenomena were experimentally investigated by a visualization method in an NCS at low pressure. Moreover, the influence of initial parameters including heat flux, inlet temperature and resistance of the heated section on the NCS was analyzed in detail. The experimental results revealed that two types of DCC phenomena were found in the NCS. When Type I DCC occurs, the interface wave will be formed due to the hydraulic jump caused by the reverse flow of subcooled water. The interface wave easily contributes to the occurrence of Type II DCC due to the Kelvin-Helmholtz instability. In addition, the NCS tends to be more unstable with the increase in the heat flux or the inlet resistance. The influence of inlet temperature on the flow rate should comprehensively consider the changes of outlet parameters and subcooled degree of the steam and the subcooled water.

show abstract

Capability of RELAP5 code to simulate the thermal-hydraulic characteristics of open natural circulation

Cited by 41 publications

References 20 publications

An Overview of the Numerical Approaches to Water Hammer Modelling: The Ongoing Quest for Practical and Accurate Numerical Approaches

An Overview of the Numerical Approaches to Water Hammer Modelling: The Ongoing Quest for Practical and Accurate Numerical Approaches

Improvements of RELAP5/Mod3.3 heat transfer capabilities for simulation of in-pool passive power removal systems

Effects of Direct Contact Condensation on Flow Characteristics of Natural Circulation System at Low Pressure

Contact Info

Product

Resources

About