1. NAME AND TITLE

AIRGAMMA: A Program For The Calculation Of External Exposure To Gamma Rays From A Radioactive Cloud.

2. CONTRIBUTOR

Japan Atomic Energy Research Institute, through NEA Data Bank, France.

3. CODING LANGUAGE AND COMPUTER

Fortran 77 and IBM Assembler; IBM 3083.

4. NATURE OF PROBLEM SOLVED

AIRGAMMA calculates the external exposure to gamma rays from a radioactive cloud.

5. METHOD OF SOLUTION

Cloudshine doses are calculated by interpolating normalized doses based on the Gaussian plume model. The normalized dose is defined as the dose on the ground when a gamma-emitting nuclide is released at a rate of 1 Ci/hr or the amount of 1 Ci and the wind speed is 1 m/sec. The code takes into account the depletion of the dispersing materials for calculation of the cloudshine doses, but ignores effects of the building wake and the mixing layer.

6. RESTRICTIONS OR LIMITATIONS

None noted.

7. TYPICAL RUNNING TIME

The sample input problems (1, 2, 3) were tested on the IBM 3083 at NEA Data Bank. Problem 1 took 1.27 seconds; problem 2 took 26.54 seconds; problem 3 took 169.51 seconds.

8. COMPUTER HARDWARE REQUIREMENTS

AIRGAMMA runs on the IBM 3083 and FACOM-M380.

9. COMPUTER SOFTWARE REQUIREMENTS

The code was written in Fortran IV and was modified by NEA Data Bank to Fortran 77. On the IBM 3083, the compiler used was VS Fortran Level 2.1.1 and the IBM Assembler.

10. REFERENCES

a. Included in the documentation:

"User's Manual For the AIRGAMMA Computer Code," NEA 1130/01 (December 12, 1986).

b. Background information:

A. Hidaka, and Toshinori Iijima. "AIRGAMMA: A Computer Code For Quick Assessment Of The Cloudshine Doses Due To Accidental Releases Of Radioactive Materials," Hoken Butsuri, 20, 33 (1985), Japan. [In Japanese].

11. CONTENTS OF CODE PACKAGE

Included are the referenced document and one (1.2 MB) DOS diskette.

12. DATE OF ABSTRACT

December 1990.