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RSICC CODE PACKAGE PSR-416



1. NAME AND TITLE

RELAP4/MOD7/101: A Best Estimate Computer Program to Calculate Thermal and Hydraulic Phenomena in a Nuclear Reactor or Related System.



AUXILIARY

PRELOAD Reduces the amount of storage required to run RELAP4.

PLOTR4M Generates microfilm or Calcomp plots.



2. CONTRIBUTORS

EG & G Idaho, Inc., Idaho Falls, Idaho through the Energy Science and Technology Software Center, Oak Ridge, Tennessee.



3. CODING LANGUAGE AND COMPUTER

FORTRAN IV (95%) and COMPASS (5%); CDC CYBER176 or CDC 7600 (P00416C760000).



4. NATURE OF PROBLEM SOLVED

RELAP4/MOD7/101 performs best estimate analyses of nuclear reactors or related systems undergoing a transient. Transient thermal-hydraulic, two-phase phenomena are calculated from formulations of one-dimensional, homogeneous, equilibrium conservation equations for water mass, momentum, and energy. Heat structures are modeled using a transient one-dimensional heat conduction solution that is coupled to the fluid through heat transfer relations. Various explicit models are used to calculate nonhomogeneous, nonequilibrium behavior including a phase separation model, a vertical slip model, and a nonequilibrium model. Other models are used to represent critical flow, reactor kinetics, pressurized water reactor reflood behavior, nuclear fuel rod swelling and blockage, and components such as pumps, valves, and accumulators.



5. METHOD OF SOLUTION

The RELAP4 user must define the geometric features of the system to be analyzed as well as an appropriate set of initial conditions. RELAP4 then solves an integral form of the fluid conservation and state equations applied to each user-defined control volume.



6. RESTRICTIONS OR LIMITATIONS

Maxima of 9 minor edit variables, 20 time-step cards, 20 trip control cards, 100 junctions (flow paths) between volumes, 5 bubble-parameter sets, 5 time-dependent volume descriptions on cards, 12 pumps, 99 control volumes, 10 check valve types, 5 normalized leak-area-versus-time curves, 20 fill system curves, 50 heat slabs, 20 heat slab geometries, 7 heat slab materials, 50 core sections and 99 data sets for heat exchangers without conduction.



7. TYPICAL RUNNING TIME

For a PWR modeled with 30 to 40 fluid volumes, running time through reflood may range from 30 to 90 minutes or more on the CDC7600. The four sample problems require a total of 55 CP seconds to run on a CDC7600.



8. COMPUTER HARDWARE REQUIREMENTS

160,000 (octal) words of SCM and 200,000 (octal) words of LCM (CDC7600), 3 tape drives, and a plotter.



9. COMPUTER SOFTWARE REQUIREMENTS

NOS/BE (CDC CYBER176); SCOPE 2.1.5 (CDC7600).



10. REFERENCES

a) Included in Package:

S. R. Behling, et al., "ELAP4/MOD7 - A Best Estimate Computer Program to Calculate Thermal and Hydraulic Phenomena in a Nuclear Reactor or Related System," NUREG/CR-1998 (EGG-2089) (August 1981).

S. R. Behling, Ming T. Hsu, C. A. Dobbe, and S. R. Fischer, "RELAP4/MOD7 - A Best Estimate Computer Program to Calculate Thermal and Hydraulic Phenomena in a Nuclear Reactor or Related System," Supplement 1, NUREG/CR-1998 (EGG- 2089), Supplement 1 (November 1981).

M. Birgersson, "RELAP4/MOD7/101, NESC No. 369.C176, Description of RELAP4/MOD7/101 Tape for Use on CDC Cyber176 and CDC-Compatible Systems and Implementation Information," National Energy Software Center Note 83-04 (August 24, 1982).

M. Birgersson, "RELAP4/MOD7/101, NESC No. 369.C176B, Description of RELAP4/MOD7/101 Tape for Reading on Non-CDC Systems and Implementation Information," National Energy Software Center Note 83-05 (August 24, 1982).



b) Background Information:

G.D. Brown, C.H. Bush, and R.A. Berman, "The Integrated Graphics System for the SC4060: I. User's Manual," Memorandum RM-5660-PR (December 1968).



11. CONTENTS OF CODE PACKAGE

Included are the reference documents in (10.a), source and sample problem input and output in a tar file on one CD ROM.



12. DATE OF ABSTRACT

May 1999.



KEYWORDS: LOCA; NUCLEAR SAFETY; THERMAL HYDRAULICS; HEAT TRANSFER