1. NAME AND TITLE

RADRISK: Estimates Radiation Doses and Health Effects from Inhalation or Ingestion of Radionuclides.

The RADRISK code has been developed as a synthesis of two previously existing computer codes: CCC-392/INREM II, developed at ORNL, and CAIRD, developed by the EPA (EPA 520/4-78-012, 1978). The version of RADRISK included in this package has numerous minor differences from that described in the reference document, but the basic code structure remains unchanged. One important difference in the input data requirements is that ``Respiratory Lymph'' is no longer required as a mandatory source and target tissue; rather, lymph activity is now included in computing dose to lung. The dosimetric and health effects data base output on unit 25 is read as input by DARTAB which is included in CCC-476/CAAC.

2. CONTRIBUTORS

Oak Ridge National Laboratory, Oak Ridge, Tennessee.

Royal Observatory of Hong Kong, Kowloon, Hong Kong.

3. CODING LANGUAGE AND COMPUTER

Fortran IV; IBM 3033 (A). Fortran 77; Data General MV (B).

4. NATURE OF PROBLEM SOLVED

Radioactive materials deposited in human tissues emit energy as they decay. This may be absorbed by the tissue possibly resulting in biological damage, such as the development of cancer. RADRISK estimates radiation dose rates to various human organs from inhalation or ingestion of radioactive materials, and the health effects in a reference population as a result of this exposure.

5. METHOD OF SOLUTION

The amount of radioactive material present in various organs as a function of time is computed by solving a set of differential equations. This activity is multiplied by dosimetric S factors to compute the dose rate. The dose rates over the lifetime of the cohort are then processed through a life-table actuarial analysis to estimate incremental cancer deaths in the cohort, taking into consideration all competing risks.

6. RESTRICTIONS OR LIMITATIONS

None noted.

7. TYPICAL RUNNING TIME

Running time will depend on the nature of the exposure case of concern. Illustrative examples for the IBM 3033 version are given below for a wide range of radionuclides; each case consists of chronic inhalation of the given radionuclide over the lifetime of the cohort. Pu-239 has no radioactive progeny that contribute significantly to dose over the lifetime of the cohort, while Pb-210 decays to Bi-210 and Po-210, and Ra-226 decays through a chain of 8 radioactive progeny which contribute to doses. Some example cases include: Pu-239, which with 1 significant radionuclide in the decay chain took 1.5 seconds of cpu time, Pb-210 with 3 significant radionuclides in the decay chain took 3 cpu seconds, and Ra-226 with 9 significant radionuclides in the decay chain took 20 cpu seconds. RADRISK requires 16 cpu seconds to compile, 1 cpu second to link and the sample problem executed in 5 cpu seconds on the IBM. The sample problem for the DG version took about 5 minutes on the MV 4000.

8. COMPUTER HARDWARE REQUIREMENTS

RADRISK compiles and executes in 350 K on the IBM 3033. The source was converted from IBM using the Data General MV 20000. The sample case was tested by RSIC without modification of the source on the MV 4000.

9. COMPUTER SOFTWARE REQUIREMENTS

An IBM OS/VS Assembler and Fortran H Extended Enhanced compiler are required. The operating system for the IBM 3033 used for testing is the IBM OS/VS2. On the Data General, the Fortran 77 compiler is required under AOS/VS.

10. REFERENCES

a. Included in the documentation:

D. E. Dunning, Jr., R. W. Leggett, and M. G. Yalcintas, "A Combined Methodology for Estimating Dose Rates and Health Effects from Exposure to Radioactive Pollutants," ORNL/TM-7105 (December 1980).

b. Background information:

R. E. Sullivan, N. S. Nelson, W. H. Ellett, D. E. Dunning, Jr., R. W. Leggett, M. G. Yalcintas, and K. F. Eckerman, "Estimates of Health Risk from Exposure to Radioactive Pollutants, ORNL/TM-7745 (1981).

11. CONTENTS OF CODE PACKAGE

Included are the referenced document (10.a) and one (1.2MB) DOS diskette which contains the source code and sample problem input and output.

12. DATE OF ABSTRACT

March 1984, revised August 1988.