Thermal-Hydraulics

  RELAP5

EDA, Inc

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RELAP5/MOD3 is a "best estimate" system code suitable for the analysis of all transients and postulated accidents in Light Water Reactor (LWR) systems, including both large- and  small-break loss-of-coolant accidents (LOCAs) as well as the full range of operational transients.  The one dimensional RELAP5/MOD3 code is based on a non-homogeneous and non-equilibrium model for the two-phase system that is solved by a fast,  partially implicit numerical scheme to permit economical calculation of system transients.   As a part of the severe accident core meltdown code SCDAP/RELAP5, RELAP5/MOD3  describes the thermal hydraulic aspects of both LWR systems and of the degrading core. RELAP5 and the coupled version SCDAP/RELAP5 are being developed at INEEL.  

In addition, RELAP5 can be used to solve many plant thermal-hydraulic problems.  Modeling of single and two-phase systems can be accomplished using many types of valves, heat exchangers and pumps.  Using the best estimate (BE) code, RELAP5, for probabilistic safety analysis (PSA) has be performed with much success.

The code includes many generic models allowing to simulate general thermo hydraulic systems. The models include pumps, valves, pipes, heat releasing or absorbing structures, reactor point kinetics, electric heaters, jet pumps, turbines, separators, accumulators, and control system logic elements.  RELAP5 represents the aggregate accumulation of experience in modeling reactor core behavior during accidents, two-phase flow processes, and LWR systems. The code development has benefited from extensive application and validation against a lot of experimental programs.

 

  • ACGRACE  Analysis Code, GRaphing, Advanced Computation and Exploration of data

 

 

 

The SCDAP/RELAP5  code package is composed of:

  • The Severe Core Damage Analysis Package (SCDAP) originally designed at INEL to simulated the core behavior under simplified thermal hydraulic conditions (water & steam, single pipe). It has been verified against several in-pile and out-of pile test ([PBF], CORA).
  • The RELAP5 thermal hydraulic code used for analyses of the reactor coolant systems under normal operation as well as under design basis accidents (i.e. LOCA). The code includes also a point-kinetics neutronic model to model reactivity effects of the fluid composition and density.
This coupled code package is used for detailed accident analyses including severe accidents for existing as well as future power plants. 
For another post-processing the tool XMGR5 is available on request. The XMGR5  is a tool for 2-D graphics including a versatile interface to various data types. (For more information see  [XMGR5] )
Note: Parts taken from IRS LWR Safety Research and from  FZK/IRS LWR Safety Research.

If you would like to know more about RELAP5, please contact RelapAdministrator@thcentral.com  . 

Other Useful Links:

  • A COMPARISON OF THE PARET/ANL AND RELAP5/MOD3 CODES
    FOR THE ANALYSIS OF IAEA BENCHMARK TRANSIENTS
     
    The PARET/ANL and RELAP5/MOD3 codes are used to analyze the series of benchmark transients specified for the IAEA Research Reactor Core Conversion Guidebook (IAEA-TECDOC-643 , Vol. 3). The computed results for these loss-of-flow and reactivity insertion transients with scram are in excellent agreement and agree well with the earlier results reported the guidebook. Attempts to also compare RELAP5/MOD3 with the SPERT series of experiments are in progress. Download PDF of paper.

  • Program of RELAP5 Users Group  Program of the International RELAP5 Users Group (IRUG); 19 and 20 October 2000

 

 

 

  • Assessment of the RELAP5-3D    RELAP5-3D is the latest version of the RELAP series of computer programs that are used for the thermal-hydraulic safety analysis of water-moderated nuclear reactors. In this version of the code, a three-dimensional simulation of thermal-hydraulic and neutronic phenomena occurring in a reactor can be simulated.    Recently, a number of papers have appeared in the literature in which attention has been devoted to the RELAP5 code's predictions of low-pressure flow boiling experiments. These studies have been motivated by the need to use the RELAP5 code for the thermal-hydraulic safety analysis of research reactors and advanced reactors with passive safety features.  The primary objective of the present study is to study some of the experimental data on low-pressure subcooled flow boiling available in the literature, and to utilize them as validation cases, for thermal-hydraulic computer codes. Moreover, this study was also conducted to investigate the suitability of the SRL model for low-pressure subcooled flow boiling.

 

 

  • RSICC CODE PACKAGE PSR-423 - RELAP5
    RELAP5 was developed to describe the behavior of a light water reactor (LWR) subjected to postulated transients such as loss of coolant from large or small pipe breaks, pump failures, etc. RELAP5 calculates fluid conditions such as velocities, pressures, densities, qualities, temperatures; thermal conditions such as surface temperatures, temperature distributions, heat fluxes; pump conditions; trip conditions; reactor power and reactivity from point reactor kinetics; and control system variables. In addition to reactor applications, the program can be applied to transient analysis of other thermal-hydraulic systems with water as the fluid. This package contains RELAP5/MOD1/029 for CDC computers and RELAP5/MOD1/025 for VAX or IBM mainframe computers.
   

 

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