Monthly Research Progress
Institute for Clean Energy Technology
Support of Oak Ridge Site Closure
Characterization of Corrosion for Closure of Oak Ridge Research Reactor
Because of lack of funds for the end of the federal fiscal year, our Oak Ridge collaborators were unable to provide the support required to enable deployment into the Oak Ridge Research Reactor (ORRR) pool during September. A revised deployment date is being sought.
Bio-availability and Speciation of Mercury in the Oak Ridge Ecosystem
We are continuing to summarize the comparative study of mercury in both soils and plants by the mercury analyzer and cold vapor atomic absorption spectrometer.
In January, we will design the new experiment to study the stability of mercury sulfide in rhizosphere.
Accelerating Phytoremediation by Monitoring Plant Status
We finished another round of mercury phytoremediation experiments with Chinese brake fern; this experiment used fresh soil (from MS) and was started in November. We are currently analyzing the samples and data.
Support of Hanford Single Shell Tank Waste Disposition
In-tank/At-tank Characterization for Closure of Hanford Tanks
Stereovision. Previously, we performed a series of experiments, including some in conjunction with Fourier transform profilometrys experiments simulating Hanford waste tanks at distances up to 60 feet. Analysis of the acquired images continued, with an emphasis on improving the disparity match. We also continued our efforts to optimize the experimental setup and software for deployment into the Hanford waste tanks.
Laser-induced fluorescence-spectral imaging. We began LIF experiments using 266-nm excitation and simple uranium compounds. Because of budgetary constraints, the graduate student working on this effort is being transferred to another grant.
Microwave-induced plasma-cavity ringdown spectroscopy. ICET is purchasing an optical parametric oscillator (OPO) laser system that will be operated as an ICET laser facility. In order to use the OPO laser to characterize the waste tank volatile organic compounds (VOCs), the cavity ringdown spectroscopy (CRDS) effort is constructing a portable ringdown chamber with a vacuum pump system. This mobile system can be conveniently relocated in the OPO laser facility room for ringdown measurements. Several VOCs have been selected for initial measurements. This experimental work will start when the OPO has been installed and scheduled for use. A related paper entitled "Absorption Cross-Sections of the CH Overtone of Volatile Organic Compounds: 2-Methyl-1,3-Butadiene (Isoprene), 1,3-Butadiene, and 2,3-Dimethyl-1,3-Butadiene" will be published in Applied Spectroscopy, Vol. 61(2), 2007.
Fiber optic sensors. This month we focused on developing an optical fiber gas sensor that uses a hollow optical fiber as a transducer. This is a continuation of our previous effort to develop highly sensitive active-core fiber optic gas sensors. During this month, we investigated the absorption spectrum of C2H2 and CO2 using a diode laser as a light source. The wavelength of the laser light was tuned by changing the temperature of the laser diode. The absorption spectra of C2H2 and CO2 in the wavelength region from 1529 nm to 1533 nm were thus obtained. The peak absorption wavelengths were found to be 1531.59 nm for C2H2 and 1531.06 nm for CO2. Calibration curves using the hollow optical fiber optic absorption technique for detecting C2H2 and CO2 were obtained. This hollow optical fiber absorption technique can be used to detect C2H2 down to 10 parts-per-million (ppm) and CO2 down to 50 ppm.
Fourier transform profilometry. During December, we continued development of the waste tank floor mapping algorithm that will permit individual FTP volume determinations to be stitched together to produce a comprehensive (total) volume determination. Development of the waste tank image stitching scheme is near completion. Generation of synthetic FTP images is in progress; they will be used for the FTP uncertainty analysis study and also for data validation and verification of the tank image stitching code. Preparation of the FTP Stage 1 Performance Evaluation report is nearing completion. One section (of three) of a prop simulating a curved waste tank bottom has been fabricated. As part of our gamma-radiation testing of FTP components, a SONY FCB-EX78B camera was irradiated at 216 R/hour until it no longer functioned; we are currently analyzing the periodically saved images recorded by the camera during the irradiation in order to understand how cameras fail in radioactive environments and the implications for FTP performance. The gamma-ray browning effect on the irradiated Ronchi filter and light diffuser are also under investigation.
Process Chemistry and Operations Planning for Hanford Waste Alternatives
A re-evaluation on the neural network effort was begun. Options for increasing the coverage of the primary training sets were considered including the development of a scripting program from which the number model calculations can be significantly increased. Consideration of the various products available and the ease of interfacing the scripting program with the model are in progress.
