United States Nuclear Regulatory Commission - Protecting People and the Environment

TRAC-M/F77, Version 5.5 Developmental Assessment Manual (NUREG/CR-6730)

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Publication Information

Manuscript Completed: June 2001
Date Published: July 2001

Prepared by:
B.E. Boyack, J.F. Lime, D.A. Pimentel,
J.W. Spore, J.L. Steiner

Los Alamos National Laboratory
Los Alamos, NM 87545

F. Odar, NRC Project Manager

Prepared for:
Division of Systems Analysis and Regulatory Effectiveness
Office of Nuclear Regulatory Research
U.S. Nuclear Regulatory Commission
Washington, DC 20555-0001

NRC Job Code K6892

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Los Alamos National Laboratory has developed the Transient Reactor Analysis Code (TRAC) to provide advanced, best-estimate simulations of real and postulated transients in pressurized water reactors (PWRs) and for many related thermal-hydraulic facilities. The modernized TRACM/F77, Version 5.5, is the latest release version. The previous release code, TRAC-PF1/MOD2, Version 5.4, was modified by removing nonstandard FORTRAN constructs to produce a standard FORTRAN 77 (F77) code. In the process, a more uniform programming style was established. TRAC-M/F77 (1) is more portable and maintainable than Version 5.4; (2) retains TRAC's essential features, a one- and/or threedimensional, two-fluid treatment for the thermal hydraulics; (3) has other necessary modeling capabilities to model a reactor system; and (4) has a newly enhanced reflood model.

This Developmental Assessment Manual describes the TRAC-M/F77, Version 5.5, assessment calculations that were compared with analytical calculations and experimental data. The manual is issued in two volumes. Volume I contains the assessment sections, and Volume II contains the appendices. The appendices to the manual include the input listings of the assessment problems, and code-data comparision of assessments exercised with different reflood, grid spacer, and noding modeling options. The comparisons were performed to determine the accuracy and applicability of TRAC-M/F77. Based on these assessments against analytical solutions, separate-effects tests, and integral tests, we believe that TRAC-M/F77 is a viable calculational tool for analyzing PWRs during a loss-of-coolant accident and operational transients. In addition, the developmental assessment calculations demonstrate that TRACM/F77 is applicable to a wide range of test facilities and is accurate in terms of predicting major trends.

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