Comparison of active and passive environmental sampling for safeguards applications

Environmental sampling (ES) of surfaces using cotton swipes at nuclear facilities is one of the standard sampling protocols used by International Atomic Energy Agency (IAEA) inspectors to verify treaty compliance. Described herein is a series of studies undertaken to (1) survey a variety of low latent uranium content sampling media for efficacy of collecting nuclear materials and (2) compare active collection of particulates to swipe sampling. Findings from the evaluation of 40 natural and synthetic woven swipes will be presented. Results from a joint Oak Ridge National Laboratory (ORNL) and Savannah River National Laboratory (SRNL) project wherein a variety of passive deposition surfaces and active collections were examined for efficacy of sampling uranium processing effluents will also be detailed. For the swipe material evaluation portion of this work, uranium (U) particulate collection efficiency was evaluated on woven materials as-received and coated with complexants/solvents. The relative merits of each sampling matrix were reviewed on the basis of: (1) latent U background, (2) ease of separating the swipe material from the nuclear components, (3) presence of isobaric interferences from the swipe, and (4) efficiency in collecting uranium from contaminated surfaces. The second series of experiments evaluated the collection characteristics of active aerosol collection versus swipe sampling. ORNL and SRNL are collaborating on the development of the next generation of ES equipment for air grab and constant samples that could become an important addition to the international nuclear safeguards inspector's toolkit. Described herein are findings from the evaluation of collection efficiency of swipe sampling and active collection using an aerosol contaminant extractor (ACE) developed by SRNL. (author)