An Optical Spectroscopy Investigation of Environmental Effects on Uranium Oxyfluoride Particles
EMSL Project ID
37800
Abstract
Uranium oxyfluoride (UO2F2) is the first metastable hydrolysis product of uranium hexafluoride (UF6), an important chemical in the uranium separation process as well as a trace impurity in WF6, which is commonly used in the manufacture of integrated circuits. Due to the high reactivity of UF6 to moisture, moisture in air is sufficient to initiate hydrolysis and after formation of UO2F2 [1], slowly loses all the fluorine atoms in the molecule. Investigation of the rate of fluorine loss is important in nuclear forensic investigations. Understanding how environmental conditions might affect this rate of change can verify whether a facility is compliant with a facility or State declaration under IAEA safeguards [2]. In this project, UO2F2 particles were previously deposited on various substrates including sapphire, zinc selenide and graphite, and then exposed to pre-defined levels of UV-light, humidity, and temperature. After different exposure times, samples were harvested and analyzed by optical and mass spectrometric techniques to determine the composition, morphology, and structure of the uranium-bearing particles. Based on the kinetics of ageing this information may be used to estimate duration of environmental exposure. Optical spectroscopy techniques, including cryogenic laser-induced time-resolved U(VI) fluorescence microspectroscopy (CLIFS) and FT-IR/Raman spectroscopy will be used to deduce the molecular structure of the uranium oxyfluoride particles. Other more conventional techniques including scanning electron microscopy-energy dispersive x-ray fluorescence (SEM-EDX) and secondary ion mass spectrometry (SIMS) will be used to monitor loses of fluoride in the molecular structure as a function of the time and sample treatment conditions.
Project Details
Project type
Limited Scope
Start Date
2009-10-21
End Date
2009-12-21
Status
Closed
Released Data Link
Team
Principal Investigator
Team Members