DIAL's Research Highlights
Diagnostic Instrumentation & Analysis Laboratory
Support of Closure Sites
Fernald Silos Project Monitoring and Control Integration
Waste stabilization formulation development.
Formulation testing continued. During March, the primary goal of the grout testing was to test the grout formulations against the TCLP protocol. Six TCLP samples were prepared and allowed to cure for one week. Preliminary TCLP extract determinations were made for all samples. The six samples included a low waste loading, a high waste loading, a high salt concentration, and three different cement content samples. The TCLP protocol will be performed on the samples next month. In addition to TCLP samples, several samples were prepared in order to quantify the amount of free water that was present on a sample during a two-week curing cycle.
The following activities are planned for the upcoming months:
Accelerating Phytoremediation by Monitoring Plant Status
During the month of March, we have been analyzing samples and data from previous experiments. We have also been preparing and revising manuscripts for publication. One of our papers, "Phytotoxicity and Phytoaccumulation of Trivalent And Hexavalent Chromium In Brake Fern," has been accepted for publication in Environmental Toxicology and Chemistry.
Bio-availability and Speciation of Mercury in the Oak Ridge Ecosystem
The design team presented the first draft of the test bed design. We compared the cost of building such a test bed to a similar size aquarium and are now considering the alternate test bed plan. At the same time, we prepared soil/sediment samples from Oak Ridge, TN, for a preliminary experiment on the performance of the test bed. In addition, we finished all plant tissue sample digestion/preparations from the previous experiment on testing bio availability of mercury in Oak Ridge soils.
Future work will include:
Support of Hanford Single Shell Tank Waste Disposition
In-tank/At-tank Characterization for Closure of Hanford Tanks
Stereovision. During March, preliminary results obtained using the stereovision effort's new UNIX-based software indicate that the computational time was significantly reduced and the precision of determinations was improved. Our evaluation of the UNIX-based system will continue.
Laser-induced fluorescence-spectral imaging. During March, the LIF-SI effort continued our analysis of LIF spectra obtained with 532-nm excitation from a Nd:YAG laser. After replicating our results, we will utilize 355-nm Nd:YAG laser irradiation in order to determine which excitation wavelength is better.
Microwave-induced plasma-cavity ringdown spectroscopy. A NO2 monitor system is being developed using close-to-cavity enhanced spectroscopy with a compact blue diode laser source. Two different cavity configurations are being explored to determine the detection sensitivity of the system. The major efforts this month focused on improvement of the measurement accuracy of the system and determination of the absorption cross-section of NO2 at 409 nm under atmospheric conditions. One manuscript entitled "Ringdown Measurements of Mercury and its Hyperfine Structures at 254 nm in an Atmospheric Microwave Plasma Source: Spectral Interference and Analytical Performance" was written and submitted to the Journal of Analytical Atomic Spectrometry.
Fiber optic sensors. A new liquid-core waveguide, which is a quartz capillary coated with a thin layer of Teflon AF polymer on the inner surface, has been purchased this month. The liquid-core waveguide was filled with the CdSe/ZnS quantum dot solution. One end of this quantum dot-filled liquid-core was sealed by gluing a piece of reflective film on the end. An ordinary silica optical fiber was inserted into the distal end of the liquid core waveguide in order to guide light emitted by the quantum dots to a photodetector. This sensor will be evaluated to determine if it can efficiently detect gamma rays.
Fourier transform profilometry. During March, the Fourier transform profilometry (FTP) group's efforts to integrate the telescoping probe and the support tower with the base plate continued. For the elbow section housing the FTP optics, our efforts to reduce the weight of the elbow portion of the probe continued. Options currently under consideration are: 1) dual usage of a lamp for both grid pattern projection and utility illumination; and 2) replacement of the HID lamp with multiple high-intensity LEDs. Software development of the FTP probe motion control also continued. We have begun investigating the possibility of utilizing two large, empty storage tanks (59-ft and 54-ft diameters and 32-ft height) at TVA's Regenesys facility in Columbus, MS, for testing of our probe-based imaging systems prior to demonstration at Hanford's Cold Test Facility. Optimization via acquiring images of simulated targets continued using the finalized elbow section of the FTP probe. Analysis of the images will follow. The spectrum of cases of possible target measurements that may be encountered in a Hanford tank has been presented. More measurement scenarios will be simulated. Our study of FTP measurements of targets submerged beneath liquids has been initiated. For this initial study, clear tap water was utilized as the liquid. We have carried out these simulation experiments with targets of various dimensions and with different levels of water depth. A preliminary analysis of the measurement data indicated that, with the current FTP system, the shapes of the targets can be reconstructed. However, the accuracy of reconstruction is not satisfactory due to distortion introduced by the refraction of light in water. Further study on approaches to correct the distortion is under way.
