Radiation dosimetry for the respiratory tract for uranium miners
Factors affecting the radiation dose to the respiratory tract of uranium miners were investigated. These included atmospheric constitution, deposition of radioactivity in the respiratory tract and physiological translocation. Several aspects of the uranium mine atmosphere were considered, such as radon and radon daughter activity concentrations, physical form and activity-size distribution of the radon daughters, relative humidity and air temperature. Activity concentrations were found to be extremely variable, however, the remaining atmospheric factors were reasonably stable. Less than ten percent of the radon daughters were unattached. The attached fraction could apparently be represented by a mean diffusion coefficient of 1.3 x 10{sup -5} cm{sup 2}/sec or an aerodynamic size of 0.067 microns. This diffusion coefficient was not significantly affected by the presence of atmospheric particles produced during normal mining operations. Total and regional deposition percentages were determined experimentally as well as theoretically. Percent total deposition values for individual radon daughters were 50, 45 and 41 for radium-A, radium-B and radium-C, respectively, for an average respiration rate of 18 min{sup -1} and an average tidal volume of 1.2 liters. The influence of respiration rate and tidal volume upon total deposition was examined. Regional deposition fractions for the nasal cavity, tracheobronchial and pulmonary regions were 22, 15 and 63 percent of the total deposited activity, respectively, for nose-breathing. Physiological translocation of respiratory deposited activity was investigated for various regions of the respiratory system. Results indicated that ciliary translocation was of negligible importance in the dosimetry of inhaled radon daughters.
- Research Organization:
- Colorado State Univ., Fort Collins, CO (United States). Dept. of Radiology and Radiation Biology
- OSTI ID:
- 200384
- Report Number(s):
- COO--1500-15; ON: DE95013629
- Country of Publication:
- United States
- Language:
- English
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