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 July, the primary goal was to continue expansion of the formulation testing using ADVACAST 530, a viscosity modifier, in conjunction with blast furnace slag. It has been demonstrated that during the processing phase, the non-homogeneity of the K-65 material creates significant difficulties in handling both the waste slurry and the grout product. ADVACAST 530 is a super plasticizer intended to reduce the viscosity of the final grout mixture without increasing the amount of bleed water present. However, preliminary testing has proven that the use of ADVACAST 530 does in fact increase the amount of bleed water for a given formulation. The testing also demonstrated that the amount of ADVACAST 530 required to create a self-pouring, self-leveling mix was three to five times the doping level indicated by the manufacturer.
The use of blast furnace slag in conjunction with the ADVACAST 530 proved to reduce the presence of bleed water on the grout samples. Samples were prepared with 10-wt percent and 20-wt percent slag. The slag replaced an equal amount of fly ash from the formulation. The 20% slag samples had acceptable mix and flow properties in addition to a lack of free water at 120 hours.
Meetings and workshops. Drs. Roger King and Charles Waggoner met with representatives from the Fernald management team in order to discuss the technical assistance needs of the Fernald Site for the next fiscal year. Also in attendance was Phil McGinnis, from the Oak Ridge National Laboratory. A follow-up meeting was scheduled to finalize the FY 2006 DIAL Scope of Work. This meeting will be held at DIAL on August 15, 2005.
Planned activities. The following activities are planned for the upcoming months:
Accelerating Phytoremediation by Monitoring Plant Status
During the month of July, we completed an experiment on mercury phytoremediation; the experiment was started in May. Samples of plant shoots, roots and soil were collected and prepared for chemical analysis.
Bio-availability and Speciation of Mercury in the Oak Ridge Ecosystem
During this month, the steel frame for one manufacturer-made 8 x 4 x 4-ft acrylic aquarium tank was made by our machine shop. A preliminary mini-test bed experiment with river sediment from East Fork Poplar Creek of Oak Ridge continues. Sediment was treated with HgCl2 at 100 mg/kg. At the same time, we are continuing to study the changes in bio availability of mercury species in contaminated soils with planting.
We will revise the manuscript on mercury bio availability and speciation. The second manuscript on mercury analytical study will be revised as well. We will continue the preliminary experiments on a small size test bed.
Support of Hanford Single Shell Tank Waste Disposition
In-tank/At-tank Characterization for Closure of Hanford Tanks
In lieu of the conference call with our Hanford collaborators previously scheduled for Wednesday, July 27 in order to discuss our progress and plans for the next Cooperative Agreement year, there will be a visit to Hanford on Thursday, August 18.
Stereovision. During July, the stereovision effort recorded reference images as a function of distance using selected magnification settings in order to obtain estimates of our current volume determination uncertainty; these efforts are on-going.
Laser-induced fluorescence-spectral imaging. During July, laser-induced fluorescence-spectral images of laser excited simple uranyl compounds were recorded using narrow-bandpass filters in order to monitor the fluorescence at a wavelength different from the laser excitation wavelength. A comparison between two different camera systems was begun in order to select a camera system for deployment. According to the literature, uranyl compounds typically have higher absorption coefficients in the 400 to 450-nm spectral region than they do at either 355 or 532 nm. Therefore, we have begun an investigation of the fluorescence from simple uranyl compounds excited in the 400 to 450-nm region. This investigation will be performed with a tunable dye laser or, if one can be borrowed from the CRDS group, a 409-nm diode laser.
Microwave-induced plasma-cavity ringdown spectroscopy. The charge-coupled device (CCD) detector of the plasma system has been repaired and re-installed in the plasma-CRDS system. The plasma system, including a diode laser, is being optimized for uranium measurement.
Fiber optic sensors. This month we tested the efficiency of packing the liquid core waveguide fiber within a black rubber tube in order to shield stray light from entering the fiber and the photomultiplier tube (PMT). The PMT readings with and without the shield were compared under conventional laboratory conditions (illumination by mercury lamps, no black curtain on laboratory windows). Without the black tube shield, the PMT was saturated. With the protective shield, the PMT has a reading of several million counts-per-second. This result indicates that the black tube blocks out most of the stray light. However, more effort is still needed to improve the shield design.
Fourier transform profilometry. During July, the FTP effort continued modification of the probe tower motor in order to incorporate an encoder, which will enable us to infer position. Our efforts to contact TVA to learn about conditions and schedule for testing at their Regenesys facility in Columbus, MS continued as did our efforts to reduce the weight of the elbow section housing the FTP optics. Our study of FTP measurements of submerged targets is on-going. FTP image acquisition software has been improved by incorporating selection of a dynamic region of interest. A distribution package for stereovision image acquisition has been created and installed in the stereovision computer.
