Momeni, and 2 co-authors, reported in late 1979 that uranium concentrate (yellowcake) composites from four mills (Anaconda, Kerr-McGee, Highland, and Uravan) were analyzed for U-238, U-235, U-234, Th-230, Ra-226 and Pb-210.
The overall field study program was intended to:
- Provide measurements that could be used to characterize and to estimate the rates of release of airborne radioactive effluents (source terms) for
uranium milling activities. This would include release rates of radioactive particulates (specific nuclides) and radon-222 from: a) mill stacks and vents, (b) ore piles, and (3) tailings piles. - Provide data that could be used to verify predicted offsite environmental concentrations of radionuclides based on source terms and dispersion
calculations. - Provide data that could be used to evaluate the potential radiological significance of food ingestion pathways for airborne effluents released
from uranium mills, focusing primarily on ingestion exposures associated with grazing animals and locally raised food crops or garden produce. - Serve as a means to test, demonstrate, and evaluate environmental monitoring methods and techniques in order to provide information that could be used in the development of guidance for monitoring programs.
As one part of this broad field study program, measurements were made in order to characterize the particulate emissions and release rates from yellowcake packaging and drying stacks. The results are presented in this report. Uranium mill concentrate (yellowcake) from active operating mills was analyzed for U-238, U-235, U-234, Th-230, Ra-226, and Pb-210 by radiochemical methods. The results are interpreted and correlated with stack discharge measurements made by Fort (1979) using isokinetic sampling procedures.
A brief description of the milling processes associated with the mills where data were collected and details of the procedures for radiochemical analysis are also included.
The authors concluded that the ratio of specific activities of U-238 to U-234 in the composites suggested that secular radioactive equilibrium exists in the ore. The average activity ratios in the yellowcake were determined to be 2.7 x 10- 3 (Th-230/U-238), 5 x 10-4 (Ra-226/U-238) and 2 x 10-4 (Pb-210/U-238).
Based on earlier EPA measurements of the release rates from the stacks, the amount of yellowcake released was determined to be 0.1% of the amount processed.
Other reference citation: https://www.osti.gov/biblio/5643221
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