Further examination of the aluminum solubility data obtained previously was performed. Final solubility calculations indicate good agreement with the ESP model for solutions prepared in 1- and 3-m NaOH. Differences between the model predictions at 5- and 7-m caustic are being reviewed. A series of experiments evaluating the conversion of Al(OH)3 to AlOOH was begun. Solutions were prepared in 1.5-m NaOH and heated to 120°C. After three hours, 86% of the Gibbsite was converted to AlOOH. Additional experiments are in progress to evaluate this reaction at temperatures of 80 and 100°C. This reaction is of great interest owing to the difficulty of solubilizing AlOOH as compared to Al(OH)3. Earlier kinetic experiments in this laboratory have indicated that, albeit slow, the dissolution of Gibbsite is considerably faster than that of Boehmite. Assuming that substantial conversion of Gibbsite occurs at lower temperatures it will be possible to track the results to the temperature histories of the Hanford tank wastes thereby providing additional information on potential retrieval difficulties.
Disposition of Idaho HLW Calcine
Support of CH2M-WG Calcine Disposition Project
The feeders, mixers, and control equipment are now being installed on the test stand for the mock-up system. We expect to begin shakedown testing of the mock-up over the next month.
Samples were taken from one drum of the calcine simulant (non-hazardous) received in September. The chemical analysis is reported below.
We have also made two sets of cubes (17% and 34%) to test for mechanical strength. No anomalies were observed during mixing, however, neither set appears to be curing as before. We will continue to age them until after the first of the year. We will also make up a larger batch with this simulant, with the hopes that scaling up will give better results.
Support of SRS Salt Disposition and Other SRS Alternatives
Modeling and Experimental Support for High-level SRS Waste Disposition
Systems of KNO3 and NaNO3 have been prepared in water, 1-m and 3-m NaOH solutions at 25°C. These systems have reached equilibration, were filtered and are undergoing analysis.
Previous experiments on the CsNO3 and NaNO3 systems in water, 1-m and 3-m caustic continued. A number of the CsNO3 systems have failed to form solids even at concentrations approaching saturation (as based on the ESP software). Thus, additional solids have been added to the samples followed by an additional equilibration period.
Preparations are being made to participate in the SRS Al/Cr leaching workshop to be held in January in Atlanta. Results of solubility studies with Al will be reported along with examples of solids formation occurring during salt cake dissolution experiments.
Process Improvements for the Defense Waste Processing Facility (DWPF)
On-line slurry analysis. To improve LIBS measurement accuracy from resonance lines, a theoretical study of the curve of growth of spectral lines by a laser-induced plasma was performed on simulated and experimental data. The study shows that it is possible to fit the spectral line shape with the curve of growth model to obtain the self-absorption parameter for correcting self-absorption. Due to the weak Si signal from the data of simulated melter feed, we are re-examining the procedures of making the simulated melter feed. We will get the help of DWPF to find a better method to prepare the simulated melter feed for LIBS calibration. The preliminary LIBS data of CeO2 (a surrogate for Pu residue) pellet and powder demonstrated that LIBS has the capability to measure the composition of Pu residue generated during the processing of the weapons grade Pu. Work on this task is now concentrated on design of a fiber optic LIBS system for this application and testing various measurements using the pellet (no binder) kept in the press container during the measurement.
Improvement of waste throughput. X-ray diffraction (XRD) experiments on SB4 simulant with Frits 418 and 503 were begun this quarter. Materials heated to 600°C, 700°C and 800°C are being examined. It is clear that there are new phases appearing as other phases disappear with increased temperature. The detailed results will be available in January.
Discussions have been started on a task involving using ICET diagnostic instrumentation to assist with melting studies using the Cold Cap Evaluation Furnace (CEF) which has been built at SRNL. This task will be a large part of our effort in the coming year.
Support of the Fernald Silos Project
Fernald Silos Project - Remediation Process Support
Final decontamination and disposition of the Fernald building and the associated systems is ongoing. Communication with the Fernald Management Team will continue through project completion.
HEPA Filter Performance Assurance
Regenerable HEPA Filter Performance Testing
Two papers were finalized and sent for potential publication in refereed journals. At the request of the Review of Scientific Instruments editor, the two papers "Design and Evaluation of a Large-Scale Aerosol Generator" and "Design, Fabrication and Performance Characterization of a Test Stand System for the Evaluation of Nuclear Grade AG-1 HEPA Filters" were combined into one manuscript prior to final submission. The paper "An Evaluation of Environmental Protection Agency Reference Method 5I Accuracy" was submitted for publication in The Journal of the Air and Waste Management Association. Analysis of the vast amounts of data collected during the HEPA filter media velocity study was conducted.
Inquiries may be addressed to:Dr. Roger King, Interim Director
205 Research Blvd.
Starkville, MS 39762-5932