February 2004

DIAL's Research Highlights

Diagnostic Instrumentation & Analysis Laboratory
Mississippi State University
John Plodinec, Principal Investigator

Prepared for the U.S. Department of Energy
Office of Science and Technology
Cooperative Agreement DE-FC01-04EW54600

Task 1

Support of Closure Sites

Accelerating Phytoremediation by Monitoring Plant Status

We received the cold vapor AAS results for the mercury samples we sent to State Chemical Lab. The results are consistent with our ICP-AES results. We will digest and analyze the large batch of plant and soil samples from last year's mercury phytoremediation experiments. One of our manuscripts, "Distribution, transformation and bio availability of trivalent and hexavalent chromium in contaminated soil" was accepted for publication in Plant and Soil. We have also been processing data and writing papers based on our previous phytoremediation experiments.

Task 2

Support of Hanford Single Shell Tank Waste Disposition

In-tank/At-tank Characterization for Closure of Hanford Tanks

Stereovision. During February, the DIAL stereovision effort concentrated on preparing a scientific journal paper describing our state-of-the-art system. As part of an on-going dialog with Hanford, DIAL has been provided by Hanford with the specifications for in-tank cameras; this information will enhance our ability to better address Hanford's needs.

Microwave-induced plasma-cavity ringdown spectroscopy. Due to our dependence upon pulsed laser systems, a few parts in our pulsed laser systems have to be fixed or replaced. After the scan controller portion of the dye laser was fixed, a leak was discovered in the internal cooling system of the Nd:YAG laser head. The laser head was shipped back to the manufacturer for repair; and the experimental work was temporarily stopped. During this period, our efforts were focused on the revision of a manuscript about evaluation of the compact microwave-induced plasma source using emission spectra of uranium as indicators. This work was submitted to the journal Spectrochimica Acta B. The experimental work will resume once the repaired laser head is received.

Fiber optic sensors. Zinc sulfide, ZnS, is an inorganic scintillation agent used for gamma-ray detection. A single-piece optical fiber made from sol-gel silica doped with ZnS has been made. The ZnS in the sol-gel silica gives bright yellow fluorescence when excited with a mercury lamp.

Fourier transform profilometry. The DIAL Fourier transform profilometry (FTP) effort completed work on manufacture of new control cables for the new camera system. Software development for the new camera control and image acquisition software was also completed. Work continued on designing/prototyping a new camera housing and the rotary joint in the robotic FTP-probe for the 4-in. risers on Hanford waste tanks. A mock-up of a light-weight insertion arm was prototyped and critiqued as part of our design effort. Modification of the design is dependent upon obtaining a more detailed knowledge of deployment details at Hanford. The search for sources for bright utility and projector lights continued as did work on the control cable manufacture and the software development for the new camera control and image acquisition software. Our efforts on image quality improvement continued.

Information sifting. The information sifting effort has completed addition of the addition spectra creation (and deletion) capability and creation of reference library features.

Flexible Scintillating Optical Fiber Sensor for Determination of Liquid Level

Several sol-gel fibers doped with zinc sulfate were prepared during this reporting period. These fibers provide an indirect method for testing the coating procedure to be used with the light guiding fused silica capillary. The fibers were prepared using different chemical mixing ratios, and fluorescence was observed (with the naked eye) when the fibers were exposed to UV radiation. Although the fluorescence intensity was not optimal, successful doping of the sol-gel indicated the potential for coating the inside of the capillary tubing with the appropriate scintillating chemicals.

Further enhancement of the fluorescence signal as well as implementation of the sol-gel into the capillary will be carried out during the next reporting period.

Tank Leak Detection and Monitoring System

A special ringdown gas cell, adapted from a commercial ringdown product, was received this month. The gas cell is 43 cm long and cylindrical in shape. It has one gas inlet and two gas outlets which are welded onto the gas cell. The gas cell is sealed with two anti-reflection, near-IR coated windows at each end of the cell, capable of operating under different pressure conditions. The laser beam will be coupled into the cell through a section of optical fiber. There is no flexible mirror mount for the ringdown alignment in the gas cell. The ringdown alignment will be achieved by rotating and pressing the ball washes and retaining rings which contact the ringdown mirrors. This cell will be mounted in a portable, anti-vibration metal plate with a dimension of 61 by 41 cm. This gas cell together with the supporting plate is the major optical and mechanical part of the tank leak detection system. Once this part is aligned, the system will be rock-solid stable. Testing of the gas cell in terms of its mechanical stability and the thermo expansion effect has been on-going in this month.

Task 3

Disposition of Idaho HLW Calcine

Support of INEEL Calcine Disposition Project

We received calcine simulants (RSH-1 and Run 17). Safety procedures for handling of the material were discussed and implemented. We initiated compositional analysis of the simulants. There appears to be a solubility problem that causes the fluorine concentration to be measured at much lower values than expected.

Task 4

Support of SRS Salt Disposition and Other SRS Alternatives

On-line Analysis for Defense Waste Processing Facility

Laser induced breakdown spectroscopy - DWPF project. To obtain the calibration data for the EA glass, we have to prepare the glass batch with different Li and Fe ratios. The chemicals necessary for making simulated environmental assessment glass were ordered. A stock glass batch mixture was prepared based on the composition of the EA glass found in the WSRC report, except Fe₂O₃ and Li₂O. The different ratios of Fe₂O₃ and Li₂O were added to the stock mixture to make calibration pellets and glass. The calibration data obtained from the pellets is satisfactory. The precision and accuracy are both better than 5% for the lithium and iron ratio higher than 0.2 (in EA glass the ratio of lithium and iron is around 0.32). The attempts to make glass from the stock mixture were not very successful. The mixture in the furnace was too thick to pour into the crucible. Both the composition of the stock mixture and the furnace heating procedure were adjusted to make a glass which can be poured to the different crucibles. We will continue testing the glass-making process to make the desired glass samples for the calibration. The trip to SRS to discuss the various issues related to the DWPF project was postpone to March.

Task 5

HEPA Filter Performance Assurance

Regenerable HEPA Filter Performance Testing

During the month of February a smoke test was completed. The smoke particulate was produced using an acetylene torch operated with excess fuel. The smoke particulate was captured using the ELPI sampling equipment. The ELPI impactor stages were transported to the Scanning Electron Microscope (SEM) Laboratory on the Mississippi State University campus for analysis. The DIAL team concluded work on three papers for presentation at the 2004 Waste Management Conference.

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