NESC0836 TRAC-PF1.

1. NAME OR DESIGNATION OF PROGRAM:  TRAC-PF1.

3. DESCRIPTION OF PROBLEM OR FUNCTION

TRAC-PF1 performs best-estimate analyses of loss-of-coolant accidents and other transients in pressurized light water reactors. The program can also be used to model a wide range of thermal-hydraulic experiments in reduced-scale facilities. Models employed include reflood, multi-dimensional two-  phase flow, nonequilibrium thermodynamics, generalized heat transfer, and reactor kinetics. Automatic steady-state and dump/ restart capabilities are provided. The changes reported in TRACNEWS  issues through Number 7 are incorporated in this release.

4. METHOD OF SOLUTION

The partial differential equations describing the two-phase flow and heat transfer are solved by finite differences. The heat-transfer equations are treated using a semi- implicit differencing technique. The fluid-dynamics equations in the one-dimensional components use a multistep procedure that allows the material Courant condition to be violated. The three-dimensional vessel option uses semi-implicit differencing. The finite-difference equations for hydrodynamic phenomena form a system of coupled, nonlinear equations that are solved by a Newton-Raphson iteration procedure.

5. RESTRICTIONS ON THE COMPLEXITY OF THE PROBLEM

All storage arrays in TRAC-PF1 can be dynamically allocated; the only limit on the size of a problem is the amount of central memory available. The number of reactor components in the problem, and the manner in which they are coupled are arbitrary. Reactor components available include accumulators, pipes, pressurizers, pumps, steam generators, tees, valves, and vessels with associated internals.

6. TYPICAL RUNNING TIME

Running time is highly problem dependent and  is a function of the total number of mesh cells, the maximum allowable time-step size, and whether a three-dimensional vessel model is used. If a purely one-dimensional model is used, very large time-steps can be used for slow transients. If a three-dimensional vessel is employed, a material Courant limit in the vessel may reduce the maximum time-step size allowed and increase the running time. Typical computer times for a CDC 7600 average 2-3 ms per time-step per mesh cell. Complete analysis of a detailed PWR LOCA (including reflood) will require several CP hours. The longest running sample problem requires about 70 CP seconds on the CDC 7600, about 300 CPU seconds on the IBM3033, about 1150 CP seconds on a PC  with the 20 MHz 2020+ coprocessor board or about 945 CP seconds with the 25 MHz CPR 2025+ coprocessor board.

7. UNUSUAL FEATURES OF THE PROGRAM

TRAC-PF1 can describe most thermal-hydraulic experiments in addition to a wide variety of light water reactor (LWR) systems. The program is modular to more easily accomodate geometric descriptions of a problem, and more detailed models of physical processes, and to reduce program maintenance costs.

8. RELATED AND AUXILIARY PROGRAMS

Seven auxiliary programs are included with the CDC version of TRAC-PF1. EXCON is a post- processor program used to convert the TRCGRF graphics output file into a set of component data files for input to the general-purpose  graphics program TRAP. GRED and GRIT also process the TRCGRF output  file. CON1 and CON2 convert older TRAC-PD2/MOD1 input decks into the new format required by TRAC-PF1. TRCUPD processes CDC UPDATE statements. These auxiliary programs are dependent upon the computing environment and will need to be replaced or modified for other computing environments. No auxiliary graphics capability is provided with the IBM version of TRAC-PF1.

10. REFERENCES

- Thad D. Knight,
  TRAC-PD2 Independent Assessment,
  NUREG/CR-3866 (LA-10166-MS), December 1984.
- Dean Dobranich, Lawrence D. Buxton, and Chung-Nin Channy Wong,
  TRAC-PF1 LOCA Calculations Using Fine-Node and Coarse-Node Input
  Models,
  NUREG/CR-4044 (SAND84-2305), May 1985.
- Gregory D. Spriggs, Jan E. Koenig, and Russel C. Smith,
  TRAC-PF1 Analysis of Potential Pressurized-Thermal-Shock
  Transients at Calvert Cliffs/Unit 1 A Combustion Engineering PWR,
  NUREG/CR-4109 (LA-10321-MS), February 1985.
- Energy Division, Safety Code development Group,
  TRAC-PF1: AN Advanced Best-Estimate Computer Program for
  Pressurized Water Reactor Analysis,
  NUREG/CR-3567 (LA-9944-MS), February 1984.
- M.A. Viviande:
  Highlights of French Code Assessment Results Obtained in LOBI
  Proc. International ENS/ANS Conf. on Thermal Reactor Safety,
  Vol. 6, 421, pp 2325-2336 (1988) Societe Francaise d'Energie
  Nucleaire (SFEN), Paris.
- I. Szabo and F. David:
Comparative Study by TRAC/PF1 Calculations of Some Typical Natural    Circulation Tests Performed on Scaled Models of a P.W.R.
  Proc. International ENS/ANS Conf. on Thermal Reactor Safety,
  Vol. 6, 421, pp 2372-2381 (1988) Societe Francaise d'Energie
  Nucleaire (SFEN), Paris.
- H. Akimoto et al.:
  Assessment of TRAC-PF1/MOD1 Code for Core Thermal Hydraulic
  Behavior during Reflood with CCTF and SCTF Data
  JAERI -M 93-032 (March 1993).
- A. Ohnuki, H. Akimoto and Y. Murao:
  Assessment of TRAC-PF1/MOD1 and TRAC-PF1/MOD2 Codes for Thermal-
  Hydraulic Behavior in Pressure Vessel during Reflood in SCTF Test
  with an inclined Radial Power Distribution
  JAERI-M 93-138 (July 1993)
- A. Ohnuki, H. Akimoto and Y. Murao:
Assessment of TRAC-PF1/MOD1 Code for Thermal-Hydraulic Behavior in    Pressure Vessel during Reflood in SCTF Test with a Radial Power
  Distribution
  JAERI-M 93-139 (July 1993)

