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

Production of mixed element actinide reference particulates to support nuclear safeguards using THESEUS, an aerosol-based particulate synthetic methodology

“…This may be related to a reduction in uranium oxide crystalline character. Another explanation for the Raman peak broadening is a loss in crystallite size, 23 which correlates to the increased surface roughness observed for the 10% Th particles over the 1% Th particles (Fig. 7).…”

“…4 demonstrates a reconciliation of density between various Th concentrations, wherein a convergence of APS and APM-SEM measured values predicts a density of 5.6 g cm −3 for the 10% Th sample. The nature of the material phase for the 10% Th/U particulates is speculative, but the formation of Thoria (ThO 2 ) 23 and/or mixed uranium-thorium oxides is likely. For example, prior reports for the Th–U–O ternary phase system, at higher concentrations of thorium, show a mixed-phased material, such as a combination of U 3 O 8 and Th x U ( x −1) O y , may be formed within an individual particle.…”

“…[16][17][18][19] Recent R&D efforts have focused on transitioning uranium oxide production technologies to the synthesis of mixed actinide-bearing particulates with targeted lanthanide compositions, [20][21][22] and Th/U-oxide particles. 23 Savannah River National Laboratory (SRNL) has developed a mixed actinide oxide phase particle production platform to meet end user physical and analytical requirements. Prior, SRNL has explored various particulate synthesis parameters, such as calcination temperature, feedstock concentration, ratios of feedstock solutions, and aerosol generation, which improved production.…”

Synthesis and Morphological Control of UO2F2Particulates

“…Data for particle size distributions were obtained by individually approximating the Feret diameter of adequately spherical particles using ImageJ software. An example of such measurements can be found in the recent work of Asplanato et al 52 …”