The Department of Energy (DOE) currently is undertaking the enormous task of remediating defense wastes and environmental damages that have occurred over 50 years of weapons production. Significant technological advances are needed to characterize, process, and store highly radioactive waste and to remediate contaminated areas. Aside from the processing and waste form issues, analytical technologies needed for the characterization of solids and for monitoring storage tanks and contaminated sites do not exist or are labor intensive. The sensitive and rapid analysis of organics, inorganics, and transuranic radioactive wastes in contaminated soils, groundwater, and tank wastes is a key need.
The objective of this project was to develop general and sensitive techniques for determining the molecular speciation of organics and inorganics in tank wastes and those chemisorbed on mineral soil substrates. These methods need to be sensitive to a broad spectrum of compounds to detect the many species present in mixed hazardous/radioactive waste environments. Development of multiphoton-ionization techniques was required to satisfy the critical need for sensitive and rapid detection of technetium-99 and strontium-90. Compared to current methods which require weeks, laser analysis can be completed in hours. This research addressed the needs in both basic and applied research categories and helped determine the design parameters and evolution of field analytical platforms.
Laser-based analysis techniques, primarily laser ablation mass spectroscopy (LAMS) and matrix-assisted laser desorption ionization (MALDI), were evaluated for chemical speciation of complex waste samples. Laser ablation can vaporize nearly any solid material in pulsed plumes of sufficient concentration for detailed analysis by mass spectrometry, laser-induced fluorescence, and other techniques. The LAMS approach couples laser vaporization with ultra-sensitive mass spectrometry. Analysis of even complex, multi component mixtures can be performed rapidly and requires very little sample. When the concentrated laser ablation plumes are combined with multiphoton-ionization, time-of-flight mass spectroscopy, the result is a versatile and sensitive analysis technique of very high mass resolution which provides superb differentiation between compounds of similar masses and between isotopes. In addition, the resonant ionization process can provide excellent spectral resolution which extends and complements the mass resolution.
General and sensitive techniques were developed to determine the molecular speciation of organics and inorganics found in tank wastes and chemisorbed on mineral soil substrates. This project was completed in FY 1997.
These technologies increased the capabilities to analyze mixed radioactive and hazardous waste. The results are useful in performing the analysis of tank and crib wastes, contaminated soils, and groundwater. The near real-time analysis capabilities of these methods are also important for monitoring waste retrieval, facilities decontamination, and other site restoration actions. It contributed to the success of the DOE/Hanford Mobile Analytical Reconnaissance System program which was predicted to result in a savings of $30-75 million during the first 3 years following its implementation.