Fluorometry of UO₂²⁺Ion in Nitric Acid Solutions

Abstract

The UOi+ fluorescence spectra were measured for solutions whose conditions, except for coexisting species, corresponded to high level waste (HLW) solutions in the nuclear fuel reprocessing plants. From these spectra it was ascertained that the U concentration can be determined in the range of 2-200 g/m3 with an accuracy of 1 g/m3 at 30--40°C. The UO;' fluorescence was influenced significantly by the temperature. The apparant activation energy of the temperature effect was 35.7 kJ/mol. The fluorescence intensities increased with nitric acid concentration in the range of 0.75-4.5 mol/dm3. The temperature effect was considered to be caused by a chemical process concerned with water molecules.

Simultaneous quantification of uranium(vi), samarium, nitric acid, and temperature with combined ensemble learning, laser fluorescence, and Raman scattering for real-time monitoring

“…One form of optical spectroscopy, time-resolved laserinduced fluorescence spectroscopy (TRLIFS), was evaluated extensively for monitoring PUREX streams (e.g., raffinate) several decades ago, [7][8][9][10][11] but little work has been done in the last decade. More recently, Raman spectroscopy and UV-Vis spectrophotometry have been evaluated for monitoring appli-cations, although these options are orders of magnitude less sensitive to uranium(VI) concentration than TRLIFS.…”