November 2004 |
|
DIAL's Research Highlights | |
Diagnostic Instrumentation & Analysis Laboratory
| |
Task 1 |
Support of Closure Sites Fernald Silos Project Monitoring and Control Integration Waste stabilization formulation development. Formulation testing continued. During November, the primary goal of the grout testing was to determine the effect of high salt concentrations on the final grout product. Samples were prepared at three different salt concentrations. All three salt levels resulted in a thinner grout mix than was observed in similar batch formulations with low salt concentrations. However, the grout product passed the free water criteria at all three salt concentrations. The grout stabilization interim report was prepared and sent to Fernald management for review. The following activities are planned for the upcoming months:
Accelerating Phytoremediation by Monitoring Plant Status We continued a phytoremediation experiment of mercury with brake fern; the experiment was started in October and will be finished in December. Mercury contaminated soil used in the current study was from a previous experiment; soil from each treatment group was mixed and sampled before being used again. Bio-availability and Speciation of Mercury in the Oak Ridge Ecosystem We presented some of our results on bio-availability and phytoremediation studies of mercury contaminants in a DOE workshop held in Oak Ridge, TN. |
Task 2 |
Support of Hanford Single Shell Tank Waste Disposition In-tank/At-tank Characterization for Closure of Hanford Tanks Stereovision. The stereovision effort acquired images at selected separations and angles between the cameras. These investigations are part of our on-going efforts to optimize the stereovision system for conditions appropriate to the Hanford waste tanks. Laser-induced fluorescence-spectral imaging. The LIF-SI effort continued working on optimizing experimental conditions for recording LIF spectra. The new graduate student associated with this effort has completed radiation safety training and has now begun experimental work. Microwave-induced plasma-cavity ringdown spectroscopy. Over the course of this last month, we have been examining the performance of the new blue diode laser system.Efforts include wavelength calibration using an ultraviolet wavemeter, testing wavelength modulation, and examination of the laser beam quality. Utilization of this diode, with an optimum output over the 406 to 409.4-nm wavelength region, will allow exploration of the 409.0135-nm line of uranium. A new ringdown cavity, implementing this laser system and the corresponding optics, is being constructed and tested for uranium elemental and isotopic measurements. A slight obstacle was encountered and diligent work has been performed to circumvent this difficulty: the intensity of the new diode laser at the wavelength of choice is such that the transmission of the laser light through the ringdown mirrors is unacceptably high. Neutral density filters placed between the laser and the front ringdown mirror have been utilized to help minimize this transmission. Three manuscripts about ringdown measurements of elemental mercury under different experimental conditions are being written for publication. Fiber optic sensors. We located a commercial source providing CdSe/ZnS core-shell quantum dots. A small quantity (20 mg) of the CdSe/ZnS core-shell quantum dots has been ordered. Quantum dot materials are highly fluorescent and have been used to detect alpha particles. Fourier transform profilometry. The FTP probe development effort focused on design of the probe support tower and selection of a motion controller for the servo-motors. A 2.5 ft-high, full-scale mock-up of the tower was fabricated to verify the feasibility and difficulty of joining the tubular elements of the structure. A prototype 6-ft tower section utilizing stainless steel tubing and welded joints will be constructed after consultation with the welder regarding proposed joint details. A four-axis servo motion controller was selected to manage the probe manipulation. It will be remotely mounted near the base of the probe and will accept positioning and movement commands via either Ethernet or RS-232 communication links to the computer used for image processing. The ability to remotely locate processing of position feedback and the motor drive power switching in a small form factor will allow for a minimal amount of control wiring that must be routed back to the main computer. Efforts to optimize the fringe pattern projection system for conditions appropriate to the Hanford waste tanks continued. A variety of targets of different sizes were fabricated in order to more accurately assess the precision of the FTP volumetric determinations as a function of distance. Process Chemistry and Operations Planning for Hanford Waste Alternatives Studies on the quantification of aluminum in matrices of high sodium concentrations continued. A number of options for increasing the accuracy of the aluminum measurement were evaluated including collecting the ICP emission in the radial mode, use of an internal Sc standard, and an evaluation of the flow conditions to the torch. Use of the internal standard with operation in the radial mode and a reduced flow rate to the torch resulted in errors of less that 2% for sodium concentrations from 0 to 500 ppm. These results should be contrasted to those determined with the standard axial mode configuration without the use of an internal standard where errors of up to 16% were found. Equilibrium has been attained for most of the aluminum solutions for the solubility studies. Filtration/centrifugation had been completed for three series of the Al-PO4 system at 25°C and for two series of the Al-NO3 system, again at 25°C. Sample dilution is in progress followed by ICP and IC analysis. Considerable efforts have been expended in the modeling of the pilot-scale salt cake dissolution experiments at FIU. Dividing the column into a number of stacked sections has been shown to increase the computational overhead and results analysis time considerably. Work continues in analyzing the model results and comparing the results to the experimental data obtained. Flexible Scintillating Optical Fiber Sensor for Determination of Liquid Level A commercial provider of quantum dots was selected during this reporting period and the Cd/Se/ZnS core-shell quantum dots (20 mg) were ordered from the respective company. In addition, laboratory preparation for synthesis of the sensing materials was initiated. Efforts to produce quantum dot doped sol gel glasses is scheduled to begin at the beginning of the 2005 calendar year.
