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Title: Investigation of the degree of equilibrium of the long-lived uranium-238 decay-chain members in airborne and bulk uranium-ore dusts

Technical Report ·
OSTI ID:5074515

The degree of disequilibrium among /sup 238/U decay chain members in some airborne dusts and typical ores has been established by precise radiochemical analyses. This information is necessary to evaluate the lung dose model currently used for estimating the effect of the inhalation of uranium ore dust. The particle size distributions of airborne decay chain components in dusts at one uranium mill have been investigated. Statistically significant disequilibria were observed for /sup 230/Th, /sup 226/Ra, and /sup 210/Pb in both airborne dusts and composite ore samples. With the exception of ore from one mill in the United States, most of the daughter concentrations in powdered ore composites were within 10% of /sup 238/U. In airborne dusts, the concentration of /sup 226/Ra was typically below /sup 238/U; the minimum /sup 226/Ra concentration observed for airborne ore dusts was 56% of equilibrium. A statistically significant particle size dependence was observed for /sup 226/Ra//sup 238/U ratios in several airborne dusts collected at a uranium mill.

Research Organization:
Pacific Northwest Lab., Richland, WA (USA)
DOE Contract Number:
AC06-76RL01830
OSTI ID:
5074515
Report Number(s):
NUREG/CR-1895; PNL-3696; ON: DE82020897
Country of Publication:
United States
Language:
English