1. NAME AND TITLE

AREAC: Radiological Emission Analysis Code System.

AREAC is based to a large extent on CCC-242/AIREM, both of which were developed as a part of a comprehensive dose calculational system for the analysis of emissions and effluents from the nuclear fuel cycle.

2. CONTRIBUTOR

U.S. Environmental Protection Agency, Washington, D. C.

3. CODING LANGUAGE AND COMPUTER

Fortran IV; IBM 370/3033.

4. NATURE OF PROBLEM SOLVED

AREAC was designed to calculate potential radiological impact of atmospheric releases of radionuclides from area sources. It represents an initial attempt at developing a quantitative model for analyzing the potential radiological impact of airborne, constant, continuous releases of gaseous radionuclides from area sources (principally inactive uranium tailings piles). It can calculate radionuclide concentrations and individual inhalation doses at up to six specific receptor locations and at up to 192 general locations around an area source. Population doses can also be calculated.

AREAC is useful for more accurately assessing close-in doses from large area sources, such as uranium mill tailings piles. Results are more accurate than those calculated with existing air pathway models.

5. METHOD OF SOLUTION

AREAC accounts for area source shape, cloud diffusion, ground and inversion-lid reflections, and radionuclide decay by time-of-flight. It is dose model independent and requires a dose conversion factor as part of input data to calculate doses proportional to radionuclide concentrations.

AREAC consists of two main parts. In the first part, a sector-averaged Gaussian diffusion equation is utilized to calculate radionuclide dispersion coefficients (X/Q's), radionuclide concentrations, and resultant inhalation yearly doses at up to six specific receptor locations in the vicinity of an area source. These, in practice, would correspond to the maximally exposed individuals identified to be living near the pile. In the second part, the same diffusion equation is employed to calculate radionuclide dispersion coefficients, concentrations, and yearly doses and population doses for 16 wind sectors and up to 12 downwind distances (192 sector-segments) around the area source. The user can specify the shape of the area source (rectangular or circular) and the degree of accuracy in accounting for the distributed nature of the source.

6. RESTRICTIONS OR LIMITATIONS

None noted.

7. TYPICAL RUNNING TIME

AREAC runs in about 12 seconds on an IBM 370 computer.

8. COMPUTER HARDWARE REQUIREMENTS

AREAC is operable on the IBM 370 or IBM 3033 computers. When utilized to its maximum capacity, it requires 48 K bytes of storage space.

9. COMPUTER SOFTWARE REQUIREMENTS

A Fortran IV compiler is required.

10. REFERENCE

D. Michlewicz, "Area Source Radiological Emission Analysis Code (AREAC)," ORP-EAD-76-6 (October 1976).

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 1983; revised September 1983.