Online, Real-Time Analysis of Highly Complex Processing Streams: Quantification of Analytes in Hanford Tank Sample

Processing of hazardous materials is a crucial example where online monitoring can significantly reduce operation risk, cost, and time. This is particularly true in the case of the Hanford site, where nuclear materials from the Cold War era are being processed for environmental cleanup efforts. In exceedingly complex streams such as those at Hanford, online and real-time monitoring can be challenging due to the complexity of instrument signals. Further obstacles are imposed by the caustic nature of processing streams, as well as the radiation damage inflicted on instruments and probes. Online monitoring based on Raman spectroscopy enables the detection of many Hanford tank species of interest. Nine chemical species that comprise the majority of tank waste by volume, including Al­(OH)4 –, C2O4 2–, CO3 2–, CrO4 2–, NO3 –, NO3 –, OH–, PO4 3–, and SO4 2–, were detected and quantified. Real-time analysis of Raman signal allows for immediate quantification of target analytes and was successfully accomplished through the use of chemometric models. Furthermore, irradiation tests revealed that Raman monitoring systems can effectively continue to operate even after receiving 1 × 107 rad of γ dose. The online, real-time monitoring system developed here was successfully used to simultaneously quantify nine target analytes in a real sample collected from Hanford tank AP-105.