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NEA-1686 ENTREE 1.4.0.

ENTREE 1.4.0, BWR Core Simulation System for Space and Time Dependent Coupled Phenomena

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1. NAME OR DESIGNATION OF PROGRAM:  ENTREE 1.4.0.
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2. COMPUTERS
To submit a request, click below on the link of the version you wish to order. Only liaison officers are authorised to submit online requests. Rules for requesters are available here.
Program name Package id Status Status date
ENTREE 1.4.0 NEA-1686/01 Tested 01-SEP-2011

Machines used:

Package ID Orig. computer Test computer
NEA-1686/01 Linux-based PC,SUN,DEC ALPHA W.S. Linux-based PC
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3. DESCRIPTION OF PROGRAM OR FUNCTION

ENTREE is a plant simulation code system that can be applicable to operational transients, coupled neturonic-thermal hydraulic instability and reactivity insertion accidents. The main objectives of ENTREE are development, verification and application of the three-dimensional plant simulation system TRAC/BF1-ENTREE-ACCORD-N for boiling water reactors (BWRs). The coupling phenomena considered in the BWR design field were reviewed in terms of their phenomenological natures. Basic specifications of existing three-dimensional plant simulation codes were compared with regard to modeling of neutron kinetic, two-phase flow dynamic and fuel heat conduction.
ENTREE is a three-dimensional neutron kinetic code based on the modern nodal methods. The assembly discontinuity factor (ADF) and the pin power reconstruction capabilities are also implemented for transient calculations, and they permit evaluation of detailed local pin power transition. The fully implicit scheme is implemented to deal with not only slow but also fast power transients based on the same formulations.
The modal analysis code ACCORD-N solves the two or three-dimensional higher neutron flux modes based on the two energy group diffusion equation. The higher neutron flux modes supply basic information for understanding space-dependent neutron kinetics. Specifically, they are fully utilized in regional instability evaluation as the shape function of external disturbance used for evaluating core stability. They are also useful in quantifying inter-modal interaction.
  
This ENTREE package includes the ENTREE and ACCORD-N codes; it does not include TRAC/BF1, which is proprietary code. TRAC/BF1 is a state-of-the-art plant simulation code based on the two-fluid model. Non-equilibrium two-phase fluid dynamics permits one to analyze not only slow, moderate transients but also fast transients without switching the basic governing equations.
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4. METHODS

The high-speed and accurate three-dimensional neutron kinetic code ENTREE was developed based on polynomial and semi-analytical nonlinear iterative methods (PNLM and SANLM) including the discontinuity factor. Several numerical techniques were introduced to enhance transient calculation efficiency.
The CCCMA (Correction Coupling Coefficient Modal Analysis) has been proposed to improve spatial resolution of neutron flux modal analysis. The improvement was achieved by including the NLM (Nonlinear Iterative Method)-correction coupling coefficient. The new complex code system, ENTREE-ACCORD-N was introduced based on this methodology.
Adequacy and performance of the coupling system TRAC/BF1-ENTREE was demonstrated based on the BWR cold water injection transient proposed by NEA/NSC, the Peach Bottom 2 turbine trip test and the BWR-5 one-pump trip test.
The applicability of TRAC/BF1-ENTREE-ACCORD-N to the regional instability was extensively discussed. Fundamental aspects of regional instability were studied first based on the extended frequency-domain model that is suitable for systematic parameter studies. Fidelity of TRAC/BF1 was studied next based on the FRIGG-4 loop test with regard to the thermal hydraulic mechanism (density-wave oscillation) underlying in the regional instability. Following this purely thermal hydraulic study, methodology of TRAC/BF1-ENTREE has been established for regional instability evaluation from the viewpoint of the reactivity feedback mechanism. Furthermore, core stability was estimated under the pseudo numerical noise that simulates the actual in-core random noise disturbance. This noise analysis technique gave realistic and reliable decay ratios.
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5. RESTRICTIONS ON THE COMPLEXITY OF THE PROBLEM
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6. TYPICAL RUNNING TIME

Depends on the size of the problem and operating system (the supplied sample problems range from small steady-state cases to huge transient cases).
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7. UNUSUAL FEATURES
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8. RELATED OR AUXILIARY PROGRAMS
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9. STATUS
Package ID Status date Status
NEA-1686/01 01-SEP-2011 Tested at NEADB
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10. REFERENCES
NEA-1686/01, included references:
- A. Hotta, "ENTREE Version 1.4.0 User''s Manual," TEPCO Systems Corp., Tokyo
Institute of Technology (May 2002)
- A. Hotta, "Theory and Verification Manual - Development and Verification of a
BWR Core Simulation System for Space and Time Dependent Coupled Phenomena,"
Thesis for Tokyo Institute of Technology
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11. HARDWARE REQUIREMENTS

ENTREE runs on Intel PC under Linux and on Compaq Alpha and Sun workstations.
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12. PROGRAMMING LANGUAGE(S) USED
Package ID Computer language
NEA-1686/01 FORTRAN
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13. SOFTWARE REQUIREMENTS

These codes run under Linux on Intel personal computers, on Compaq Alpha-TRUE64 V4.0F UNIX workstations, and on Sun under Sun OS5.5.1. Fortran 77 and C compilers are required. The package contains post-processing codes for PC Windows environment. GNUPLOT 3.8 and PVM version 3.4 software is included.
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14. OTHER PROGRAMMING OR OPERATING INFORMATION OR RESTRICTIONS
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15. NAME AND ESTABLISHMENT OF AUTHORS

Dr. Akitoshi HOTTA
In-Core Management Systems Dept.
TEPCO System Corporation
Shibusawa City Place Bldg.
2-37-28, Eidai,
Koto-ku, Tokyo
  
Tokyo Institute of Technology
2-12-1 O-okayama
Meguro-ku
Tokyo 152-8550
Japan
  
The format of the multi-table binary cross sections (TABLES Cross Section) is the proprietary information of Studsvik of America. The relevant parts as listed in the attached document "Proprietary" were excluded from ENTREE, users manual, sample problems and tools. These concealed parts will be supplied to users who can prove by written evidence to be the official users of CASMO/SIMULATE. Please contact Akitoshi Hotta: hotta-akitoshi@tepsys.co.jp
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16. MATERIAL AVAILABLE
NEA-1686/01
Input Description
File Description
Coupling Method
Memory Allocation
Subroutine Tree Chart
Subroutine Description
Graphics
Tools Description
Tutorial
ACCORD-N
Theoretical Manual
Users Manual
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17. CATEGORIES
  • F. Space - Time Kinetics, Coupled Neutronics - Hydrodynamics - Thermodynamics

Keywords: BWR reactors, coupled neutronics thermal hydraulics, reactor safety, thermal hydraulics, transients.