1. NAME AND TITLE

CAAC: Code System for Implementation of Atmospheric Dispersion Assessment Required by the Clear Air Act.

AUXILIARY ROUTINES

DARTAB: Code for combining radionuclide environmental exposure data with dosimetric and health effects data.

AIRDOS-EPA: Estimates radiation doses caused by airborne radionuclides around nuclear facilities.

PREPAR: A user-friendly preprocessor to create AIRDOS-EPA input data sets.

PREDA: Preprocessor to create DARTAB input data sets.

RADFMT: Converts RADRISK.BCD to binary.

DATA LIBRARY

RADRISK.BCD: A file of dose and risk factors for 502 radionuclides written with RADRISK for use with DARTAB. The data used for 1984 CAA assessments includes 50- and 70-year internal dose factors.

2. CONTRIBUTORS

Oak Ridge National Laboratory, Oak Ridge, Tennessee.

Westinghouse Materials Company of Ohio, Cincinnati, Ohio.

3. CODING LANGUAGE AND COMPUTER

Fortran IV; IBM 3081 (C00476I303300) and Fortran 77; VAX (C00476D0VAX00).

4. NATURE OF PROBLEM SOLVED

The Clean Air Act Codes (CAAC) implement the radiological assessment methodology used for the preparation of the Environmental Protection Agency 1984 Background Information Documents on Radionuclides. Atmospheric dispersion and deposition are calculated by AIRDOS-EPA. Dose and risk assessment tables are calculated by DARTAB from the binary output file produced by AIRDOS-EPA and a file of dose and risk factors calculated by RADRISK. Preprocessors (PREPAR and PREDA) for AIRDOS-EPA and DARTAB access data bases of element and nuclide dependent data to simplify the execution of the principal programs.

5. METHOD OF SOLUTION

AIRDOS-EPA implements a long term average Gaussian Plume model. The associated terrestrial model for deposition is based on NRC Regulatory Guide 1.109. The 70-year dose factors for DARTAB are calculated by RADRISK and, in general, are consistent with those in ICRP-30. Risks are calculated using a linear Life Table model consistent with BEIR-3. The resultant risk factors are 280.5 cancer deaths per 106 person rad (low LET) and 700 cancer deaths per 106 person working-level-months exposure to radon decay products.

6. RESTRICTIONS OR LIMITATIONS

Programs are limited to 36 radionuclides and to 20 downwind distances for each of 16 compass directions. Memory Regions for execution on an IBM 3081 system under MVS are as follows:

PREPAR 1008 K

AIRDOS-EPA 716 K

PREDA 148 K

DARTAB 668 K

7. TYPICAL RUNNING TIME

A complete run, including PREPAR, AIRDOS-EPA, PREDA, and DARTAB, for an individual and population assessment requires approximately 1 and 2 minutes of CPU time, respectively, on an IBM 3081 processor.

8. COMPUTER HARDWARE REQUIREMENTS

CAAC is operable on the IBM 3033 and VAX computers.

9. COMPUTER SOFTWARE REQUIREMENTS

The IBM version compiled under OS/VS2 using the IBM VS compiler and language level 66. The VAX version uses a Fortran 77 compiler under the VMS operating system.

10. REFERENCES

C. L. Begovich, K. F. Eckerman, E. C. Schlatter, S. Y. Ohr, R. O. Chester, "DARTAB, A Program to Combine Airborne Radionuclide Environmental Exposure Data with Dosimetric and Health Effects Data to Generate Tabulations of Predicted Health Impacts," ORNL-5692 (August 1981).

R. E. Moore, C. F. Baes III, L. M. McDowell-Boyer, A. P. Watson, F. O. Hoffman, J. E. Pleasant, and C. W. Miller, "AIRDOS-EPA: A Computerized Methodology for Estimating Environmental Concentrations and Dose to Man from Airborne Releases of Radionuclides," ORNL-5532 (June 1979). Andrea L. Sjoreen and Charles W. Miller, "PREPAR - A User-Friendly Preprocessor to Create AIRDOS-EPA Input Data Sets," ORNL-5952 (August 1984).

J. G. Darst, "User's Manual for CCC-476A/CAAC or CCC-476B/CAAC AIRDOS-EPA Codes AIRDOS and PREPAR," Westinghouse Materials Company Informal Report (September 1987).

11. CONTENTS OF CODE PACKAGE

Included are the referenced documents and one DS/HD 3.5-in. (1.44 MB) diskette in self-extracting compressed DOS files which contains the source codes and data libraries, plus output from the sample problem.

12. DATE OF ABSTRACT

August 1985, September 1985, November 1986, November 1987.

KEYWORDS: AIRBORNE; ENVIRONMENTAL DOSE; GAUSSIAN PLUME MODEL; INTERNAL DOSE; NUCLIDE TRANSPORT; RADIOLOGICAL SAFETY.