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NESC0717 NAHAMMER

NAHAMMER, Pressure Transients in Na LMFBR Piping System, Linear Fluid Hammer Theory

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1. NAME OR DESIGNATION OF PROGRAM:  NAHAMMER
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2. COMPUTERS
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Program name Package id Status Status date
NAHAMMER NESC0717/01 Tested 01-APR-1979
NAHAMMER NESC0717/02 Tested 01-JUL-1978

Machines used:

Package ID Orig. computer Test computer
NESC0717/01 IBM 360 series IBM 360 series
NESC0717/02 CDC 7600 CDC 7600
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3. DESCRIPTION OF PROBLEM OR FUNCTION

NAHAMMER analyzes short-term pressure-pulse transients in a closed hydraulic system consisting of series or parallel piping, pipe junctions, diameter discontinuities, elbows, junctions of three to six branches, orifices, accoustic- impedance discontinuities, dummy junctions, dead ends, and free surfaces in surge tanks. The working fluid is assumed to be sodium without cavitation.
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4. METHOD OF SOLUTION

NAHAMMER considers a simplified one-dimensional linear inviscid set of governing equations. Classical fluid-hammer theory was linearized by neglecting the viscosity and recognizing that convective terms are negligible when the ratio of flow velocity to sonic speed is less than 0.01. Numericalsolutions are obtained by a simple superposition technique for tracing the waves traveling along each characteristic and for extending the solution from one constant time line to the next.
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5. RESTRICTIONS ON THE COMPLEXITY OF THE PROBLEM

The program currently provides for maxima of:
    50 legs
   120 nodes per leg
    50 junctions
    10 plenums (surge tanks)
The assumption of linearity restricts the maximum pressure at any propagating wave front in sodium to about 5800 psi. Calculations are limited to liquid sodium in the absence of cavitation. Friction- free fluid motion maintains its energy within any pipe section, but  conventional energy losses based on steady-state incompressible fluid flow are taken into account for elbows, diameter discontinuities, and orifice-like restrictions. To specify a working fluid other than sodium, the source coding must be changed.
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6. TYPICAL RUNNING TIME

Execution of the 48-leg sample problem requires about 16 CPU seconds on an IBM370/195 or about 4 CP seconds on a CDC7600.
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7. UNUSUAL FEATURES OF THE PROGRAM

In NAHAMMER the initial transient  is followed by a pressure pulse from a molten-fuel coolant interaction (MFCI) that produces a local pressure generation in the  fuel (heat-producing) region of the system. At the user's option, the pressure-time history during the MFCI either is calculated in subroutine DIFFUN according to an ANL rate-limited parametric model  or is input. The source region is a special region through which the waves are not allowed to travel.
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8. RELATED AND AUXILIARY PROGRAMS

WHAM6 (NESC Abstract 278), COMPARE  (NESC Abstract 702), HAMOC (NESC Abstract 710), NATRANSIENT (NESC Abstract 718), and NATRAN2 (NESC Abstract 719).
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9. STATUS
Package ID Status date Status
NESC0717/01 01-APR-1979 Tested at NEADB
NESC0717/02 01-JUL-1978 Tested at NEADB
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10. REFERENCES
NESC0717/01, included references:
W. L. Chen, D. H. Thompson, and Y. W. Shin:
A Computer Program for  Analysis of One-dimensional Pressure-pulse
Propagation in a Closed Fluid System, ANL-8059, May 1974
NESC0717/02, included references:
W. L. Chen, D. H. Thompson, and Y. W. Shin:
A Computer Program for  Analysis of One-dimensional Pressure-pulse
Propagation in a Closed Fluid System, ANL-8059, May 1974
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11. MACHINE REQUIREMENTS

362K bytes (IBM360,370), or 126,000 (octal) words (CDC6600,7600) of storage.
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12. PROGRAMMING LANGUAGE(S) USED
Package ID Computer language
NESC0717/01 FORTRAN-IV
NESC0717/02 FORTRAN-IV
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13. OPERATING SYSTEM UNDER WHICH PROGRAM IS EXECUTED

      OS/360,370
(IBM360,370), SCOPE 3.4.3 (CDC6600), or SCOPE 2.1.2 (CDC7600).
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14. OTHER PROGRAMMING OR OPERATING INFORMATION OR RESTRICTIONS:
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15. NAME AND ESTABLISHMENT OF AUTHORS

   360           W. L. Chen and D. H. Thompson
                 Reactor Analysis and Safety Division
                 Y. W. Shin
                 Components Technology Division
                 Argonne National Laboratory
                 9700 South Cass Avenue
                 Argonne, Illinois  60439
   7600          H. S. Edwards
                 National Energy Software Center
                 Argonne National Laboratory
                 9700 South Cass Avenue
                 Argonne, Illinois  60439
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16. MATERIAL AVAILABLE
NESC0717/01
File name File description Records
NESC0717_01.001 SOURCE PROGRAM (F4,EBCDIC) 1013
NESC0717_01.002 SAMPLE PROBLEM INPUT DATA 75
NESC0717_01.003 SAMPLE PROBLEM PRINTED OUTPUT 1691
NESC0717/02
File name File description Records
NESC0717_02.001 INFORMATION 3
NESC0717_02.002 SOURCE PROGRAM (F4) 904
NESC0717_02.003 SAMPLE PROBLEM INPUT DATA 75
NESC0717_02.004 SAMPLE PROBLEM PRINTED OUTPUT 1691
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17. CATEGORIES
  • G. Radiological Safety, Hazard and Accident Analysis

Keywords: LMFBR reactors, liquid metals, one-dimensional, pressure, reactor safety, transients.