DIAL's Research Highlights
Diagnostic Instrumentation & Analysis Laboratory
Support of Closure Sites
Fernald Silos Project Monitoring and Control Integration
Waste formulation development has been suspended until new K-65 material can be supplied to the DIAL facility. Brian Kauffman and Chris Williams traveled to the Fernald Closure Site to discuss outstanding technical issues with batch formulations, laboratory testing and waste disposal. Paul Pettit requested that the DIAL team evaluate a means of mixing a grout sample continuously for up to or beyond 24 hours. The problem lies in the fact that the grout samples are shear thinning materials and the bulk of the sample volume may not be mixed due to localized shear thinning phenomena. DIAL will evaluate different mixing configurations. The following activities are planned for the upcoming months:
Accelerating Phytoremediation by Monitoring Plant Status
During the month of September, we finished building our greenhouse. We have also been analyzing samples and data from previous experiments on mercury phytoremediation. Some of our results were presented at the Oak Ridge Mercury Workshop, which was hosted by the DOE Oak Ridge Site in September.
Bio-availability and Speciation of Mercury in the Oak Ridge Ecosystem
During this month, we have started a series of new experiments on dynamics and kinetic rates of mercury transformation and bioavailability in an Oak Ridge soil contaminated with mercury nitrate, chloride, sulfide, and elemental mercury under various moisture regimes. Three moisture regimes include saturated paste, field capacity, and air-dry moisture regimes. The contaminated soils were incubated at room temperature. Soil samples were, or will be, taken in one day, ten days, one month, two months, and six months. At the same time, we continue our preliminary mini-test bed experiment with river sediment from East Fork Poplar Creek of Oak Ridge continues. Also, this month, we gave a presentation on mercury bioavailability and speciation in Oak Ridge soil at the 2nd US DOE Oak Ridge Mercury Workshop at Oak Ridge, TN.
A manuscript on mercury analytical study has been accepted by Water, Air and Soil Pollution. A second manuscript on mercury bioavailability and speciation in an Oak Ridge soil has been submitted to Science of Total Environment.
We will continue conducting the incubation experiment on transformation and speciation of mercury species in Oak Ridge soils under various redox status and moisture regions. We will plan to go to Oak Ridge for soil sampling.
Support of Hanford Single Shell Tank Waste Disposition
In-tank/At-tank Characterization for Closure of Hanford Tanks
Stereovision. During September, the stereovision effort developed a global match (i.e. non-epipolar) algorithm. Using this algorithm, good results have been obtained with various objects. It has also been applied to investigate smaller objects (in cm-mm range) as part of the effort for characterization of the aluminum liner pit corrosion in the Oak Ridge Research Reactor and for support of Task 4.3. A decision has been made to incorporate digital zoom capability and to utilize a camera lens with higher zoom power (in order to take "close-up" images of the object and hence obtain a better disparity map). Consequently, the stereovision system is being upgraded with new image grabbing board cameras with higher zoom capability. In addition, progress on stereovision and Fourier transform profilometry for Hanford tank characterization was presented at the 10th International Conference on Environmental Remediation and Radioactive Waste Management (ICEM05) in Glasgow, Scotland during September.
Laser-induced fluorescence-spectral imaging. During September, a Nd:YAG laser-pumped tunable dye laser was used to excite simple uranyl compounds at wavelengths near 425 nm. The resulting laser-induced fluorescence (LIF) spectra were recorded. These experiments are being performed to select the excitation wavelength that will be utilized for future work.
Microwave-induced plasma-cavity ringdown spectroscopy. In addition to further optimization of the experimental parameters for the plasma, efforts this month included an in-depth analysis of the mathematical approach to data processing and the determination of the vertical and lateral positions which were most conducive to uranium observation. Utilizing the current experimental set-up, uranium has been readily observed at various concentrations. Improvement in the signal-to-noise ratio, calibration of the uranium signal, and optimization of the electronic controls for the new parameters are to follow.
Fiber optic sensors. During this month, the fiber optic sensor effort focused on shielding the photomultiplier tube (PMT) from stray light and on reducing PMT noise level during scintillation detection. A search has been performed to find a material and design a package to insulate the PMT from stray light. Two methods were considered. The first method is packing the PMT with a black Acetal sheet. The second method is inserting the PMT into a black cylinder made from black Acetal and sealing the cylinder with a cap made from the same material. The materials have been purchased and a work order for the cylinder and cap has been sent to DIAL's machine shop.
