Evaluation of instrumental methods for the measurement of yellowcake emissions

An evaluation of current sampling and analysis methods used for monitoring yellowcake emissions from uranium mill exhausts was performed by Pacific Northwest Laboratory. The representativeness of sampling once per quarter was felt to be questionable. A more representative sample would be obtained by a continuous sampling system. The analysis could be performed by relatively newer instrumental methods. Direct-spectrometric and isotopically excited x-ray fluorecence instrumental analysis methods were evaluated. Because of a redirection in funding, the evaluation was not completed in terms of identifying instrumental interferences and field testing of the chosen methods. However, in light of readily available technology, a preferred method for sampling and analysis of yellowcake from uranium mill exhausts is proposed. This method would sample the exhaust stacks continuously using a continuous, automatic, isokinetic stack sampler with deposition of the exhaust gas particulates onto filter paper. The deposited particulates would then be analyzed by x-ray fluorescence using /sup 57/Co as an excitation source. It is also recommended that a paper-tape sampler that houses an isotopic excitation source and detector be interfaced to a continuous stack sampler. This system would require evaluation and field testing after development. 16 references, 6 figures, 3 tables.