Process Chemistry and Operations Planning for Hanford Waste Alternatives
Results from the FIU tall column modeling studies along with recent solubility studies on the Al-NO3 and Al-PO4 systems were presented at the SRS/HNF Technical Exchange in late March. Additional solubility studies on the aluminum system to extend the range of conditions are under development.
Much work has been accomplished in collating data needed for the neural network initiative for the HTWOS model. The initial data package is expected to contain solubilities and physical parameters for Al, NO2, NO3, OH, and Na. Discussions are in progress with the HNF customers for specifying the actual package configuration. It is anticipated that access to the NeuronLine analyzer will occur within the next quarter.
Work on the DBLSLTDB database continues. Efforts are underway to evaluate additional regression fits that would be needed to port the database to ESP version 6.7. Some improvements in the ESP database have been noted between versions 6.5 and 6.7. It is anticipated that some interaction parameters will change; however, initial evaluation of pure component carbonate and nitrite-hydroxide indicate that specific systems contained in DBLSLTDB can be used as is.
Flexible Scintillating Optical Fiber Sensor for Determination of Liquid Level
During this reporting period, the emission spectra of CdSe/ZnS quantum dot doped PMDS and PMMA were compared to the spectrum of the same quantum dots in a toluene solution. The peak emission wavelengths of the two polymeric materials were very similar to that of the solution based measurement. This similarity seems to indicate preservation of the original quantum dot structure during the doping process, making these materials ideal for sensing high energy particles.
Future efforts will be focused toward testing the response of the quantum dot doped materials to high energy particles.
Disposition of Idaho HLW Calcine
Support of INEEL Calcine Disposition Project
Work on this task will be reported at a later date.
Support of SRS Salt Disposition and Other SRS Alternatives
Support for SRS Salt Disposition Alternatives
Modeling of the 37H SRS simulant DASR experiment encompassing the standard flowsheet and an adjusted flowsheet was completed and experimental data were compared to each. The adjusted model more closely resembled the experimental nitrate, carbonate and nitrite ion profiles. A description of these flow sheets and results from this experiment and all experiments for Tank 38H simulant were presented at the Salt Technology Exchange held at Savannah River during the week of March 21, 2005.
Work on heel dissolution processes using the remaining cancrinite layer from the 37H DASR experiment and literature searches for potassium and cesium solubility studies have begun.
On-line Analysis for Defense Waste Processing Facility
Since the problem with the Echelle spectrometer has not been solved, we had to set up an independent LIBS system to continue the LIBS slurry measurement. Unlike the broadband Echelle spectrometer, only a 20-nm spectral region can be simultaneously detected in this detection system. In order to cover more elements, every experiment must be repeated at several different spectral regions. The slurry sampling system was set up in horizontal position, and a 1-inch inner diameter venturi was attached in the sampling system. Our previous study has shown that this setup for the sampling system can produce the most reproducible flow. The optimum experimental parameters for this system were determined by comparing the data recorded at different laser energy, gate delay, gate width, and focusing condition. To obtain calibration data for slurry, we are now testing the method that spikes the slurry with different elements.
Support of Production of High Waste Loading Glasses in the DWPF
Video camera observations are continuing for melting glass from the 155% and 185% slurries and powders. Pellets were made from each of the dried slurries so that the two compositions could be compared side by side. It was observed that the 185% pellet melted before the 155% pellet.
The presentation for the American Ceramic Society in April has been prepared and is ready for the meeting.
HEPA Filter Performance Assurance
Regenerable HEPA Filter Performance Testing
During March, Mott sintered metal fiber filters and Mott powdered metal fiber filters were challenged with RIC waste surrogate. Testing was performed at standard operating conditions for the test stand and particle generator. These filters were loaded and washed three times each. Scanning electron microscope (SEM) imaging was done for each of these filters.
Future testing includes challenging additional filters with the RIC waste surrogate as well as preparation for media velocity testing with glass fiber HEPA filters.
Inquiries may be addressed to:Dr. John Plodinec, Director
205 Research Blvd.
Starkville, MS 39762-5932