NESC0776 COMPARE-MOD1A.

1. NAME OR DESIGNATION OF PROGRAM:  COMPARE-MOD1A

3. DESCRIPTION OF PROBLEM OR FUNCTION

COMPARE-MOD1A performs transient analysis of the thermodynamic conditions in zero velocity  or stagnant volumes connected by flowing junctions with provision for mass and energy addition. Volume thermodynamics and junction flows are for homogeneous mixtures of: steam, two-phase water to its triple point, any three perfect gases, or combinations of the above. Vent flow can be based on the Moody equation, compressible polytropic orifice flow, and an incompressible subelement inertial relationship. Variable area doors and heat sinks can be modeled. Capabilities are incorporated to provide for accounting of loss coefficient detail, calculation of forces and moments, and plotting  of results. The program was written to perform transient sub- compartment analysis of nuclear power plants, including those with ice condensers.

4. METHOD OF SOLUTION

Volume thermodynamics and junction flows are determined independently in a quasi-static explicit manner. Mass and energy inflow of outflow accounting for each volume is done first for each time increment, assuming vent flows are constant. Thermo- dynamic equilibrium is assumed and state points determined. The resulting thermodynamic conditions are assumed constant and used to  calculate the new vent flows between volumes for the next time interval.

5. RESTRICTIONS ON THE COMPLEXITY OF THE PROBLEM

Maxima of

      100 volumes
      200 junctions
        5 mass and energy addition tables (blowdown sets)
       10 variable area doors
      500 heat sink nodal points
      100 force-moment surfaces
      100 junctions with detailed loss coefficient information
   10,000 points plotted
        5 curves per plot
Water temperature is restricted to the range of 273.16 to 620 degrees K (32.018 to 656 degrees F). Quality minimum is about 0.001. Time increment selection is important because too large a value may  result in volume mass being less than or equal to zero. Options are  available to guide the user in time increment selection.

6. TYPICAL RUNNING TIME

A two-volume, one-flow junction problem requires 0.002 second per time-step on the CDC7600. The sample problem requires 0.002 CP second per time-step on a CDC CYBER175. The sample problem runs in 2 seconds on an IBM3033.

NEA-DB executed the test case included in this package  on an IBM 3084Q computer in 0.83 seconds of CPU time.

7. UNUSUAL FEATURES OF THE PROGRAM

Ideal-like gas polytropic equations are used to calculate orifice flow, including losses. Two-phase water with air flow is calculated. Inertial effects and compressibility in the one-dimensional momemtum equation are taken into account.

8. RELATED AND AUXILIARY PROGRAMS

COMPARE-MOD1A is an extension of COMPARE-MOD1, which was a later version of COMPARE (NESC Abstract 702), containing additional features. COMPARE-MOD1A uses an auxiliary program, GENPLT, to plot key parameters such as pressures, forces, and moments.

10. REFERENCES

- R.G. Gido, R.G. Lawton, C.I. Grimes, and J.A. Kudrick,
  COMPARE: A Computer Program for the Transient Calculation of a System of Volumes Connected by Flowing Vents,
  LA-NUREG-6488-MS, September 1976.

- R.G. Gido, J.S. Gilbert, R.G. Lawton and Walton L. Jensen:
  COMPARE-MOD1: A Code for Transient Analysis of Volumes with Heat
  Sinks, Flowing Vents and Doors. LA-7199-MS  (March 1978).
- R.G. Gido, G.J.E. Willcutt Jr., J.L. Lunsford and J.S. Gilbert:
  COMPARE-MOD1 Code Addendum.
  NUREG/CR-1185, Addendum 1  LA-7199-MS, Addendum (June 1980)
- COMPARE-MOD1 Code Addendum (NUREG/CR-1185, Addendum 1 (LA-7199-MS,
  Addendum))  (September 25, 1980).
- M. Birgersson:
  COMPARE-MOD1A Tape Description and Implementation Information.
  NESC Note 85-05  (October 8, 1984)

11. MACHINE REQUIREMENTS

157,000 (octal) words on a CDC7600, 153,000 (octal) words on a CDC CYBER175, 712K bytes on an IBM3033.

To run the test case on IBM 3084Q, 730K bytes of main storage were required.

13. OPERATING SYSTEM UNDER WHICH PROGRAM IS EXECUTED

LASL, FTN operating system (similar to CDC SCOPE) (CDC7600), NOS2.2 (CDC CYBER175), MVS (IBM3033).

The test case ran under MVS/SP (IBM 3084Q).

14. OTHER PROGRAMMING OR OPERATING INFORMATION OR RESTRICTIONS

NESC added a dummy TIMING routine to the CDC version for completeness. TIMING is a Los Alamos computing environment routine which should be replaced with an alternative suitable for the environment in which the program is implemented. For plotting, the auxiliary GENPLT program makes use of the Integrated Software Systems Corporation (ISSCO) proprietary graphics software product, DISSPLA.

15. NAME AND ESTABLISHMENT OF AUTHOR

  CDC7600      R.G. Gido, G.J.E. Willcutt, Jr.,
               J.L. Lunsford, and J.S. Gilbert
               Los Alamos National Laboratory
               P.O. Box 1663
               Los Alamos, New Mexico 87545

  3033         K.J. Conrade
               Gibbs & Hill, Inc.
               393 Seventh Avenue
               New York, New York 10001

  3033 GENPLT  M. Birgersson and L. Eyberger
               National Energy Software Center
               Argonne National Laboratory
               9700 South Cass Avenue
               Argonne, Illinois 60439

File name	File description	Records
NESC0776_05.001	information file	66
NESC0776_05.002	job control instructions	159
NESC0776_05.003	COMPARE-MOD1A source program	5990
NESC0776_05.004	COMPARE-MOD1A test case input data	120
NESC0776_05.005	GENPLT auxiliary plotting program	444
NESC0776_05.006	COMPARE-MOD1A test case printed output	1338