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Huckabay, Heath A.

Publications and source records attributed to Huckabay, Heath A..

Analysis of Environmental Swipes Using Fluorescence Microscopy - Summary Report

This report summarizes efforts as part of a collaboration between Oak Ridge National Laboratory (ORNL) and the University of Kansas (KU) during fiscal year 2016 for the purpose of screening environmental swipes (ESs) using fluorescence microscopy. The overall goal of this work is to image actinide-bearing species by exploiting the fluorescence properties of the uranyl moiety. If successfully developed, this capability would permit automated screening of actinide species in environmental swipes to prioritize samples for destructive analysis. The evaluation of efforts to date has shown that uranyl fluoride can be imaged using fluorescence microscopy and the vibronic structure can be resolved; however, difficulties arise when attempting to image these materials on ESs because of spectral interference. Due to the fluorescence decay differences between cellulosic fibers and uranyl-containing materials, time-gating approaches were investigated to minimize this interference. This approach shows promise; however, the technique requires additional developmental work before it can be transitioned to a robust method for laboratory use.

54 ENVIRONMENTAL SCIENCES↗

Technologies for pre-screening IAEA swipe samples

During the course of International Atomic Energy Agency (IAEA) inspections, many samples are taken for the purpose of verifying the declared facility activities and identifying any possible undeclared activities. One of these sampling techniques is the environmental swipe sample. Due to the large number of samples collected, and the amount of time that is required to analyze them, prioritizing these swipes in the field or upon receipt at the Network of Analytical Laboratories (NWAL) will allow sensitive or mission-critical analyses to be performed sooner. As a result of this study, technologies were placed into one of three categories: recommended, promising, or not recommended. Both neutron activation analysis (NAA) and X-ray fluorescence (XRF) are recommended for further study and possible field deployment. These techniques performed the best in initial trials for pre-screening and prioritizing IAEA swipes. We learned that for NAA more characterization of cold elements (such as calcium and magnesium) would need to be emphasized, and for XRF it may be appropriate to move towards a benchtop XRF versus a handheld XRF due to the increased range of elements available on benchtop equipment. Promising techniques that will require additional research and development include confocal Raman microscopy, fluorescence microscopy, and infrared (IR) microscopy. These techniques showed substantive responses to uranium compounds, but expensive instrumentation upgrades (confocal Raman) or university engagement (fluorescence microscopy) may be necessary to investigate the utility of the techniques completely. Point-and-shoot (handheld) Raman and attenuated total reflectance–infrared (ATR-IR) measurements are not recommended, as they have not shown enough promise to continue investigations.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

Technology recommendations for pre-screening of IAEA swipe samples

Argonne and Oak Ridge National Laboratories have prepared an analysis of recommended, possible, and not recommended technologies for pre-screening and prioritizing IAEA swipes. The analytical techniques listed under the recommended technology list are the most promising techniques available to date. The recommended list is divided into two sections: Argonne’s recommended techniques and Oak Ridge’s recommended techniques. This list was divided based upon the expertise of staff in each subject area and/or the instrumentation available at each laboratory. The following section, titled Possible Techniques, is a list of analytical techniques that could be used for pre-screening and prioritizing swipes if additional instrumentation and effort were provided. These techniques are not necessarily top priority, but should not be discounted for future or expanded efforts. Lastly, a list of not recommended techniques is provided to outline the analytical methods and instrumentation that were investigated by each lab but deemed not suitable for this task. In addition to the recommendation list, a short procedure is provided outlining the steps followed for destructive analysis by the Network of Analytical Laboratories (NWAL) for determination of uranium concentrations, isotopic content of sample and swipe. Swipes generated for this project will be given to ORNL’s NWAL laboratory for analysis after analysis by other techniques at both laboratories.

98 NUCLEAR DISARMAMENT, SAFEGUARDS, AND PHYSICAL P↗