Exploration of Morphologic Signatures of Uranium Tetrafluoride for Nuclear Forensic Science

UF4 is a common feedstock for production of uranium metal and UF6, and open-source publications regarding the morphology of UF4 are limited. Current research has quantitatively demonstrated the utility of uranium oxide morphology to identify experimental variables such as precipitation conditions, thermal history, and storage conditions, among others. We hypothesize similar signatures will be observable in uranium fluorides. Thus, this study investigates morphologic synthetic pathway signatures of UF4 from the ammonium bicarbonate (AUC) and ammonium diuranate (ADU) precipitation routes. Experimentation is ongoing. To develop these signatures, UO2 will be synthesized from both AUC and ADU precipitates, which have largely differing surface areas and morphologies. The UO2 from each synthetic route will be fluorinated using ammonium bifluoride in a fluidized bed reactor to form UF4. Powder X-ray diffraction will be used to confirm the phase purity of the reaction product, while scanning electron microscopy in conjunction with Morphological Analysis of Materials (MAMA) software will be utilized to quantify the material morphology. Additionally, a custom four-factor response surface model design of experiment (DOE) will be used to interpolate between various factors of the fluorination and resulting morphology. Quantifying these material attributes of UF4 is relevant to the morphologic signature for nuclear forensic analyses and nuclear fuels production.