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NEA-0500 ALARM.

ALARM, Thermohydraulics of BWR with Jet Pumps During LOCA

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1. NAME OR DESIGNATION OF PROGRAM:  ALARM-B2.
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2. COMPUTERS
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Program name Package id Status Status date
ALARM-B1 NEA-0500/01 Tested 01-NOV-1977
ALARM-B2 NEA-0500/02 Tested 24-MAY-1985

Machines used:

Package ID Orig. computer Test computer
NEA-0500/01 IBM 370 series IBM 370 series
NEA-0500/02 FACOM M-380 IBM 3084Q
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3. NATURE OF PHYSICAL PROBLEM SOLVED

ALARM-B2 which is an improved version of ABARM-B1 is a computer program to analyze thermo-hydraulic phenomena of BWR during a blowdown period under a large-break loss-of-coolant accident condition with special emphasis on the heat transfer phenomena in the core region.
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4. METHOD OF SOLUTION

A so called volume-junction method is used to present fluid conservations. The primary system is divided into a number of special elements called "control-volumes". The system of partial differential equations describing fluid conservations for a  stream-tube are integrated over a number of control volumes. The resulting set of simultaneous differential equations that is based on the assumptions of one-dimensional, homogeneous and thermal- equilibrium flow is linearized and solved for a small time increment by a simple explicit numerical technique.
The one-dimensional heat conduction equations describing temperature profiles within solid material are written in finite difference forms which are linearized and solved by the Crank-Nicholson implicit method. In order to simulate the blowdown heat transfer phenomena, the code has correlation packages for heat  transfer coefficient and critical heat flux.
The heat generation in the core is given by a point reactor kinetics model with six groups of delayed neutrons and decay of eleven groups of fission products and actinides. The solution technique of the reactor kinetics is based on the Runge-Kutta method.
ALARM-B2 has the models to simulate various components incorporated in BWRs such as jet pumps, recirculation pumps, steam separators, valves, and so on. The discharge and injection systems are modeled by leak and fill systems, respectively.
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5. RESTRICTIONS ON THE COMPLEXITY OF THE PROBLEM

As this has been developed to simulate a blowdown thermo-hydraulic transient during a large break LOCA, users must pay attention when applying the code to any medium or small break LOCAs or to later phases of a large-break  LOCA.
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6. TYPICAL RUNNING TIME

The running time depends on the number of time steps and the complexity of the nodalization of the system to be analyzed. A rough estimate of CPU time requirement is about 2 ms/volume.step on FACOM M-380. As a BWR is usually modelled by 10  to 20 volumes with time step size of 0.1 to 1 milliseconds, the total CPU time for a transient of 50 seconds is 0.3 to 1 hours.
NEA-0500/02
NEA-DB executed the test cases included in the package  on IBM 3084Q. The following CPU times were found for the different steps:
         program                    seconds
         -------                    -------
         conversion program         0.68
         ALARM-B2: test case 1      4.3
                   test case 2      3.64
         MERGE                      0.49
         SPLPLOT-1                  0.71
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7. UNUSUAL FEATURES: UNUSUAL FEATURES OF THE PROGRAM
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8. RELATED AND AUXILIARY PROGRAMS

All input data are read in free format via a generalized subroutine REAG which converts BCD information to integer or floating numbers. The graphic information  is edited by the SPLPACK-1 program which has been developed for plotting the time dependent thermo-hydraulic variables.
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9. STATUS
Package ID Status date Status
NEA-0500/01 01-NOV-1977 Tested at NEADB
NEA-0500/02 24-MAY-1985 Tested at NEADB
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10. REFERENCES

