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 October, we have been analyzing samples and data from previous experiments on mercury phytoremediation. During this month, one of our paper, "Monitoring the effects of arsenic and chromium accumulation in Chinese brake fern (pteris vittata)", has been accepted for publication in International Journal of Remote Sensing.
Bio-availability and Speciation of Mercury in the Oak Ridge Ecosystem
During this month, we have continued in conducting the experiment 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 three moisture regimes (saturated paste, field capacity, and air-dry). We have conducted sequential selective dissolution study of soils after incubation of one day, ten days, and a month. One thousand of samples have been generated for analyses. At the same time, we have arranged sampling of the field mercury contaminated samples from Oak Ridge, TN.
We will continue in conducting the incubation experiment on transformation and speciation of mercury species in Oak Ridge soils under various redox status and moisture regions. Hopefully we will get the Oak Ridge mercury contaminated soil samples next month.
Support of Hanford Single Shell Tank Waste Disposition
In-tank/At-tank Characterization for Closure of Hanford Tanks
Stereovision. During October, the stereovision effort has significantly upgraded system capabilities by purchasing new cameras and a new image acquisition board. The new cameras are capable of x25 zoom (compared with the x10 zoom of the previous cameras). The new imaging acquisition board enables us to utilize digital zooming capability. Composition of a paper for publication in a refereed scientific journal has begun.
Laser-induced fluorescence-spectral imaging. During October, experiments have begun on simple uranyl compounds mixed at a variety of concentrations with other solid materials (in this case, sand). Sand was chosen because it does not fluoresce at these excitation wavelengths; furthermore, a uranium-sand mixture is not considered a mixed hazardous waste for waste disposal purposes. These experiments will enable to determine the limits of detection for LIF spectral imaging detection of uranyl compounds in mixtures.
Microwave-induced plasma-cavity ringdown spectroscopy. Due to the extensive use of the plasma-cavity ringdown system as well as the fluctuating temperatures arising from the changing seasons, several experimental parameters had to be modified. The blue diode has proven to be temperature sensitive, resulting in a noticeable drift in the laser wavelength. Therefore, the laser wavelength needs to be constantly monitored and the corresponding electronics have to be adjusted throughout the experiments. Once this artifact was taken into consideration, realistic baseline stabilities were once again obtained. Further optimization of the electronic controls to the new parameters, which will allow for better baseline stabilities and, in turn, better detection limits, as well as calibration of the uranium signal are to follow.
Fiber optic sensors. During this month, the package for shielding stray light from entering the photomultiplier tube (PMT) has been designed and fabricated. The package for the PMT is a cylindrical tube drilled from a black Acetal rod. A cap with a connection channel was fabricated to seal the cylinder tube. An optical fiber will be pushed through the connection channel and connected to the PMT with a SMA fiber optic connector. The black tube for shielding the optical fiber will be connected to the connection channel on the cap. The ability to shield the PMT from stray light is important for obtaining low limits of detection.
Fourier transform profilometry. During October, work on design and fabrication of the FTP probe support tower continued and concentrated on finalizing the design of the cable management system and the base plate, particularly their role during system setup on top of tank's riser. Our study of FTP measurements of submerged targets continued. The FTP analysis software has been improved by resolving the problem of zero-value pixels along borders of a reconstructed height image. The FTP acquisition/analysis software has been modified by utilizing a lossless image compression format, portable network graphics (PNG), as the default format for saving images.
Process Chemistry and Operations Planning for Hanford Waste Alternatives
All of the aluminum solutions in sodium hydroxide have been prepared and are equilibrating. Analysis of the solutions is being performed as a function of time such that thermodynamic equilibrium can be confirmed.
Efforts continued on the re-packaging of the DIAL/MSU double salt database for ESP version 6.7. Additional fits for carbonate in nitrite and in nitrate were performed. It is anticipated that the next release of the database will be in early November. Papers were presented at the 14th Symposium on Separation Science and Technology for Energy Applications held in Gatlinburg, TN regarding the development of the database and previous calculations performed on the fractional crystallization of Hanford salt wastes.
