1. NAME AND TITLE

BUSH: A Code to Calculate Radiation Doses Inside Buildings from Routine Releases of Radionuclides to the Atmosphere.

2. CONTRIBUTOR

Oak Ridge National Laboratory, Oak Ridge, Tennessee.

3. CODING LANGUAGE AND COMPUTER

Fortran IV; IBM 360/370.

4. NATURE OF PROBLEM SOLVED

BUSH implements models to study the effect of man's residence time inside building structures on radiation doses from routine releases of radionuclides to the atmosphere. Both internal dose from inhaled radionuclides and external photon dose from airborne and surface deposited radionuclides are considered. For each pathway, the code calculates a dose reduction factor, which is the ratio of the dose to a reference individual inside the building to the corresponding dose with no building present. Calculations can be performed for arbitrary mixtures of radionuclides released to the atmosphere.

5. METHOD OF SOLUTION

Internal dose reduction factors are calculated by assuming a constant radionuclide concentration in the atmosphere outside a building structure. The indoor radionuclide airborne concentration is obtained by solving a first-order linear differential equation which accounts for air ventilation and deposition on inside surfaces of the building.

Building shielding effects for external photon exposure from airborne and ground-deposited radionuclides are estimated using the point-kernel integration method including buildup. For ease of calculation, a hemispherical building shape is assumed.

For both internal and external dose reduction factors, the models are formulated in terms of parameters which are specified by the user (e.g., air ventilation rate, deposition velocity, wall thickness) for the particular calculation of interest.

6. RESTRICTIONS OR LIMITATIONS

The number of radionuclides in the source term is limited to 75 and the number of photons per radionuclide is limited to 300. For a given set of calculations, the number of different values for each input parameter is limited to 10.

7. TYPICAL RUNNING TIME

For calculations using a single set of input parameter values, the running time on the IBM 360/91 computer is less than 1 minute. For calculations involving several sets of input parameter values, running times up to 5 minutes may be encountered. These estimates are based on source terms containing about 40 radionuclides.

The sample problem ran in 1.32 seconds on the IBM 360/91.

8. COMPUTER HARDWARE REQUIREMENTS

BUSH is operable on the IBM 360/370 computers. The GO step requires 72 K of storage.

9. COMPUTER SOFTWARE REQUIREMENTS

A Fortran H compiler is required. Standard I/O is used.

10. REFERENCE

D. C. Kocher, "Effects of Man's Residence Inside Building Structures on Radiation Doses from Routine Releases of Radionuclides to the Atmosphere," ORNL/TM-6526 (December 1978).

11. CONTENTS OF CODE PACKAGE

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

12. DATE OF ABSTRACT

January 1982.