|
Task 3 |
Disposition of Idaho HLW Calcine Support of INEEL Calcine Disposition Project The analysis of the scoping runs was completed, and ANOVA analysis was performed on the data. The results of the compressive strength and leachate tests will be discussed in the next quarterly report. The ANOVA analysis was performed using the MINITAB statistical analysis program. The poor confidence level in some of the results could be due to several factors. The simplest explanation is that the samples were not completely homogenized during mixing. This is unlikely however, because the samples were mixed using an electric mixer for long periods of time. The most likely explanation is that the poor confidence is due to inherent variability of the samples themselves. With a limited sample size of three, a large variability can be expected.
|
Task 4 |
Support of SRS Salt Disposition and Other SRS Alternatives Support for SRS Salt Disposition Alternatives The drain, add, sit, and remove experiment for the simulant to SRS tank 37H was completed. This experiment lasted approximately six weeks as compared to the two week period for the experiment on the 41H simulant. The longer time is attributed to the formation of a low permeability layer within the column as dissolution proceeded. ESP modeling of the experiment indicated that cancrinite would be expected to form during the simulant preparation. In the case of the 37H composition, the molar aluminum-to-silicon ratio is close to a value of one, and sodium and carbonate are in excess. Consequently, it was initially believed that cancrinite had been produced, and that the layer formed by re-distribution of the aluminosilicate within the column as opposed to an on-going chemical reaction such as the precipitation of gibbsite from Al(OH)4 - as water as added. The later effect was earlier observed for a Hanford waste simulant. The layer material was isolated and additional preparations of the key chemical constituents (NaOH, NaAlO2 , H2O and Na2SiO2·5H2O, with and without Na2CO3·1H2O), were made. With the addition of the carbonate it was expected that cancrinite would form, without the carbonate the expected product was expected to be hydroxysodalite. Analysis of these products and the associated layer material are in progress. Powder diffraction patterns for the material were identical and were not consistent with reference patterns for cancrinite or for sodalite. ICP analysis of the solids composition is in progress as well as further interpretation of the XRD patterns. On-line Analysis for Defense Waste Processing Facility A sludge sampling system was designed and fabricated based on the physical parameters of the DWPF slurry. Since we only have limited DWPF simulant, we will have to test this sampling system with the RIC slurry. The system will be tested under different operating conditions, and it will be modified based on the initial test results. We will request DWPF staffs to send us the appropriate amount of simulant for the later test. Work also concentrated on improving the measurement accuracy. Due to the characteristic of the emission line, every analyte line has its own optimum excitation condition. To improve the measurement accuracy for multi-element measurement, the measurement should be made under an experimental condition that produces near optimum excitation condition for most elements. However, the optimum experimental parameters for each analyte line will also change with the elemental concentration. We are performing an extended experimental study to find the experimental condition that can be used for various matrixes. Support of Production of High Waste Loading Glasses in the DWPF Thermal analysis using differential scanning calorimetry (DSC) and differential thermal and thermogravimetric analysis (DTA/TGA) has been done on the 155 and 185 slurries. Other than relatively low temperature reactions involving water and carbonates, very little information was gained regarding the comparative reactivity of the two materials. Slumping experiments are being designed and will be run during the next reporting period. |
Task 5 |
HEPA Filter Performance Assurance Regenerable HEPA Filter Performance Testing Additional testing was performed on the particle generator. First, while using a 30% potassium chloride (KCl) solution, the operating parameters of the particle generator were varied to determine the effect on mass loading rate and particle size distribution. The operating parameters varied were air flow rate through the nozzle, the pump flow rate (rpm), and the sheath air flow rate. Second, the operating conditions were kept constant and the concentrations of the solutions fed to the nozzle were varied. The types of solutions used were potassium chloride (KCl), table salt (NaCl), table sugar, and ferrous sulfate (FeSO4). The concentrations used were 0.3, 3 and 30% for each solution. The data from all these tests is currently being analyzed. |
Inquiries may be addressed to: Dr. John Plodinec, Director205 Research Blvd. Starkville, MS 39762-5932 |
Phone: 662-325-2105 FAX: 662-325-8465 Email: dial@dial.msstate.edu |