| Year of Award: | 1998 |
| Amount of Award: | $760,000 |
| Problem Area: | High Level Waste |
| Science Category/SubCategory: | Analytical Chemistry and Instrumentation / Sensors and Techniques |
| Lead Principal Investigator: | Dr. Richard F. Haglund, Jr. 6301 Stevenson Vanderbilt University Nashville, Tennessee 37235 615-322-7964, richard.haglund@vanderbilt.edu |
| Principal Investigator at Pacific Northwest National Laboratory: | Dr. Wayne P. Hess Pacific Northwest National Laboratory P. O. Box 999 Richland, Washington 99352 509-376-9907, wayne.hess@pnl.gov |
| For More Information: | |
| Other EMSP Research: |
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Description Provided by Investigator:
The Department of Energy faces a major challenge in characterizing, managing and eventually transforming or disposing of high-level radioactive wastes stored at its Hanford, Oak Ridge and Savannah River sites. Atomic and molecular characterization of these wastes is critical to maintaining and assuring workers and the public about the safety and appropriateness of every step in environmental remediation, from hazard assessment to final disposal.
Laser mass spectrometry techniques have, in principle, the capability to provide rapid, accurate characterization of complex materials at the pico- or even femtomolar sensitivity level - a capability which would dramatically reduce the sample quantities required for accurate characterization of waste material and which would also make possible on-line monitoring of waste streams. This, in turn, would make it substantially easier and cheaper to avoid personnel safety hazards, flammable or explosive chemical reactions, and threats to tank integrity. However, analytical techniques now available do not yet provide quantitative information for this task.
We propose to develop protocols for quantitative analysis of tank waste materials based on the use of tunable infrared ultrashort-pulse lasers. Our goals are to:
• Demonstrate atomic, molecular and substrate characterization in model solids by laser desorption-ionization (LDI) and matrix-assisted (MA) LDI mass spectrometry;
• Develop the capability for generating quantitative anlayses by measuring the total energy budget and identifying the principal reaction channels in LDI and MALDI-MS and use this information to benchmark appropriate models for the procedures.
• Following the demonstration of these protocols in model materials, demonstrate their applicability to complex heterogeneous tank wastes from the Hanford site.
The research will be carried out by a team effort of Vanderbilt University and Pacific Northwest National Laboratory investigators who have already been collaborating for two years.
The detailed tasks in the research plan presented here are based on preliminary studies which show that:
• sub-picosecond infrared laser pulses can be wavelength-tuned to optimize desorption and ionization while minimizing fragmentation and the amount of material removed;
• matrix-assisted laser desorption and ionization of several small molecules appears to show fewer adducts and less matrix interference in the infrared than in the ultraviolet;
• the use of ultrafast tunable laser pulses in LDI and MALDI provides greated specificity and sensitivity than is available from nanosecond la
These experimentally demonstrated results show that having the capability critical to generating the scientific base of information needed to develop realistic waste characterization.
This research program has the potential for significant impact within the framework of the Environmental Management Science Program. It provides important benefits in critical areas:
• Detection of molecular species in a way which can provide information about reactivity and abundance, at high sensitivity;
• A coordinated effort to study both model materials - which can lead to computational benchmarks of the analytical procedures - and realistic samples of tank waste;
• Quantative emphasis of extracting reaction rates, branching ratios, and absolute budgets for sample size and laser inputs required for successful analysis.
Moreover, the protocols have significant promise for translation into field-deployable instrumentation and procedures for real-time monitoring of waste-stream processing.
The full list of Environmental Management projects that could potentially be addressed by awards such as this one, which deals with High Level Waste problems, are listed in the Index of High Cost Environmental Management Projects by Problem Area, in the back of this appendix, under the heading "High Level Waste".