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RSICC CODE PACKAGE PSR-488

1. NAME AND TITLE

TRAC-BD1: Code System for Best-Estimate Analysis of LOCA in BWR.



2. CONTRIBUTORS

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



3. CODING LANGUAGE AND COMPUTER

CDC Fortran Extended Version 4 and COMPASS; CDC CYBER176 (P00488C017600).



4. NATURE OF PROBLEM SOLVED

TRAC-BD1 performs best estimate analyses of loss-of-coolant accidents (LOCA) and other transients in boiling water reactors (BWRs). The program provides LOCA analysis capability for BWRs and for many BWR-related thermal-hydraulic experimental facilities. The program features a three-dimensional treatment of the BWR pressure vessel, a detailed model of a BWR fuel bundle including multi-rod, multi-bundle, radiation heat transfer, and leakage path modeling capability; flow-regime-dependent constitutive equation treatment; reflood tracking capability both for falling films and bottom flood quench fronts; and consistent treatment of the entire accident sequence. Dump/restart capabilities are also provided.



5. METHOD OF SOLUTION

The system of partial differential equations describing the two-phase flow and heat transfer is solved by use of finite difference techniques. The heat transfer equations are treated as one-dimensional using a semi-implicit differencing technique. The finite difference equations for hydrodynamic phenomena form a system of coupled, nonlinear equations solved by a Newton-Raphson iteration procedure



6. RESTRICTIONS OR LIMITATIONS

All storage arrays in the program are dynamically allocated; the only limit on the size of a problem is the amount of memory available. The number of reactor components in the problem and the manner in which they are coupled is arbitrary



7. TYPICAL RUNNING TIME

Running time is highly problem-dependent and is a function of the total number of mesh cells and the maximum allowable time-step size. The longest running sample problem requires about 2.5 minutes CPU on a CDC6600.



8. COMPUTER HARDWARE REQUIREMENTS

TRAC-BD1 ran on a CDC CYBER176 computer with 65K words of small core memory (SCM) and 220K words of large core memory (LCM).



9. COMPUTER SOFTWARE REQUIREMENTS

CDC CYBER176 ran under the NOS/BE 1.4 operating system and OVERLAY loader. COMPASS and Fortran compilers are required. Non-CDC use will require significant conversion effort due primarily to the TRAC-BD1 use of CDC overlay structure and Large Core Memory (LCM) storage. The package was not tested, and no changes were made when it was transferred to RSICC and released in July 2001.



10. REFERENCES

a) included in documentation:

J.W. Spore, M.W. Giles, G.L. Singer and R.W. Shumway, "TRAC-BD1: An Advanced Best Estimate Computer Program for Boiling Water Reactor Loss-of-Coolant Accident Analysis," NUREG/CR-2178, Volume 2 (October 1981).

L. Reed, TRAC-BD1, NESC No. 1031.C176B, "TRAC-BD1 Tape Description and Implementation Information," National Energy Software Center Note 84-30 (April 30, 1984).



b) background references:

J.W. Spore, M.W. Giles, G.L. Singer and R.W. Shumway, "TRAC-BD1: An Advanced Best Estimate Computer Program for Boiling Water Reactor Loss-of-Coolant Accident Analysis," NUREG/CR-2178, Volumes 1, 3, and 4 (October 1981).

M.M. Aburomia, "BWR Refill-Reflood Program,TRAC-BWR Component Development," NUREG/CR-2135 (EPRI-NP-1583/GEAP-24941) (December 1981).

C. M. Kullberg, "Overview of TRAC-BD1 (Version 12) Assessment Studies," NUREG/CR-4196 (EGG-2382) (April 1985).



11. CONTENTS OF CODE PACKAGE

Included are the referenced documents in 10.a and one DS/HD diskette with a self-extracting DOS file that contains the source files, test case input and output and control statements.



12. DATE OF ABSTRACT

July 2001.



KEYWORDS: LOCA; LWR; REACTOR SAFETY; THERMAL HYDRAULICS