1. NAME AND TITLE

SUBDOSA-II: Calculation of External Gamma-Ray and Beta-Ray Doses from Accidental Atmospheric Releases of Radionuclides.

SUBDOSA was derived from RACER (CCC-174). SUBDOSA-II includes improvements which have been made to the original SUBDOSA.

AUXILIARY ROUTINE

BIVAR: Gamma-Ray Dose Rate Factors for Bivariate Plumes.

DATA LIBRARIES

RMDLIB: Master Data Library.

GISLIG: Gamma-Ray Energy Data Library.

RNDBET: Beta-Ray Energy Data Library.

BIVLIB: Dose Rate Conversion Factor Data Library.

2. CONTRIBUTOR

Battelle Memorial Institute, Pacific Northwest Laboratories, Richland, Washington.

3. CODING LANGUAGE AND COMPUTER

FORTRAN IV; UNIVAC 1100/44.

4. NATURE OF PROBLEM SOLVED

SUBDOSA-II calculates submersion doses from an acute release of radionuclides to the atmosphere, as did SUBDOSA. Doses are calculated as a function of distance from release point, atmospheric stability, and wind speed for a specified radionuclide inventory. Contributions from both beta and gamma radiation are included as a function of tissue depth.

5. METHOD OF SOLUTION

The gamma-ray dose calculation uses the finite cloud approach. Numerical integration over the cloud volume is performed using Bode's rule applied to selected intervals to ensure accuracy.

The effective beta-ray energy for each nuclide is calculated from beta-ray end point energy data. Fermi theory is used to determine the effective beta-ray energy by numerical integration (Simpsons 3/8th rule). The method of Loevenger is used to determine the beta-ray depth-dose reduction factor for tissue.

Nuclide decay is considered with branching to and from isomeric states.

SUBDOSA-II will accept the data library RMDLIB as a master library. The beta-ray energy library and gamma-ray energy library used in SUBDOSA were modified in SUBDOSA-II to use the same radionuclide identifications as the master library.

6. RESTRICTIONS OR LIMITATIONS

Each case has the following dimensional limitations:

Number of Nuclides 500

Number of Gamma-Ray Energy Groups 12

Number of Downwind Distances 10

Number of Beta-Ray Dose Tissue Depths 4

Number of Gamma-Ray Dose Tissue Depths 3

Number of Release Periods 6

7. TYPICAL RUNNING TIME

The running time depends mainly on the number of nuclides in the inventory, the number of release periods and the number of distances. For a typical problem of 10 distances, 1 period, and fewer than 5 nuclides, the running time is 0.3 seconds plus 7 seconds to read the nuclide data libraries plus 2 seconds if a gamma-ray dose rate factor library is read. For 110 nuclides, the dose calculation takes about 7 seconds.

8. COMPUTER HARDWARE REQUIREMENTS

SUBDOSA-II was originally designed to run on the CYBER 74; was made operable on the UNIVAC 1100/44.

9. COMPUTER SOFTWARE REQUIREMENTS

A FORTRAN IV compiler is required.

10. REFERENCES

D. L. Strenge, Informal Note (January 1981).

D. L. Strenge, E. C. Watson, and J. R. Houston, "SUBDOSA: A Computer Program for Calculating External Doses from Accidental Atmospheric Releases of Radionuclides," BNWL-B-351 (June 1975).

11. CONTENTS OF CODE PACKAGE

Included are the referenced document and one (1.2MB) DOS diskette which contains the source code, data libraries, sample problem input and output.

12. DATE OF ABSTRACT

March 1982; updated January 1983; reviewed January 1985.

KEYWORDS: AIRBORNE; FISSION PRODUCTS; REACTOR ACCIDENT; ENVIRONMENTAL DOSE; RADIONUCLIDES; GAMMA-RAY; BETA-RAY; KERNEL; GAUSSIAN PLUME MODEL