1. NAME AND TITLE

COMIDA: Radionuclide Food Chain Model for Acute Fallout Deposition.

2. CONTRIBUTOR

Idaho National Engineering Laboratory, EG&G Idaho Inc., Idaho Falls, Idaho.

3. CODING LANGUAGE AND COMPUTER

Fortran 77; IBM PC and compatibles (P00343/MNYCP/00).

4. NATURE OF PROBLEM SOLVED

COMIDA estimates radionuclide concentrations in agricultural food products following an acute fallout event. This dynamic food chain model was implemented in the DOE version of the MELCOR Accident Consequence Code System (MACCS2).

5. METHOD OF SOLUTION

COMIDA uses a fourth order Runge-Kutta solver (Press et al., 1986) with adoptive stepsize control to estimate yearly harvest concentrations for five human crop types (Bq kg-1 crop per Bq m-2 deposited) and integrated concentrations for four animal products (Bq d kg-1 animal product per Bq m-2) for a unit deposition that occurs on any user-specified day of the year. COMIDA is structurally very similar to the PATHWAY model developed by Whicker and Kirchner (1987) and includes the same seasonal transport processes and discrete events for soil and vegetation compartments. Animal product assimilation is modeled using simpler equilibrium models. Differential transport and ingrowth of up to three radioactive progeny (the sample input problems include progeny for 93Mo and 93Nb) are also evaluated.

6. RESTRICTIONS OR LIMITATIONS

Implementations on other platforms requires modification of the source to reference a comparable TIMER subroutine library function call.

7. TYPICAL RUNNING TIME

The approximate run time for each of the four included sample problems was 24 seconds on a Northgate 486/66.

8. COMPUTER HARDWARE REQUIREMENTS

An IBM PC or compatible with a floppy diskette drive and 512K of RAM is required to run the included executable. COMIDA can be installed on DEC VAX, IBM RISC, and CRAY.

9. COMPUTER SOFTWARE REQUIREMENTS

A Fortran 77 compiler is required for implementations on other platforms. The Lahey F77L3/EM32 compiler was used to create the executables included in package.

10. REFERENCE

M. L. Abbott, A. S. Rood, "COMIDA: A Radionuclide Food Chain Model for Acute Fallout Deposition," EGG-GEO-10367, ITER/US/93/TE/SA-2 (November 1993).

11. CONTENTS OF CODE PACKAGE

The referenced document and 1 DS/HD 5.25" (1.2 MB) diskette are included. The DOS diskette contains Fortran 77 source files, executable, sample input and output, and an information file.

12. DATE OF ABSTRACT

June 1994.