Flexible Scintillating Optical Fiber Sensor for Determination of Liquid Level
The package for shielding stray light from entering the PMT has been designed and fabricated. The package for the PMT is a cylinder tube drilled from a black Acetal rod. A cap with a connection channel was fabricated to seal the cylinder tube. An optical fiber will be pushed through the connection channel and connected to the PMT with an SMA connector. The black tube for shielding the optical fiber will be connected to the connection channel on the cap.
A graduate student was assigned to work on the computer program for the PMT. The graduate student is in the process of learning the PMT principle and the working mechanism of the PMT.
Disposition of Idaho HLW Calcine
Support of ICP-SP3 Calcine Disposition Project
A draft of the annual report was issued to INL and their comments received. The document will be completed in early November.
A new set of formulations based around the 1:0.5:0.5 (cement:slag:flyash) composition has been fabricated and testing will be completed in November. A number of formulations were retested for TCLP because of what was thought to be a wide spread in previous results for some values. There continues to be variability, but we believe this to be inherent with the tests. We continue to keep a close eye on these tests. We are also continuing to examine alternatives for mixing impellers. As we scale up from the laboratory to pilot scale, we are examining every factor that may influence the mixing of the batch.
Support of SRS Salt Disposition and Other SRS Alternatives
Support for SRS Salt Disposition Alternatives
Potassium nitrate/sodium hydroxide and cesium nitrate/sodium hydroxide solutions have reached equilibrium for all samples prepared at 25°C. No solids have formed in the potassium systems at 50°C so new solutions have been prepared. We are currently awaiting analytical results from the 25°C systems for regressions.
The SRS sludge simulant preparation has been completed and samples have been submitted for final solids wt% and soluble solids wt%. Once results are received and compared to the simulant report, a DASR experiment will be conducted using the SRS 38H simulant prepared earlier. After discussion with the site, the amount of sludge to be added will be approximately three percent by weight.
A presentation was made at the 14th Symposium on Separation Science and Technology for Energy Applications held in Gatlinburg, TN on work accomplished for the 38H and 37H SRS simulant experiments. In addition, a paper on this work was submitted for publication in Separation Science and Technology.
On-line Analysis for Defense Waste Processing Facility
The main interest of the DWPF is to use LIBS on melter feed product. To evaluate LIBS on melter feed product, we have to make our own simulated melter feed from the sludge batch provided by the DWPF. The process of making simulated melter feed involves adding acid, reducing the water contents in the sample, and finally adding the proper amount of frit to the sludge batch. Currently, we are studying the process of making simulated melter feed in our laboratory. The LIBS data were also recorded from the sludge products obtained from each chemical process in making simulated melter feed (i.e., raw sludge batch, acidified sludge product, and simulated meter feed) to characterize these sludge products. Various experimental configurations are also being evaluated to find the most reliable configuration for all these sludge products.
Support of Production of High Waste Loading Glasses in the DWPF
A series of experiments has been set up to examine the evolution of interactions between frits 200 and 320 and the SRAT Case 7d waste simulant. The experiments will be run over a temperature range of 600°C to 800°C for times of 15, 30 and 60 minutes. The products of these experiments will be examined by optical microscopy and differential scanning calorimetry (DSC). There may also be an opportunity to examine them with x-ray diffraction (XRD).
HEPA Filter Performance Assurance
Regenerable HEPA Filter Performance Testing
The APS diluter was calibrated for 20:1 and 100:1 dilution ratios. A HEPA filter was placed in the test stand and the differential pressure drop across the filter and static pressure in the test stand was recorded as a function of volumetric flow in the range of 125-487 SCFM. This was done for two filters. The particle measuring system micro laser particle counter was used to measure downstream particle size distributions while no aerosol was being generated. This was done to observe the number and PSD of particle coming off the filter at various flow rates. The PMS MLPC was also used to measure the number and PSD upstream of the filter while no aerosol was being generated. This task was performed to ensure cleanliness of the air being drawn into the test stand. Media velocity testing at 250 SCFM (MV = 4 ft/min) was completed. Testing at 6 ft/min. was started, but not finished due to a fuse blowing in the large screw compressor. Media velocity testing will resume at this point in November.
Inquiries may be addressed to:Dr. Roger King, Interim Director
205 Research Blvd.
Starkville, MS 39762-5932