DIAL's Research Highlights
Diagnostic Instrumentation & Analysis Laboratory
Support of Closure Sites
Fernald Silos Project Monitoring and Control Integration
Progress on this task will be reported at a later date.
Accelerating Phytoremediation by Monitoring Plant Status
During the month of August, we started building our temporary greenhouse. We also prepared and analyzed some of the samples from previous experiments on mercury phytoremediation.
Bio-availability and Speciation of Mercury in the Oak Ridge Ecosystem
During this month, the test bed for simulating the aquatic ecosystem was set up. The steel fence was built around the test bed. We reported our project progress to DOE officers and program leaders from the Oak Ridge site and Oak Ridge National Lab. At the same time, our preliminary mini-test bed experiment with river sediment from East Fork Poplar Creek of Oak Ridge continued. We also hired one Ph.D. graduate student for the project.
The revised manuscript on the mercury analytical study has been submitted to Water, Air and Soil Pollution. The manuscript on mercury bioavailability and speciation will be submitted to Science of Total Environment soon. We will start to design and conduct the incubation experiment on transformation and speciation of mercury species in Oak Ridge soils under various redox status and moisture regions.
Support of Hanford Single Shell Tank Waste Disposition
In-tank/At-tank Characterization for Closure of Hanford Tanks
On a visit to Hanford on August 18, we presented to our Hanford collaborators a report on our progress to date and discussed our proposed efforts for the next Cooperative Agreement year. Hanfords Cold Test Facility (CTF) was also toured in order to learn about the requirements for demonstrating our systems.
Stereovision. During August, a global matching algorithm was developed. The initial results are promising. This is important because global matching will reduce some requirements/constraints for the original images, and will also reduce some errors.
Laser-induced fluorescence-spectral imaging. During August, a 409-nm diode laser was borrowed from the CRDS group in order to investigate the feasibility of utilizing a diode laser instead of a Nd:YAG laser for laser-induced fluorescence excitation of uranyl compounds. Use of a diode laser would enable us to develop a smaller (and less expensive) prototype LIF-SI system that would be easier to deploy within the Hanford waste tanks. LIF spectra of several uranyl compounds were recorded using the diode laser and the laser power dependence of the LIF intensity was investigated. The diode laser has been returned to the CRDS group and we are utilizing a Nd:YAG laser-pumped tunable dye laser for our on-going investigations.
Microwave-induced plasma-cavity ringdown spectroscopy. Efforts this month yielded a significant advance in the detection of uranium with plasma-CRDS, utilizing the blue diode laser. Uranium ringdown signal has been observed for the first time using a diode laser. Several experimental parameters, including the plasma flow rates and powers as well as the triggering of the detection electronics, are being optimized.
Fiber optic sensors. During this month, we tested the efficiency of packing the liquid-core waveguide fiber with a black rubber tube for shielding stray light from entering the fiber and hence the photomultiplier tube (PMT). PMT readings with and without the package were compared under conventional laboratory conditions (illumination mercury lamps are on; no black curtain on laboratory windows). Without the package, the PMT reading was saturated. With the package, the PMT showed a reading of several million counts per second. This result indicates that the package blocked most of the stray light. However, more effort is still needed to improve the package design.
Fourier transform profilometry. During August, the various on-going FTP efforts continued. These on-going efforts included (1) modification of probe tower motor to incorporate encoders in order to be able to determine the probe position; (2) efforts to contact TVA to learn about conditions and schedule for testing at the Regenesys facility; and (3) study of FTP measurements of submerged targets. FTP image analysis software has been enhanced with dynamic region of interest (D-ROI) selection. With this additional capability, analysis result has been improved by avoiding the unwanted/noisy areas. Work continued with adding the line intensity profile in the FTP image acquisition software, which will allow the operator to have immediate feedback during optical adjustments, especially for the contrast of fringe lines that are projected onto the target area.
Process Chemistry and Operations Planning for Hanford Waste Alternatives
A trip was made to Hanford to discuss current and FY 06 work elements. The work in FY 06 will focus on upgrading the neural network and on the evaluation of the potential for cost savings and early HLW batch preparation for the WTP using sludge washing (caustic leaching). Current work scope discussions centered on interfacing the neural network with the Hanford H2 model. Plans are for site engineers to evaluate the initial data set and provide recommendations for streamlining the data needs. Additional items for network development were identified.
Equilibration of aluminum in 1 and 3-m NaOH continued. Samples were prepared in 5-m NaOH; however, it has been difficult to prevent initial crystallization of the gibbsite on the walls of the sample vials. Additional tuning for the preparation is in progress.
Comparison of the FIU phosphate concentration profile from their S-109 saturated salt cake dissolution experiment revealed different trends than were predicted by the ESP model. These differences were traced to changes made by OLI Systems Inc. in porting ESP from version 6.5 to 6.7. Upgrading the DIAL/MSU DBLSLTDB database to properly model the phosphate chemistry is in progress.
Flexible Scintillating Optical Fiber Sensor for Determination of Liquid Level
A 3-in. thick black acetal rod (12 in. in length) and a 3/8-in. thick black acetal sheet (12 x 24 in.) were received during this reporting period, as needed for fabrication of an appropriate housing for the PMT.
