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NESC0710 HAMOC

HAMOC, Pressure Transients in Reactor Vessel Piping System after Accidents

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1. NAME OR DESIGNATION OF PROGRAM:  HAMOC
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2. COMPUTERS
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Program name Package id Status Status date
HAMOC NESC0710/01 Tested 01-DEC-1978

Machines used:

Package ID Orig. computer Test computer
NESC0710/01 CDC 7600 CDC 7600
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3. DESCRIPTION OF PROBLEM OR FUNCTION

HAMOC determines the pressure
transients in  piping systems attached  to a reactor  vessel which
has been  perturbed, by  a hypothetical  core disruptive  accident
(HCDA) for  example.  The  continuity and  momentum equations  are
solved.  The  energy equation  is not  programmed, but  simplified
column separation logic is included to treat vapor pressures below
saturation.   This simplified  approach has  been checked  against
experimental data.  HAMOC was written specifically for problems in
which forcing pressures are known as a function of time at certain
end boundary conditions, rather than as a general purpose code for
the solution of pump coastdown or valve closing problems.
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4. METHOD OF SOLUTION

The differential equations  of continuity and
momentum are solved by the method of characteristics.  When column
separation  occurs,  special  internal   boundary  conditions  are
temporarily established  which fix the  pressure at  the saturated
vapor  pressure  during  the existence  of  the  cavity.   Special
equations give the pressure rise when the cavity collapses.
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5. RESTRICTIONS ON THE COMPLEXITY OF THE PROBLEM

The        program
currently provides for maxima of:
     56 legs
     50 nodes per leg
     15 three-way junctions
     50 plots
   1000 points per plot
      1 line per plot
The fluid properties are those for sodium, and the pipe properties
are those  for Type 304  stainless steel.  The  above restrictions
should not be  difficult to alter; the  following restrictions are
more stringent.   There may be  1 or  2 pipe ends  with prescribed
pressure-time  history.    All  pumps   have  the   same  set   of
characteristics.  Fluid  temperatures must be constant  with time,
must be the same for all points within a leg, and must be the same
for all connecting legs  at a pump, at a tee,  or at a Y-junction.
The minimum leg length must not be smaller than
   (time-step)*(pressure-pulse-speed + fluid-velocity).
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6. TYPICAL RUNNING TIME

The  45-leg sample  problem requires  about
110 seconds  (CYBER74-18) or 21  seconds (CDC7600)  execution time
for a run of 0.1 seconds  real time.  Typically, execution time on
the CYBER74-18  is about  0.00057 second  per mesh-point  per time
plane.  Running  times can be  reduced significantly,  with little
loss of accuracy, by using a constant friction factor.
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7. UNUSUAL FEATURES OF THE PROGRAM:
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8. RELATED AND AUXILIARY PROGRAMS:  WHAM6 (NESC Abstract 278).
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9. STATUS
Package ID Status date Status
NESC0710/01 01-DEC-1978 Tested at NEADB
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10. REFERENCES

H. G. Johnson,  HAMOC - A Computer  Program for Fluid
Hammer Analysis, HEDL-TME 75-119, December 1975.
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11. MACHINE REQUIREMENTS

A 131K machine is  required with dummy plot
routines; HAMOC requires 101,000 (octal) words of storage.  A tape
is used to store data for offline plotting.
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12. PROGRAMMING LANGUAGE(S) USED
Package ID Computer language
NESC0710/01 FORTRAN-IV
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13. OPERATING SYSTEM UNDER WHICH PROGRAM IS EXECUTED

   SCOPE   3.4.2
(CYBER74-18), SCOPE 3.4.4 (CDC6600), SCOPE 2.1.3 (CDC7600).
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14. OTHER PROGRAMMING OR OPERATING INFORMATION OR RESTRICTIONS

It is
assumed that  the operating  system will zero  the memory  at load
time.  Plotting  calls are to  standard CalComp  subroutines.  The
source  file contains  COMDECKs.  It  should be  processed by  the
UPDATE utility before compilation.
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15. NAME AND ESTABLISHMENT OF AUTHOR

                 H. G. Johnson
                 Hanford Engineering Development Laboratory
                 Westinghouse Hanford Company
                 P. O. Box 1970
                 Richland, Washington  99352
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16. MATERIAL AVAILABLE
NESC0710/01
File name File description Records
NESC0710_01.001 INFORMATION 2
NESC0710_01.002 SOURCE PROGRAM (F4) 2189
NESC0710_01.003 JCL 5
NESC0710_01.004 SAMPLE PROBLEM INPUT DATA 70
NESC0710_01.005 SAMPLE PROBLEM PRINTED OUTPUT 5583
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17. CATEGORIES
  • G. Radiological Safety, Hazard and Accident Analysis

Keywords: liquid metals, pressure, reactor safety, transients.