- TRAC - Input Specifications - TRAC-PF1 7.0/EXTUPD 7.6
  LA-TIA-TN-82-1 (June 1982).
- Safety Code Development Group Energy Division (LANL):
  TRAC-PF1 - An Advanced Best-Estimate Computer Program for
  Pressurized Water Reactor Analysis
  NUREG/CR-3567, LA-9944-MS (February 1984).
- B.E. Boyack:
  TRAC-PF1 - Development Assessment
  NUREG/CR-3280, LA-9704-M (July 1983).
- TRAC Newsletter Nr.6 (January 1982).
- TRAC Newsletter Nr.7 (May 1982).

11. MACHINE REQUIREMENTS

CDC 7600 requires approximately 62K words of  small core memory (SCM) and 131K words of large core memory (LCM). The IBM version requires from 4000K to 7000K bytes on an IBM3033. The IBM PC version uses either the DATANAV CPR 2020+ or 2025+ or the plug-compatible DEFINICON DSI 780+ or 785 coprocessor board. The DATANAV coprocessor family is based on the MOTOROLA 68020 micro- processor operating at 16, 20, or 25 MHz with 4, 8, or 16 Mbytes of  RAM and a MOTOROLA 6888X FPU. The CPR 20XX requires 4 Mbytes of RAM  for 300K words of LCM, 8 Mbytes of RAM for 800K words of LCM, and 16 Kbytes of RAM for 1.8M words of LCM.

NEA-DB screened the package on a DELL 466/L PC/80486.

13. OPERATING SYSTEM UNDER WHICH PROGRAM IS EXECUTED

SCOPE 2.1.5 (CDC7600), OS/MVT (IBM370), MVS (IBM3033), DOS 3.2 or later (IBM PC).

14. OTHER PROGRAMMING OR OPERATING INFORMATION OR RESTRICTIONS

COMPASS replacement routines for the TRAC-PF1 linear equation solver are included in the CDC package for more efficient operation. For plotting, TRAP, the CDC version graphics program, makes use of the Integrated Software Systems Corporation's (ISSCO) proprietary software product DISSPLA. The conversion from the CDC to IBM environment was done at Gesellschaft fuer Reaktorsicherheit, West Germany, using an Amdahl 470 V/6 II with IBM MVS operating system and the FORTRAN H Extended Enhanced compiler.

15. NAME AND ESTABLISHMENT OF AUTHOR

   7600     J.H. Mahaffy*
            Energy Division
            Los Alamos National Laboratory
            P. O. Box 1663
            Los Alamos, New Mexico 87545

   370      E.T. Dugan*
            Department of Nuclear Engineering Sciences
            University of Florida
            Gainesville, Florida 32611

   PC       L.A.I. Arrieta*
            Comissao Nacional de Energia Nuclear
            Rio de Janeiro, Brazil
* Contact

File name	File description	Records
NESC0836_10.001	Information file	94
NESC0836_10.002	TRAC-PF1 Fortran source, part 1	13285
NESC0836_10.003	TRAC-PF1 Fortran source, part 2	11862
NESC0836_10.004	TRAC-PF1 Fortran source, part 3	10991
NESC0836_10.005	TRAC-PF1 Fortran source, part 4	9320
NESC0836_10.006	TRAC-PF1 Fortran source, part 5	10155
NESC0836_10.007	TRAC-PF1 Fortran source, part 6	7402
NESC0836_10.008	TRAC-PF1 Fortran source, part 7	12167
NESC0836_10.009	TRAC-PF1 Fortran source, part 8	12854
NESC0836_10.010	Sample problem 1	150
NESC0836_10.011	Sample problem 2	131
NESC0836_10.012	Sample problem 3	131
NESC0836_10.013	Sample problem 4	806
NESC0836_10.014	Sample problem 5	24
NESC0836_10.015	Sample problem 1 output	1552
NESC0836_10.016	Sample problem 2 output	1757
NESC0836_10.017	Sample problem 3 output	2216
NESC0836_10.018	Sample problem 4 output	7254
NESC0836_10.019	DOS file-names	18