Radon Exhalation from Uranium Mill Tailings Piles -Description and Verification of the Measurement Method.

摘要

Uranium mill tailings piles result in several sources of radiation exposure. These exposures are primarily from concentrations of the uranium progeny thorium-230,radium-226,and radon-222in the tailings. Radon-222and its progeny are a source of external gamma and lung exposure. Using the accumulation technique,field measurements of the radon flux from uranium mill tailings were made at three mills and at one experimental plot. The sample collection technique,method of calculating results,and reproducibility of the technique are described. The exhalation data (fCi/sq cm-sec) reveal that reproducibility is within about 10percent and that the variation is less than the uncertainty associated with the linear regression analysis of the accumulated radon concentration versus time. Long term measurements (greater than about 8hours) result in accumulated concentrations that approach the radon concentrations in the surface soil gas,and invalidate the assumptions inherent in the accumulation technique.