A fieldable instrument for waterborne radionuclide detection

What is it about?

In monitoring effluent water leaving its sites, the United States Department of Energy (DOE) assays for alpha-emitting radionuclides (uranium and the transuranics) to ensure compliance with regulatory limits. Because alpha emissions can only be detected over a short range in water (- 40 Jlm), the conventional approach is to collect samples for processing in a central laboratory; a time-consuming and costly procedure ensues to separate and measure the radionuclides. Because ofthe sporadic nature of sampling processes, there is the possibility that a release may go undetected. We are addressing this issue by developing a real-time, field-deployable instrument. This device incorporates a proprietary film that selectively binds radionuclides from dilute aqueous samples. By combining the film with an appropriate alpha spectrometer, we have developed a fieldable system that can operate as an autonomous monitor in a batch or continuous manner. Laboratory results to date have been encouraging. Positive identification of uranium and plutonium has been made by resolving the energy spectrum of emitted alphas. Sensitivity for uranium is at the 10 part per trillion level (15 femtocuries per liter).

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Why is it important?

Normally, a sampling team is sent out, a (ground water/surface water/effluent) water sample is taken and logged, the sample (and replicates) is/are acidified and refrigerated, and then transported to an accredited lab for analysis. Analysis results are available approximately 2 weeks post-sampling. This device provided on-line, real-time (20 minute) analysis result to below the EPA-specified limits for alpha-emitting radionuclides, In addition, the instrument produced a CD- or DVD- sized record of the analyte sample, which provided capability for post-analysis verification of the analysis.

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