Radiation measurements and assessments

Work in the Offsite Measurements Program was directed toward assessments of the radiological impact of inactive uranium mill sites, radiological surveys of former Manhattan Engineering District/Atomic Energy Commission (MED/AEC) facilities throughout the country, and verification of theoretical source terms for effluent releases from a plant designed to recover uranium from wet-process phosphoric acid. During the year, measurements were completed at 22 inactive uranium mills. Activities were directed toward characterization of the spread of contamination from uranium tailings piles, migration of long-lived radionuclides through airborne, aquatic, and terrestrial pathways, and measurements of radon and radon daughters in structures where tailings had been used in construction. It was shown that the highest potential exposure to the general public arises from the diffusion of radon to population centers. Some evidence was found of radium and uranium moving away from a tailings pile where groundwater is active. Initial measurements were made to measure the concentration of uranium in the effluent of a central processing plant designed to recover uranium from phosphoric acid. In addition, uranium concentrations in water and soil on the site of this plant were measured. These measurements will be used along with calculated source terms to evaluate exposure to the public as a result of the operations of this plant