RSICC CODE PACKAGE CCC-689

1. NAME AND TITLE

2. CONTRIBUTORS

Battelle Memorial Institute, Columbus, Ohio, through the Energy Science and Technology Software Center, Oak Ridge, Tennessee.

3. CODING LANGUAGE AND COMPUTER

FORTRAN 5; CDC CYBER170 (C00689CDCMF00).

4. NATURE OF PROBLEM SOLVED

MATADOR analyzes the transport and deposition of radionuclides as vapor or aerosol through Light Water Reactor (LWR) containments during severe accidents and calculates environmental release fractions of radionuclides as a function of time. It is intended for use in system risk studies. The principal output is information on the timing and magnitude of radionuclide releases to the environment as a result of severely degraded core accidents. MATADOR considers the transport of radionuclides through the containment and their removal by natural deposition and the operation of engineered safety systems such as sprays. Input data on the source term from the primary system, the containment geometry, and thermal-hydraulic conditions are required.

5. METHOD OF SOLUTION

The containment is modeled as a series of interconnected control volumes. In each control volume, radionuclides can be in any of four different states: suspended in the atmosphere, deposited on the walls, picked up by spray water droplets, or residing in bulk water in the sump or on the containment floor. If the physical form of the radionuclides is aerosol, these states are further divided into size classes. Radionuclides can also be picked up and collected by engineered safety systems such as filters, ice condensers, and pressure suppression pools. Radionuclides can transfer from one state to another within each compartment as a result of processes such as deposition on the walls or spray water droplet pickup. They can also transfer from one compartment to another through inter-compartmental flows. A linear first-order differential equation is written for each species in each state and control volume to account for the transfer of species between states in a control volume or between control volumes. These equations are assembled into a matrix equation and solved simultaneously using the matrix expansion technique with scaling. The aerosol agglomeration and gravitational settling calculations are done in series over each time-step using the moments approach. The discrete aerosol size distribution is converted to a log-normal distribution for agglomeration calculations. After these calculations, it is converted back into a discrete distribution for transport calculations over the next time-step. Care is taken to conserve the total aerosol mass as well as individual species masses between conversions. The time-step size is regulated so that the two sets of calculations do not unduly affect each other.

6. RESTRICTIONS OR LIMITATIONS

Maxima of 10 interconnected control volumes, 10 chemical species, 10 kinetic transport processes and 10 discrete size classes for aerosols. Application is limited to LWR systems. Noble gases are assumed to simply transfer in phase with the fluid.

7. TYPICAL RUNNING TIME

A typical problem covering 1 hour of accident time without or with sprays operating requires 8 or 50 CP seconds, respectively, on a CDC CYBER180/855. Execution time increases by a factor of 1.5 on a CDC CYBER74 and by a factor of 6 on a CDC CYBER73.

8. COMPUTER HARDWARE REQUIREMENTS

MATADOR requires, without segmentation, approximately 335,000 (octal) words of central memory (SCM) and 116,000 (octal) words of extended core storage (ECS).

9. COMPUTER SOFTWARE REQUIREMENTS

NOS 2.3; NOS/BE 2.2; NOS 2.2.

10. REFERENCES

a) Included in documentation:

P. Baybutt, S. Raghuram, and H.I. Avci, "MATADOR: A Computer Code for the Analysis of Radionuclide Behavior During Degraded Core Accidents in Light Water Reactors," NUREG/CR-4210 (BMI-2125) (April 1985).

H.I. Avci, S. Raghuram, and P. Baybutt, "MATADOR (Methods for the Analysis of Transport and Deposition of Radionuclides) Code Description and User's Manual," NUREG/CR-4211 (BMI-2126) (April 1985).

b) Background information:

H. Jordan, J.A. Gieseke, and P. Baybutt, "TRAP-MELT User's Manual," NUREG/CR-0632 (BMI-2017) (February 1979).

R.O. Wooton, P. Cybulskis, and S.F. Quayle, "MARCH 2 (Meltdown Accident Response Characteristics) Code Description and User's Manual," NUREG/CR-3988 (BMI-2115) (September 1984).

Lynn T. Ritchie, Jay D. Johnson, and Roger M. Blond, "Calculations of Reactor Accident Consequences Version 2 CRAC: Computer Code User's Guide," NUREG/CR-2326 (SAND81-1994) (February 1983).

11. CONTENTS OF CODE PACKAGE

Included in the package are the referenced documents in (10a.) And one diskette which includes source and test case written in both UNIX and DOS formats.

12. DATE OF ABSTRACT

February 2000.

KEYWORDS: ENVIRONMENTAL DOSE; REACTOR SAFETY; RISK ASSESSMENT