RSICC CODE PACKAGE PSR-481
1. NAME AND TITLE
TRAC‑PF1: Best‑Estimate Analysis PWR LOCA.
2. CONTRIBUTOR
Comissao Nacional de Energia Nuclear (CNEN), Rio de Janeiro, RJ (Brazil).
Los Alamos National Laboratory, New Mexico (United States).
3. CODING LANGUAGE AND COMPUTER
FORTRAN 77 for IBM PC XT and AT (P00481IBMPC00).
4. NATURE OF PROBLEM SOLVED
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.
TRAC-PF1 was developed on a CDC computer at Los Alamos National Laboratory. The PC version of TRAC‑PF1 was converted at CNEN in 1989 and has not been updated since that time. The NRC no longer supports the TRAC codes. They currently develop and maintain the TRACE code system, which is the TRAC/RELAP Advanced Computational Engine. TRACE is a modernized thermal-hydraulics code designed to consolidate the capabilities of NRC's 3 legacy safety codes - TRAC-P, TRAC-B and RELAP. This is NRC's flagship thermal-hydraulics analysis tool. See the website for more information http://www.nrccodes.com/.
5. 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.
6. RESTRICTIONS OR LIMITATIONS
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.
7. 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.
IBM-PC: Complete analysis of a detailed PWR LOCA (including reflood) required several CP hours on an IBM PC AT. The longest running sample problem required about 300 seconds on a PC with the 20 Mhz 2020+ coprocessor board or about 945 CP seconds with the 25 Mhz CPR 2025+ coprocessor board.
8. COMPUTER HARDWARE REQUIREMENTS
IBM-PC: Records indicate that the PC version ran on an 80386 PC under DOS and required a coprocessor. This version was initially run with the DATANAV CPR 2020+ or 2025+ or the plug compatible DEFINICON DSI 780+ or 785 coprocessor board. The DATANAV coprocessor family was based on the MOTOROLA 68020 operating at 16, 20, or 25 Mhz with 4, 8, or 16 Mbytes of RAM and a MOTOROLA 6888X FPU.
9. COMPUTER SOFTWARE REQUIREMENTS
IBM-PC: The PC implementation was done under DOS 3.2 using the SVS (Silicon Valley Software) Fortran 77 compiler. No executables are included in the package. The code has not been modified to compile on newer systems and was released (for archival purposes) as it was received in September 1989. Modifications will be required to compile and run this code.
10. REFERENCES
a) Included w/package:
Safety Code Development Group, Energy Division at 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 Developmental Assessment,” NUREG/CR-3280 (LA-9704-M) July 1983.
Safety Code Development Group, Energy Division at Los Alamos National Laboratory, “Input Specifications - TRAC-PF1 7.0/EXTUPD 7.6,” LA-TIA-TN-82-1 (June 1982).
TRAC Newsletter Nr.6 (January 1982).
TRAC Newsletter Nr.7 (May 1982).
b) Background references:
D. R. Liles and J. H. Mahaffy, “TRAC-PF1/MOD1 An Advanced Best-Estimate Computer Program for Pressurized Water Reactor Thermal-Hydraulic Analysis,” NUREG/CR-3858 (April 1987).
J.C. Ferguson and M.R. Turner, “TRAP: Plotting Package for TRAC, Revision of NUREG/CR‑2054,” (LA‑8709‑MS), rough draft, received (August 1981).
11. CONTENTS OF CODE PACKAGE
Included are reference documents in 10.a above and software on CD-ROM in a Windows file created with WinZIP. Software includes source, sample problems, control information, and auxiliary information. No executables are included in package.
12. DATE OF ABSTRACT
November 2005.
History: Abstract for the CDC7600 version of TRAC-P1A was first distributed by NESC in December 1979 and later transferred to ESTSC. Other versions were distributed by NESC in the 1980s, but RSICC could not recover these versions. The IBM PC version was submitted September 1989 and released AS‑IS by the ESTSC July 1993; it was transferred to RSICC and re-released in November 2005 for archival purposes. No modifications were made to the code package at either ESTSC or RSICC.
KEYWORDS: REACTOR SAFETY; LWR; THERMAL HYDRAULICS; LOCA