The International Atomic Energy Agency routinely performs the collection and analysis of environmental samples from declared nuclear facilities as part their international nuclear safeguards mission. The samples typically contain actinide-bearing particulates which are generated from facility activities. Secondary ion mass spectrometry (SIMS) is the primary analytical method used for the trace particulate characterization for these environmental samples. Although reference uranium oxide powders are available to support SIMS QA/QC, from both US and European government sponsored suppliers, they lack the desired monodisperse micron-sized characteristics and have limited isotopic compositions. Particulate materials with well characterized size, chemical/structural composition, and tailored isotopic content are needed for international proficiency testing and microanalytical method development activities. SRNL has engineered a production tool capable of synthesizing the required uranium particles called the monodisperse particle production and collection system (MPPaCS). The system can produce highly monodisperse uranium-bearing particulates with tailored diameters between 0.5-5 microns and was engineered with in situ particle characterization capabilities, via an aerodynamic particle sizer. Generated particles are collected either by electrostatic precipitation with an SRNL-built collector or by impaction via commercial tools. To date, uranium particulates have been produced as UO<sub>3</sub> hydrate or uranyl oxalate dependent on MPPaCS operational parameters and feedstock chemical composition. Post production, the characterization of test particulates has been done with Raman spectroscopy, SEM/EDS, and SIMS. Related calculation methods have been developed to solve the optimization problem of feedstock generation via mixed ratio of certified reference materials. Future efforts will be discussed and include the development of plutonium and mixed actinide particle production methods.

Production and characterization of uranium-containing particles for nuclear safeguard applications

2019 Fall National Meeting

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