In-situquantification of dispersity and sphericity of uranyl nitrate sol dropletsusing holographic imaging

Uniform-sized and highly spherical nuclear fuel microspheres are pivotal components in high-temperaturegas-cooled reactors. In the manufacturing process of microspheres through external gelation, monodisperseddroplets with high sphericity at the dispersion stage establishes the fundamental basis for the subsequentproduction of superior-quality microspheres. Addressing the monitoring requirements for droplet size andsphericity in dispersion process, this study develops a measurement apparatus based on digital in-lineholography. The apparatus records droplet holograms within distances ranging from 96 mm to 183 mm,achieving imaging resolutions between 64 lp/mm to 32 lp/mm. Droplet measurements are conducted for nine operational conditions encompassing varied excitation frequencies and liquid flow rates. Observationunder various dispersion parameters reveals diverse droplet morphologies. Polydisperse conditions manifestan abundance of satellite droplets, agglomerated droplets, coalesced droplets, and deformed droplets. Thestatistical results indicate that at 100 Hz, monodisperse droplets with high sphericity are produced, exhibiting astandard deviation below 30 mu m. Moreover, droplet sizes demonstrate a deviation from theoretical calculationswithin 2.5%. Additionally, preliminary measurements are conducted during the dispersion process of a six-nozzle head, confirming the accuracy on locating droplets of the holographic system within a depth range ofmore than 30 mm