Process Chemistry and Operations Planning for Hanford Waste Alternatives
Preliminary ESP calculations for the S-109 saturated salt cake dissolution test at FIU have been completed. The model predicts that > 90 of the solids mass is NaNO3 with lesser amounts of gibbsite, the Na3FSO4 double salt and sodium phosphate dodecahydrate. Improved experimental techniques at FIU resulted in the uniform preparation of all four batches of the simulant. ESP calculations correctly predicted the total height of the column as a function of run time. Concentration profiles for sodium, nitrate, nitrite, sulfate, chloride, and oxalate were in good agreement with the experimental results. Differences were observed for fluoride and for phosphate. The phosphate discrepancy was traced to database changes in going from ESP version 6.5 to 6.7. These changes have not yet been addressed with regard to porting the DBLSLTDB compilation to version 6.7; however, additional fits for this important anion are in progress.
Work on training sold - liquid equilibria data for neural network applications in the Hanford HTWOS model continued. Additional data sets were generated and tested against the base network. These values were somewhat outside the concentration regimes associated with the starting network and additional training is in progress. Plans are for DIAL project personnel to visit Hanford in August and more fully elucidate site requirements and concentration range coverage.
Aluminum solubility studies continued with solutions prepared from mixing aluminum wire with caustic. Samples in 1 and 3-m NaOH with added nitrate were made and are undergoing equilibration. This data is to add to that already obtained and extend the solubility envelopes to higher caustic loadings. Measurements in 5 and 7 m are also planned.
Flexible Scintillating Optical Fiber Sensor for Determination of Liquid Level
The primary focus of this reporting period was shielding of the liquid core waveguide from stray light. This aspect of the fiber optic sensor design is critical for eventual deployment as any significant amount of stray light reaching the detector will overpower the desired signal. The initial attempt involved placement of the liquid core waveguide inside a black rubber tube prior to connecting with the PMT. The PMT signals were monitored with and without the tubing in place, and a noticeable decrease in the background signal was observed under the former condition. Although an improvement, too much stray light is still being detected by the PMT in order for the scintillating signal to be discerned from the background. Efforts will continue toward development of an appropriate housing for the PMT as well as control programming.
Disposition of Idaho HLW Calcine
Support of ICP-SP3 Calcine Disposition Project
Mark Bricka, Brian Kauffman and Ron Palmer visited Tom Thomas and Alan Herbst at INL this month. The primary work done there was to discuss the proposed text and budget for the 2006 Cooperative Agreement. The scope of work is reasonably well organized at this time, but we are still struggling with the potential for large expenditures if we design and build a full-scale mock up of the expected process for immobilizing the calcine in grout. TCLP was run on the last of the hydroceramic-fine particle samples and on four of the grout samples. Compression testing of the recently made grout samples will be completed and reported next week.
Support of SRS Salt Disposition and Other SRS Alternatives
Support for SRS Salt Disposition Alternatives
Literature information collection for strontium, plutonium, and technetium is still ongoing. Model comparison of the potassium hydroxide, potassium nitrate, cesium hydroxide and cesium nitrate systems in water and 1 and 3-m NaOH at 25 and 50°C have been completed and tabulated for review. Strontium calculations have begun for the simple ternary systems in water. KNO3 and CsNO3 in 1 and 3-m NaOH systems are being prepared.
FIU is awaiting analytical results from the completion of the aged SRS tank 41H simulant experiment in June. When results become available, comparison of the model predictions will then be completed.
Sludge simulant composition and preparation for heel dissolution studies will be sent from the site and evaluated for use in several DASR salt simulant experiments.
On-line Analysis for Defense Waste Processing Facility
Work continues on evaluating different experimental configurations to achieve best reproducibly. To allow greater dispersion of water vapor and avoid the turbulence of the surface due to the generation of a shock wave, the pulse repetition rates of the laser were lowered from 10 to 1 Hz. The laser beam was focused directly on the slurry surface in a 2-cm diameter container, which is connected to a peristaltic pump to maintain a well mixed slurry. Single shot LIBS spectra were recorded at different experiment parameters. The data were compared to obtain the optimized conditions that give best signal-to-noise ratio as well as precision of LIBS data. The experimental configuration without the peristaltic pump to mix the slurry was also tested. However, the data was not stable due to quick sedimentation of the slurry. To overcome this problem, we are setting up the proper apparatus to reduce sedimentation of slurry during the measurement.
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
Progress on this task will be reported at a later date.
Inquiries may be addressed to:Dr. Roger King, Interim Director
205 Research Blvd.
Starkville, MS 39762-5932