RSICC CODE PACKAGE CCC-685
1. NAME AND TITLE
UDAD: Uranium Dispersion & Dosimetry Model.
2. CONTRIBUTORS
Argonne National Laboratory, Argonne, Illinois, through the Energy Science and Technology Software Center, Oak Ridge, Tennessee.
3. CODING LANGUAGE AND COMPUTER
Fortran IV (94%); PL/I (4%); and Assembly language (2%); IBM370 (C00685/I0370/00).
4. NATURE OF PROBLEM SOLVED
The Uranium Dispersion and Dosimetry (UDAD) program provides estimates of potential radiation exposure to individuals and to the general population in the vicinity of a uranium processing facility such as a uranium mine or mill. Only transport through the air is considered. Exposure results from inhalation, external irradiation from airborne and ground-deposited activity, and ingestion of foodstuffs. Individual dose commitments, population dose commitments, and environmental dose commitments are computed. The program was developed for application to uranium mining and milling; however, it may be applied to dispersion of any other pollutant.
5. METHOD OF SOLUTION
The removal of radioactive particles from a contaminated area such as uranium tailings by wind action is estimated from theoretical and empirical wind-erosion equations according to the wind speed, particle size distribution, surface roughness, and other parameters. Atmospheric concentrations of radioactivity from specific sources are calculated by means of a dispersion, deposition, resuspension model. Source depletion as a result of deposition, fallout of the heavier particulates, and radioactive decay and ingrowth of radon daughters are included in a sector-averaged, Gaussian plume dispersion model. The average air concentration at any given receptor location is assumed to be constant during each annual release period, but to increase from year to year because of resuspension. Surface contamination is estimated by including buildup from deposition, ingrowth of radioactive daughters, and removal by radioactive decay, weathering, and other environmental processes. Deposition velocity is estimated on the basis of particle size, density, and physical and chemical environmental conditions which influence the behavior of the smaller particles. Calculation of the inhalation dose to an individual is based on the ICRP Task Group Lung Model (TGLM). Estimates of the dose to the bronchial epithelium of the lung from inhalation of radon and its short-lived daughters are calculated based on a dose conversion factor from the BEIR report. External radiation exposure includes radiation from airborne radionuclides and exposure to radiation from contaminated ground. Terrestrial food pathways include vegetation, meat, milk, poultry, and eggs. Internal dosimetry is based on ICRP recommendations, with the option of using either a single or a multiple exponential retention model.
6. RESTRICTIONS OR LIMITATIONS
A maximum of 80 sources may be specified. The UDAD default is 240 receptor locations corresponding to the intersections in a grid pattern of 16 wind sectors and 15 radial distances. Any set of 0-15 distances in the range 0.1 to 99.9 km. may be selected. In addition to these regular receptors, 0-60 selected extra receptor locations may be specified as input by the user. A complete set pf stability wind-rose data must be specified. This consists of 576 frequency values -- a combination of 6 stability categories, 16 wind directions, and 6 wind speed classes. For particular pollutants, up to five particles sizes and five size distributions may be specified for use in the population dose calculations.
7. TYPICAL RUNNING TIME
The sample problem was executed in 8 minutes on an IBM370 at NESC in 1979. UDAD was tested on IBM 370 when it was first released by NESC in 1979. It was not retested or modified with it was transferred to RSICC and released in 2002.
8. COMPUTER HARDWARE REQUIREMENTS
430K bytes of memory are used.
9. COMPUTER SOFTWARE REQUIREMENTS
Software requirements include OS/370 Operating system; Fortran IV Compiler and PL/I compiler, Assembler, DISSPLA.
10. REFERENCES
a: included in documentation:
M. H. Momeni, Yuchien Yuan, and A.J. Zielen, "The Uranium Dispersion and Dosimetry (UDAD) Code," NUREG/CR-0553, ANL/ES-72 (May 1979).
Information on Assembler Routine for UDAD IX.
b: background information:
C.J. Smith and W.J. Cody, "ANL-AMD System 360 Subroutine ANLQ054S, DATE, current data in Gregorian calendar," (February 1968); Final Environmental Statement, Bear Creek Project, U. S. Nuclear Regulatory Commission, Office of Nuclear Materials Safety and Safeguards, Docket No. 40-8452, NUREG-0129 (June 1977).
NESC Note 79-57, "UDAD, NESC No. 8 24.370 Tape Description (July 1979).
11. CONTENTS OF CODE PACKAGE
Included in the package are the references in 10.a and a DOS-formatted 3.5" diskette which contains source codes, JCL, and test case input. No executables are included with the package.
12. DATE OF ABSTRACT
March 2002.
KEYWORDS: AIRBORNE; EXTERNAL DOSE; INTERNAL DOSE; RADIONUCLIDES