Long-term stability of uranium-oxide-based microparticle reference materials: Shelf-life in alcoholic suspension and storage media

For the analysis of individual micrometer- and submicrometer-sized particles collected by International Atomic Energy Agency (IAEA) safeguards inspectors on swipe samples during in-field verification, well-defined microparticulate reference materials are requested by the IAEA for quality control measures. In the safeguards laboratory of the Forschungszentrum Jülich, an aerosol-based process is established to produce well-defined U 3 O 8 microparticulate reference materials according to the IAEA requirements. One of these requirements is the stability of the particles under storage conditions over a certain period. The stability of U 3 O 8 microparticles stored in ethanol was monitored over a period of approximately 4 years indicating some alteration effects. On this basis, systematic shelf-life studies were conducted to understand the interaction of these particles with various storage media over a defined period of time. The paper discusses the first results of shelf-life investigations on U 3 O 8 microparticles in various alcoholic solvents. Graphical abstract