TIR-Raman Sensor for Characterizing Nuclear Waste Slurries 22a

Efficiently vitrifying slurries, such as is stored in wells at nuclear waste sites, into a solid glass for safe stabilization and storage requires accurately measuring its chemical composition. Current measurement methods are slow and labor-intensive, and are not checked for radioactive exposure. The slurry must be sampled for transport to a laboratory while it is filtered, tested, and analyzed. While Raman spectroscopy has shown promise for automating such measurements, its use has been limited to clear liquids, as it is not accurate in the turbid slurry that is typical of nuclear waste. Statement of how this problem is being addressed. An innovative method is proposed for total internal reflection dual-wavelength Raman spectroscopy, with spectral normalization for turbidity so that it is accurate for a turbid slurry. The slurry is passed through a flow cell equipped with a Raman probe connected by fiber optic cables to a remote laser and spectrometer. This flow cell lends itself to use in an in situ low-maintenance Raman analyzer system that can run unattended for extended periods, continuously measuring and recording chemical concentrations What is to be done in Phase I? The proposer has already demonstrated that total internal reflection Raman spectroscopy can be used to quantify chemical concentration in turbid solutions over certain chemical concentration ranges. The recorded signal was shown to be independent of temperature and turbidity level, achieved through spectral normalization. In Phase I, the proposer will build on their previous Raman spectroscopy work by further developing the spectral normalization procedure, and by dual-wavelength compensation to suppress the broad Raman background, to improve reproducibility, accuracy, precision, and sensitivity over wider ranges of turbidity and chemical concentration. Commercial Applications and Other Benefits The proposed automated low-maintenance system with the capability to test turbid nuclear waste for chemical content in situ will greatly reduce costs and increase the safety of storing and processing the waste, and will reduce the chances of it leaking into the environment. The same benefits can be realized for other wastewater treatment, as already confirmed by end users in the wastewater treatment industry, where the chemical content of influent wastewater must be monitored to detect and address root causes of irregular release of toxic chemicals into the environment. The need for rapid testing of nuclear and other wastewater content becomes particularly important in emergencies such as flooding, earthquake, and accidents.