- K. Muramatsu et Al.
  User's Manual for SPLPACK-1: A Program Package for Plotting and
  Editing of Experimental and Analytical Data of Various Transient
  Systems,
  JAERI-M 83-166 (1983).
- T. Shimizu
  Verification of LOCA/ECCS Analysis Code ALARM-B2 and THYDE-B1 by
  Comparison with RELAP4/MOD6/U4/J3 (in Japanese),
  JAERI-M 82-094 (1982).
- K. Asai , K. Tsuchiashi
  A Subroutine Reading Data in Free Format (in Japanese),
  JAERI-M 4458 (1971).
NEA-0500/01, included references:
- M. Akimoto
  "ALARM-B1, A Computer Program for Boiling Water Reactor Blowdown
  Analysis"
  JAERI-M 6968, March 1977.
NEA-0500/02, included references:
- Fumimasa Araya:
  ALARM-B2: A Computer Program for Analysis of Large Break Loca
  of BWR.  JAERI-M 9655  (Sept.1981; Rev. Sept.1984)
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11. MACHINE REQUIREMENTS:  The required storage is about 1600K bytes.
NEA-0500/02
Main storage requirements on IBM 3084Q are as follows:
             Conversion program:    128K bytes
             ALARM-B2:             1096K bytes
             MERGE:                 328K bytes
             SPLPLOT-1:             644K bytes
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12. PROGRAMMING LANGUAGE(S) USED
Package ID Computer language
NEA-0500/01 FORTRAN-IV
NEA-0500/02 FORTRAN-77
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13. OPERATING SYSTEM OR MONITOR UNDER WHICH PROGRAM IS EXECUTED

The program can be executed without specification of optimization using  the FORTRAN-77 compiler of the FACOM M-380 standard operating system.
NEA-0500/02
MVS-SP (IBM 3084Q).
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14. OTHER PROGRAMMING OR OPERATING INFORMATION OR RESTRICTIONS

ANY OTHER PROGRAMMING OR OPERATING INFORMATION OR RESTRICTIONS
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15. NAME AND ESTABLISHMENT OF AUTHOR

   F. Araya and M. Akimoto
   Department of Nuclear Safety Evaluation
   Japan Atomic Energy Research Institute
   Tokai-mura, Naka-gun, Ibaraki-ken, Japan
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16. MATERIAL AVAILABLE
NEA-0500/01
File name File description Records
NEA0500_01.001 LIBRARY DATA ( STEAM TABLE IN BCD FORM ) 2620
NEA0500_01.002 LIBRARY CONVERSION PROG. BCD TO BINARY (F4) 10
NEA0500_01.003 JCL OF CONVERSION PROGRAM 5
NEA0500_01.004 SOURCE PROGRAM - F4 - EBCDIC 8499
NEA0500_01.005 JCL 6
NEA0500_01.006 SAMPLE PROBLEM INPUT DATA 172
NEA0500_01.007 SAMPLE PROBLEM PRINTED OUTPUT 2032
NEA-0500/02
File name File description Records
NEA0500_02.001 INFORMATION FILE 224
NEA0500_02.002 ALARM-B2 SOURCE PROGRAM (CARD IMAGES) 21717
NEA0500_02.003 SPLPACK SOURCE PROGRAM (CARD IMAGES) 5779
NEA0500_02.004 SPLPLOT-1 SOURCE PROGRAM (CARD IMAGES) 5674
NEA0500_02.005 SPLUCL2 SOURCE PROGRAM (CARD IMAGES) 3968
NEA0500_02.006 CONVERSION PROGRAM FOR STEAM TABLES 38
NEA0500_02.007 MERGE SOURCE PROGRAM (CARD IMAGES) 713
NEA0500_02.008 SPLSUBR SOURCE PROGRAM (CARD IMAGES) 252
NEA0500_02.009 LOCF SOURCE (ASSEMBLER) 7
NEA0500_02.010 SETB99 ASSEMBLER ROUTINE 80
NEA0500_02.011 ADDITIONAL SUBROUTINES SOURCE 30
NEA0500_02.012 JCL 323
NEA0500_02.013 ALARM-B2 TEST CASE 1 INPUT DATA 253
NEA0500_02.014 ALARM-B2 TEST CASE 2 INPUT DATA 34
NEA0500_02.015 MERGE TEST CASE INPUT DATA 2
NEA0500_02.016 SPLPLOT-1 TEST CASE INPUT DATA 26
NEA0500_02.017 ALARM-B2 TEST CASE 1 PRINTED OUTPUT 3078
NEA0500_02.018 ALARM-B2 TEST CASE 2 PRINTED OUTPUT 2396
NEA0500_02.019 MERGE TEST CASE PRINTED OUTPUT 111
NEA0500_02.020 STEAM TABLE DATA LIBRARY (FORMATTED) 3867
NEA0500_02.021 SPLPLOT LABELING DATA 272
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17. CATEGORIES
  • G. Radiological Safety, Hazard and Accident Analysis

Keywords: BWR reactors, enthalpy, fluid flow, heat transfer, hydraulics, loss-of-coolant accident, pressure, pumps, reactor safety, thermodynamics.