The Stability of Uranium Microspheres for Future Application as Reference Standard in Analytical Measurements

Synthesis of size-controlled UO2 microspheres from the hydrothermal conversion of U(iv) aspartate

“…First of all, as UO 2 and (U,Pu)O 2 solid solutions are aimed to be used as fuels in future Gen III and/or Gen IV reactors 2 , spherical oxides with tailored size could help to improve the flowing capability of powders used in the fabrication process 3,4 and could enhance the green density of the pellets before the sintering step. The design of uranium oxides particles with controlled shape and size is also required to qualify the analytical methods used for nuclear safeguards 5,6 . Uranium oxide nanospheres have already attracted some attention in view of their catalytic properties, particularly in the framework of the destruction of volatile organic compounds 7 .…”

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

“…The stability of U 3 O 8 microparticles in different suspension media was already investigated by Middendorp et al [6,13]. The selection of suitable solvents mainly depends on (i) the commercial availability with high degree of purity, (ii) high detachment efficiency of particles from the substrate, (iii) high chemical stability of particles in the solvent, (iv) low tendency of particles to agglomerate in the solvent, and (v) moderate boiling point for the controlled evaporation during the suspension step.…”

“…The selection of suitable solvents mainly depends on (i) the commercial availability with high degree of purity, (ii) high detachment efficiency of particles from the substrate, (iii) high chemical stability of particles in the solvent, (iv) low tendency of particles to agglomerate in the solvent, and (v) moderate boiling point for the controlled evaporation during the suspension step. From those solvents investigated by Middendorp et al [13]., ethanol is the most suitable suspension media based on the selection criteria. Particularly, the stability of the particles in ethanol over a period of 432 days without significant dissolution (i.e., the measured uranium concentration of the filtered particle suspension was below the detection limit of the mass spectrometric device) is a strong argument for the selection of ethanol as suspension media [6,10].…”

Hydrothermal synthesis of homogenous and size-controlled uranium-thorium oxide micro-particles for nuclear safeguards

“…Beyond wet chemistry routes, alternative methods based on pyrolysis techniques were also tested. Particularly, the IEK-6 group at FZ Julich (Germany) has developed for several years the synthesis of U3O8 micro particles (potentially doped with Nd 3+ ) with a size of around 1 µm in diameter, mechanically controlled from the diameter of the droplets formed in the aerosol by vibrating orifices [17][18][19][20].…”