1. NAME AND TITLE

TACT-III: Calculation of the Transport of Radioactivity from a Reactor Core.

AUXILIARY ROUTINE

Nuclide data pre-processor to convert from BCD to binary format.

2. CONTRIBUTORS

Oak Ridge National Laboratory, Oak Ridge, Tennessee.

U. S. Nuclear Regulatory Commission, Washington, D. C.

3. CODING LANGUAGE AND COMPUTER

Fortran IV; IBM 370/3033.

4. NATURE OF PROBLEM SOLVED

TACT-III (an acronym for ``Transport of ACTivity") is one of a series of codes developed for the purpose of evaluating the mitigating effects of engineered safety features. It has been applied to analyses of light water reactors with a data base consisting of iodines and noble gases.

TACT-III is a computational vehicle for representing a mathematical model by a system of ordinary differential equations and calculating a numerical solution of the differential equations. It is not a model, itself, nor is it tied to a fixed set of source terms or other parameter values.

5. METHOD OF SOLUTION

TACT-III simulates the movement of radioactivity released from a reactor core as it migrates through user-defined regions (nodes) of the containment, is immobilized by filters and sprays, and leaks to the outside environment. The user's input data specify a dynamic compartment model which is represented by systems of ordinary differential equations with constant coefficients. The equations are solved explicitly by matrix transformation methods. TACT-III carries out the integration of these systems of equations over a succession of contiguous time intervals following reactor shutdown, with the interval boundaries corresponding to transitions of system parameter values. Outputs are shown for the end of each time interval and include the level of radioactivity in each node of the containment and in the environment, broken down as iodines, noble gases, and solids, and the radiation dose to reference individuals at the exclusion radius, the boundary of the low population zone, and in the control room. Values of input parameters are also printed and a summary is available at the user's option.

6. RESTRICTIONS OR LIMITATIONS

Data are required from two sources: (1) input data from the user which varies from one run to another according to the analysis to be made and (2) a permanent data base which normally does not change from one run to another but which can be regenerated to include new data. System parameter values must be constant within each time interval.

7. TYPICAL RUNNING TIME

The sample problems tested required < 10 seconds each.

8. COMPUTER HARDWARE REQUIREMENTS

TACT-III is operable on the IBM 370/3033 computers. A typical case requires 840 K bytes of core storage.

9. COMPUTER SOFTWARE REQUIREMENTS

A Fortran Q (H extended enhanced) compiler is required. TACT-III uses the IBM OS/MVS JES2 system.

10. REFERENCE

G. G. Killough, C. L. Begovich, A. L. Sjoreen, L. W. Bell, "A Guide for the TACT III Computer Code," NUREG/CR-3287, ORNL/TM-8763 (May 1983).

11. CONTENTS OF CODE PACKAGE

Included are the referenced document and one (1.2MB) DOS diskette which contains the source code and sample problem input and output.

12. DATE OF ABSTRACT

January 1984.