**RSICC CODE PACKAGE PSR-410**

**1. NAME AND TITLE**

COMPARE-MOD1A: Transient Flow W/Sinks & Doors.

**2. CONTRIBUTORS**

Los Alamos National Laboratory, Los Alamos, New Mexico through the Energy Science and Technology Software Center, Oak Ridge, Tennessee and the NEA Data Bank, Gif-sur-Yvette, France.

**3. CODING LANGUAGE AND COMPUTER**

FORTRAN IV; CDC7600 (P00410C760000).

FORTRAN IV; IBM3033 (P00410I303300).

**4. NATURE OF PROBLEM SOLVED**

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 subcompartment analysis of nuclear power plants, including those with ice condensers.

**5. METHOD OF SOLUTION**

Volume thermodynamics and junction flows are determined independently in a quasi-static explicit manner. Mass and energy inflow or outflow accounting for each volume is done first for each time increment, assuming vent flows are constant. Thermodynamic 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.

**6. RESTRICTIONS OR LIMITATIONS**

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, and 100 junctions with detailed loss coefficient information.

**7. 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.

**8. COMPUTER HARDWARE REQUIREMENTS**

157,000 (octal) words on a CDC7600, 153,000 (octal) words on a CDC CYBER175.

**9. COMPUTER SOFTWARE REQUIREMENTS**

LASL FTN operating system (similar to CDC SCOPE) (CDC7600); NOS2.2 (CDC CYBER175).

**10. REFERENCES**

**a) Included in documentation:**

R. G. Gido, G. J. E. Willcutt, Jr., J. L. Lunsford, J. S. Gilbert, "COMPARE-MOD 1 Code Addendum," NUREG/CR-1185, Addendum 1; LA-7199-MS, Addendum (June 1980).

"Compare-Mod 1: A Code for the Transient Analysis of Volumes with Heat Sinks, Flowing Vents, and Doors," LA-7199-MS (March 1978).

M. Birgersson, "COMPARE-MOD1A, NESC No. 776.3033B, COMPARE-MOD1A Tape Description and Implementation Information," NESC Note 86-05 (October 8, 1984).

M. Birgersson, "COMPARE-MOD1A, NESC No. 776.7600D, COMPARE-MOD1A Tape Description and Implementation Information," NESC Note 86-07 (October 8, 1984).

**b) Background information:**

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).

**11. CONTENTS OF CODE PACKAGE**

Included with the package are the referenced documents in (10.a) and one DS/HD diskette containing a self-extracting compressed DOS file. Executables are not included with the package. A source deck, sample problem and plotting routine are included on the diskette.

**12. DATE OF ABSTRACT**

October 1999.

** KEYWORDS:** FLUID DYNAMICS; LOCA