A Fiber Optic Multipass Raman Probe and Instrumentation for Monitoring Flammable Gases in High Level Waste Tanks

79578S The Department of Energy (DOE) has 280 underground tanks used to process and store over 90 million gallons of high-level radioactive chemical waste. The conditions in the tanks are conducive to the formation of flammable gases such as hydrogen, ammonia, and methane, as well as fire accelerants (oxidizers) such as nitrous oxide. An accumulation of these flammable gases above their lower flammability limit (LFL) increases the risk of fire and explosion. To mitigate these risks, this project will deveop an in situ probe capable of detecting concentrations below the LFL. In particular, a Raman instrument with a fiber optic probe head will be developed for deployment inside the tanks, in order to monitor the concentration of these hazardous gases. In Phase I, an efficient multipass Raman gas cell, which will significantly improve the sensitivity of conventional Raman gas measurements, will be built. The cell will be connected via fiber optics to a remote spectrograph/detector. A Raman instrument configuration will be used to determine the cell¿s ability to detect and monitor the concentratioin of selected flammable tank gases. Commercial Applications and Other Benefits as described by the awardee: In addition to the monitoring of underground tanks, the Raman probe should have commercial applications in air pollution monitoring, where the probe could be used for monitoring the release of hazardous gases from industrial sites for regulatory purposes. The Raman probe also could be used in process control, such as in furnace atmosphere control monitoring where the control and monitoring of gases and hydrocarbons are essential.