RSICC CODE PACKAGE CCC-680

1. NAME AND TITLE

UMIBIO: Code System to Model Uranium Mills Bioassay Dosimetry.

2. CONTRIBUTORS

Nuclear Regulatory Commission, Washington, DC through the Energy Science and Technology Software Center, Oak Ridge, Tennessee.

3. CODING LANGUAGE AND COMPUTER

FORTRAN 77; IBM3081 or 3033 (C00680I303300).

4. NATURE OF PROBLEM SOLVED

UMIBIO is an internal dosimetry model developed for estimation of the urinary concentration of natural uranium excreted at various times after an inhalation exposure to yellowcake (dried at high and at low temperatures) or ore dust. Calculations are based either on the single exposure intake variable or for continuous exposure on the intake rate variable. The user may change the default intake variables, specify single versus continuous exposure and one or both exponential terms for the systemic calculations.

5. METHOD OF SOLUTION

UMIBIO uses the model developed by the Task Group on Lung Dynamics of the International Commission on Radiological Protection (ICRP) to describe the deposition and retention of inhaled radioactive material in the human respiratory tract and its clearance into the blood. The metabolic model assumes that 11 percent of the uranium reaching the blood is deposited in kidney tissues and is subsequently excreted with a 15-day half-life. It is also assumed that 67 percent of the uranium reaching the blood is excreted within 24 hours without being deposited in any organ. The systemic uptake by all other organs is 22 percent; this uranium is subsequently released back to the blood in accordance with a power function which may be represented by the sum of two exponential functions as recommended in ICRP-30.

6. RESTRICTIONS OR LIMITATIONS

Maximum of 40-day time interval between specimen collections. Subsequent excretion of the uranium redeposited in organs other than the kidney, about 4 percent of that initially reaching the blood, is ignored.

7. TYPICAL RUNNING TIME

Each sample problem required less than 5 CPU seconds on an IBM9672.

8. COMPUTER HARDWARE REQUIREMENTS

1500 Kbytes of memory are required for compilation and execution on an IBM. It was tested at RSICC on IBM9672.

9. COMPUTER SOFTWARE REQUIREMENTS

UMIBIO was developed under MVS on IBM3033 and under VM/CMS on IBM4331. It also runs under MVS/ESA with VS Fortran 2.5.0.

10. REFERENCES

a) Included in documentation:

R. E. Alexander, R. B. Neel, J. S. Puskin, and A. Brodsky, "Internal Dosimetry Model for Applications to Bioassay at Uranium Mills," NUREG-0874 (July 1986).

b) Background information:

International Commission on Radiological Protection, "Limits for Intakes of Radionuclides by Workers," ICRP Publication 30, Pergamon Press, New York (July 1978).

International Commission on Radiological Protection, "Recommendations of the International Commission on Radiological Protection," ICRP Publication 26, Pergamon Press, New York (January 1977).

11. CONTENTS OF CODE PACKAGE

Included in the package are the referenced document in (10.a) and one 3.5" diskette written in DOS format, which includes source file, JCL and test case input and output.

12. DATE OF ABSTRACT

November 1999.

KEYWORDS: INTERNAL DOSE; RADIONUCLIDES