An initial housing will be fabricated and the PMT tested (with the housing) for improved shielding of stray light.
Disposition of Idaho HLW Calcine
Support of INEEL Calcine Disposition Project
The results of all the testing (compressive strength and TCLP) on the last of the hydroceramic-fine particle samples have been completed. That completes Phase 1 of our project.
The first formulations have been made up from the new matrix using the cement, fly ash, and slag have been completed and much of the testing done. All formulations and testing will be completed by the end of next month.
We have acquired a new mixer which allows us to make torque readings that will enable us to correlate mixing behavior with the viscosity of the mix. These observations will allow us to better design a mixer for next years pilot scale facility as well as for full-scale operations.
Support of SRS Salt Disposition and Other SRS Alternatives
Support for SRS Salt Disposition Alternatives
Literature information collection for plutonium and technetium is still ongoing. Strontium model calculations are currently being performed and will be compared to literature data to identify gaps in the model. Once these gaps are identified, strontium systems will be selected for solubility studies at 25 and 50°C. Potassium nitrate/sodium hydroxide solutions have been prepared and the solutions at 25°C are approaching equilibrium. Additional potassium nitrate solutions are being prepared for measurements over a longer time frame in order to monitor true equilibrium. Cesium nitrate/sodium hydroxide solutions will be prepared in September.
A sludge simulant composition has been sent from SRS and ESP modeling was performed on the experimental preparation. In the next step the procedure will be used and laboratory evaluation of the sludge will be carried out at various stages. The work will provide an opportunity to see how well ESP can model sludge chemistry. The sludge will then be combined with salt cakes made previously to examine the interaction of the material on salt dissolution.
On-line Analysis for Defense Waste Processing Facility
A multivariate calibration technique was tested with the pellet data recorded early. The test results show that the technique can effectively correct the matrix effect which is a serious problem in emission spectroscopy in some samples. The preliminary test shows that both the precision and accuracy are reduced to below 2% for most major and minor elements. More tests will be conducted for different types of samples. Work continues on evaluating different experimental configurations to achieve best reproducibility for the slurry sample. To avoid quick sedimentation of solution, we installed an L-shaped bar inside the slurry which is rotating and shaking the sample during the measurement. The motion of the L-shaped bar is controlled by an electric motor. The dependence of the LIBS on several laser repetition rates (1, 2, 5, 10 Hz) was investigated. At low repetition rates (1 or 2 Hz), the pulse-to-pulse difference of the LIBS signal was found much lower than with 5 Hz or 10 Hz (5 - 8 times lower). With an optimized experimental configuration, a percent RSD below 5% for slurry is possible.
Support of Production of High Waste Loading Glasses in the DWPF
Progress on this task will be reported at a later date.
HEPA Filter Performance Assurance
Regenerable HEPA Filter Performance Testing
During August, a series of test was initiated to study the effect of repeated loading and washing on regenerable filter media performance. Media donated from Porvair, Mott, and CeraMem will be evaluated. The testing entails loading the filter to approximately twice the initial differential pressure with RIC surrogate, then regenerating the filter via a wash with 5 mL each of a dilute nitric acid solution and distilled/deionized water. The load/wash steps will be repeated 20 times for each filter type, with three replicates for each filter type. Parameters examined to evaluate filter performance include: initial differential pressure as a function of the number of load/wash cycles and the filtering efficiency and mass loading rate as a function of differential pressure. At the onset of data collection, the large aerosol generator and a pneumatic spray nozzle was used to disperse the RIC surrogate, however, the time needed to load each filter to twice the initial differential pressure was unacceptable. Also, the spray nozzle was easily clogged with RIC surrogate, adding to the time needed to complete each run. In an effort to expedite data collection, a laskin nozzle aerosol generator was constructed that performs exceptionally well, providing suitable loading times, count mean diameter, and geometric standard deviation of the challenge aerosol. All data has been collected for the Porvair media.
A test plan has been developed to study the effect of media velocity on the performance of traditional glass fiber HEPA filters. Media velocities of 2, 4, 6, 8, and 10 ft/min will be studied, corresponding to volumetric flow rates of 125, 250, 375, 500, and 625 cfm, respectively. The media velocity tests are currently being set up.
Two abstracts were submitted to the Waste Management '06 Conference to be held in Tucson, Arizona, February 6 to March 2. The titles are: "Evaluation of Glass Fiber HEPA Filters as a Function of Media Velocity" and "Lifetime Testing of Sintered Metal and Ceramic Membrane Regenerable Filter Media".
Dr. Sandum Fernando, Assistant Professor in Agricultural and Biological Engineering, contacted DIAL about the possibility of measuring the droplet size produced from a capillary electrospray system. He suspected that his system was producing nano-sized droplets and his working fluids were glycerin, ethanol, and methanol. We were unable to measure the droplet size directly using the SMPS. It was suspected that the droplets were evaporating before reaching the detection region of the instrument. To this end, a 0.06% by weight KCl in methanol solution was used in the electrospray system. We were able to observe a significant aerosol count above background using this method. The data is currently being analyzed.
Inquiries may be addressed to:Dr. Roger King, Interim Director
205 Research Blvd.
Starkville, MS 39762-5932