Fourier transform profilometry. Work on the FTP probe support tower design continued and concentrated on finalizing the design of the cable management system, particularly its role during system setup on top of the tank's riser. The measurement scheme developed for system testing at the local TVA Regenesys tank facility is based upon the riser being in the center of the tank; improvement of the measurement plan for off-center risers was initiated. Modification of the probe tower motor to incorporate the encoder continued, as did our study of FTP measurements for submerged targets. Work on FTP image acquisition software improvement was completed: a line intensity profile has been added to the FTP image acquisition software. This allows the operator to have immediate feedback during optical adjustments, especially for optimizing the contrast of the fringe lines that are projected onto the target area.
Process Chemistry and Operations Planning for Hanford Waste Alternatives
The preparation of solutions of aluminum in caustic with added sodium nitrate continued. Work this month focused on 7-m caustic; at this point all of the solutions for the aluminum solubility studies have been made. Based on previous studies, an equilibration time matrix is being developed.
Work continued on improving the statistical results for the neural network training set. Means for evaluating the training set using existing data and previous facility data associated with evaporation experiments is under evaluation.
Revised regression fits for phosphate in caustic and for sulfate in nitrate solutions were completed. These results complete the fitting necessary to port the DIAL DBLSLTDB database from ESP version 6.5 to 6.7. Distribution of the revised database to engineers at Hanford and at Savannah River are planned for October.
Flexible Scintillating Optical Fiber Sensor for Determination of Liquid Level
Black Acetal sheets and Acetal rods have been purchased from Small Parts, Inc. The black materials will be used for shielding the PMT in order to prevent environmental stray light from entering during weak scintillating signal detection. A work order has been submitted to DIAL's machine shop to make a cylinder with a sealing cap for housing the PMT.
Disposition of Idaho HLW Calcine
Support of the ICP-SP3 Calcine Disposition Project
The Phase II Test Results were issued and updated to include all analytical data to date (all TCLP values from triplicate runs and the PCT).
Due to some wide variability in the TCLP values, we are concerned that the mixing process is not adequate. We are therefore evaluating alternatives for mixing impellers. Philadelphia Mixer advertises a mixing impeller designed for shear thinning materials. It is called a CF series impeller and has standard blades with an additional blade with the opposite pitch direction added to the tip in order to facilitate moving the material counter-directionally at the sides of the vessel. DIAL will look into obtaining an impeller with similar attributes.
Support of SRS Salt Disposition and Other SRS Alternatives
Support for SRS Salt Disposition Alternatives
Potassium nitrate/sodium hydroxide solutions have been prepared for measurements over a longer time frame in order to monitor true equilibrium. In addition, two separate cesium nitrate/sodium hydroxide solutions have been made for 25 and 50°C studies. One solution will remain untouched and the other will have weekly sampling for analysis. Once equilibrium is established, the untouched solution will be filtered and the data obtained used for regressions.
The sludge simulant composition sent from SRS is currently being prepared. The preliminary experimental results through phase four demonstrate good correlation to model results. Due to the small particle size of the solids, the inhibited wash cycles must be centrifuged before separations. Additions of the final solids, analysis of the final sludge simulant, and inclusion in SRS 41H simulant for a DASR experiment will be performed during October.
On-line Analysis for Defense Waste Processing Facility
Dr. Singh and Ms Yueh visited SRNL on September 29 to present the progress of the project and also to discuss the future work plans. SRNL recently provided sludge samples for LIBS experiments. But their main interest is to use LIBS on the melter feed; therefore, we need to make simulated melter feed at DIAL. To make melter feed from the sludge batch, we will follow a procedure to add acid, heat the sample and then add frit to the sludge batch. SRS agrees to provide us different frit samples and the formulae so we can simulate the melter feed. We have started initial study on the SRNL sludge batch (SB). This sample has high Fe and Al concentrations, and the sample is thicker and easier to handle than the RIC sample we used in previous tests. The sample in a small beaker was placed on a rotation platform and a fan was used to remove the aerosols generated by laser-induced plasma. Data was collected at different laser repetition rates and at a long duration time to investigate the signal reproducibility for this sample. We added water to the SB to investigate the correlation of the sensitivity of LIBS signal decay. The frit powder with the 5.0% Li2O concentration was blended with the SB in various proportions to yield a mixture with 0.0 - 1.15% Li2O content. The initial test shows that the intensity Li line linearly increases with the concentration of Li in the slurry.
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
Last month, a test plan was 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. Final preparations for this study were completed during the month of September. Communication between the particle measuring system laser particle counter and a notebook computer was established and we were able to demonstrate that the PMS unit can generate aerosol particle size distribution downstream of a HEPA filter. A second blower was added to the HEPA filter test stand to generate the volumetric flow rates needed for the study. Also, the test stand was taken apart and cleaned.
Inquiries may be addressed to:Dr. Roger King, Interim Director
205 Research Blvd.
Starkville, MS 39762-5932