United States Nuclear Regulatory Commission - Protecting People and the Environment

TRAC-M Programmer's Guide: Fortran 77 Version 5.5 (NUREG/CR-6658)

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Publication Information

Manuscript Completed: October 1999
Date Published: December 1999

Prepared by:
R.G. Steinke, S.J. Jolly-Woodruff, J.W. Spore

Los Alamos National Laboratory
Los Alamos, New Mexico 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 W6245

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The Transient Reactor Analysis Code (TRAC) was developed to provide advanced best-estimate predictions of postulated accidents in light-water reactors. The TRAC-M program provides this capability for pressurized water reactors and for many thermal-hydraulic test facilities. The code features a one- (1-), two- (2-), and three-dimensional

(3D) treatment of the pressure vessel and its associated internals. The code includes a two-fluid nonequilibrium hydrodynamics model with a noncondensable-gas field and solute tracking, flow-regime-dependent constitutive equation treatment, optional reflood tracking capability for bottom- and top-flood and falling-film quench fronts, and a consistent treatment of the entire accident sequences, including the generation of consistent initial conditions. The stability-enhancing two-step numerical algorithm is used in the 1-, 2-, and 3D hydrodynamics, and permits violation of the material Courant limit. This technique permits large timesteps, hence the running time for slow transients is reduced.

TRAC-M has a heat-structure (HTSTR) component and a radiation heat-transfer model that allows the user to model heat transfer accurately for complicated geometries. An improved reflood model based on mechanistic and defensible models has been added. TRAC-M also contains improved constitutive models and additions and refinements for several components.

This manual is the third volume of a four-volume set of documents on TRAC-M. This guide was developed to assist the TRAC-M programmer and contains information on the TRAC-M Version 1.10+ code and data structure, the TRAC-M calculational sequence, and memory.

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