Monthly Research Progress
Institute for Clean Energy Technology
Support of Oak Ridge Site Closure
Characterization of Corrosion for Closure of Oak Ridge Research Reactor
Planning for the next deployment into the Oak Ridge research reactor (ORRR) pool continues. Construction of a new submergible metal box is nearing completion. The new submergible box is necessary because during our initial deployment of the submergible Fourier transform profilometry (FTP) system into the ORRR pool, a detectable amount of radioactive materials were deposited onto the metal box containing our instrumentation; consequently, ORNL has retained the original box. The demountable faceplate of the submergible box has been designed so as to enable FTP and stereovision to be able to sequentially record images of the same object of interest without the need to move the box or to open the box for adjustments. Efforts continue to characterize FTP spatial resolution using higher resolution cameras. An uncertainty analysis of our FTP correction methods for image distortion due to Snell's law has begun.
Bio-availability and Speciation of Mercury in the Oak Ridge Ecosystem
In May, we summarized the data from previous experiments on characterization of mercury contaminated field soils from the Oak Ridge site and on extraction of mercury sulfide from soils and sediments. We found that total mercury in three field samples from the Building 4505 trench was < = 2 mg/kg with a majority of the mercury in the non-cinnabar bound fraction. Extractability of mercury species (HgS, Hg0, and Hg2+) as well as contaminated Oak Ridge soils by 4M HNO3, concentrated HNO3, aqua regia, EPA method 3200, and saturated Na2S have been compared. In June, we will continue summarizing these results in preparation for a journal manuscript.
Accelerating Phytoremediation by Monitoring Plant Status
During the month of May, we analyzed mercury speciation in both bulk and rhizosphere soils (total 95 samples) with Indian mustard (70 pots) experiments. Due to the summer break of a Ph.D. student and an undergraduate student, the laboratory analysis slowed down. We will continue to analyze plant tissue samples (both shoots and roots) in June.
Support of Hanford Single Shell Tank Waste Disposition
In-tank/At-tank Characterization for Closure of Hanford Tanks
Stereovision. During May, we continued modifying the stereovision software to make it more user friendly. The stereo parameters are now set by command line arguments. With assistance from the FTP group, we worked to identify and solve problems with our new cameras. Two manuscripts have been prepared for submission to refereed scientific journals.
Laser-induced fluorescence-spectral imaging. During May, we continued attempts to utilize a currently available camera system until a new camera system can be purchased.
Microwave-induced plasma-cavity ringdown spectroscopy. A prototype instrument case for tank vapor analysis using cavity ringdown spectroscopy is being developed. The case can be evacuated for spectral measurements at reduced pressure in order to improve the measurement accuracy and minimize spectral overlap from different chemical species. Efforts this month focused on the evaluation of the system pressure control. Spectral measurements at different pressures will be conducted.
Fiber optic sensors. During this month, we used MSU's 137Cs gamma source to test two scintillating optical fibers for detecting gamma radiation. The first scintillating optical fiber is a CsI-doped sol-gel silica fiber. The second scintillating fiber is a liquid crystal waveguide (LCW) fiber filled with a fluoranthene solution as the scintillator. Preliminary results indicate that the CsI-doped sol-gel silica fiber can be used to detect gamma radiation. The LCW scintillating fiber with fluoranthene solution as scintillator can sense gamma radiation, but the sensitivity is very low.
Fourier transform profilometry. During May, three ICET personnel toured the Hanford site and spent a day with Hanford instrumentation and tank closure personnel, learning about current Hanford practices. Preliminary results from the first stage of simulation testing of the ICET Fourier transform profilometry (FTP) system were reported at the Hanford/Savannah River/Idaho Technical Exchange. The simulation testing is being performed as a blind test - neither the FTP nor the video camera/CAD modeling system (CCMS) analysts know the true values of the nondescript objects. The volumes (and associated uncertainties) of the nondescript objects have been determined by an independent ICET team using traditional volume determination methods. Based upon the request of Hanford personnel in our biweekly conference call, Quality Assurance/Quality Control (QA/QC) procedures have been adopted by ICET for the simulation testing. An analysis of the intrinsic FTP errors as a function of operational parameters has begun. The report on the first stage of testing is expected to be completed in June upon receipt of the CCMS results from Hanford.
Process Chemistry and Operations Planning for Hanford Waste Alternatives
Efforts continued on updating the DBLSLTDB to V7.0. The inclusion of a number of like-ion interactions and neutral-ion interactions in the Public database by OLI in this latest release of ESP has made efforts to simply port the earlier version of DBLSLTDB (compatible with V6.7) difficult. As a result, a decision was made to refit the combined literature/laboratory data sets for the systems included in DBLSLTDB, using V7 regression, the V7 Public database, and its included like-ion and neutral-ion interactions. It is believed that the neutral-ion interactions were specifically included in ESP 7.0 Public to properly account for the existence of aqueous sodium nitrate (NaNO3(aq)) at higher ionic strengths. Inclusion of these interactions between neutral sodium nitrate in the aqueous phase and other constituents allows better representation of the ionic strength of the solution - this, in turn, is very important in that the developed like-ion interactions included in DBLSLTDB are very dependent on the predicted ionic strength of the solution during modeling. Thus, efforts during May have focused on defining the necessary interactions for DBLSLTDB and obtaining parameters for these interactions through regression, while taking advantage of existing like-ion and neutral-ion interactions contained in the Public database for ESP 7.0.
Efforts in support of neural network development continued. Due to its ESP's anomalous predictions for TX-113, this salt composition will no longer be included in the training set for the neural network. Several neural net models of various complexity were trained using the seven-tank ESP dissolution calculations for comparison with previous model predictions of BY-106 saltcake dissolution. From this comparison, the neural net approach to modeling tank chemistry appears very promising. Results of the neural net effort to date were presented at the Hanford-Savannah River Technical Exchange in May 2006 and were well received.
Disposition of Idaho HLW Calcine
Support of CH2M-WG Calcine Disposition Project
We have begun obtaining estimates for equipment for the mock-up and have started discussing among ourselves just what the equipment ought to do and how it all fits into a test plan. We should be on time to meet the various schedule milestones. Informal estimates for the feeding equipment for the mock-up seem high, so we will be adjusting our specifications for the official request for bid to see about obtaining a lower price. A request for bids on the feeder equipment for the pilot scale test has been issued. A draft of the test plan for the mock-up was issued for review.
We will make up a larger batch (approximately 9 kg) of the grout waste form with the next-size-up mixer to continue looking for problems associated with scale-up next month. TCLP tests on representative samples from the large batch made up last month were completed. Again, one of the 34% samples failed for chromium. All others passed.
A draft of the paper for the American Ceramic Society's fall meeting will be sent out for review early next month.
Support of SRS Salt Disposition and Other SRS Alternatives
Modeling and Experimental Support for High-level SRS Waste Disposition
Results and comparisons to the model for the DASR 38H simulant with 3% by weight sludge were compiled and presented at the Hanford/Savannah River/Idaho Technology Exchange held in Richland, WA on May 16 - 18, 2006. Included in the presentation were results of modeling and experimental comparisons for two FIU tall column experiments: SRS 41 aged simulant (over three years) and the Hanford S109 simulant-saturated.
A new DASR experiment using the remaining 38H simulant with 1.5% by weight has begun in order to compare dissolution times, concentrations, and modeling to the 38H simulant experimental results having no sludge and with the experimental results of the 38H simulant containing 3% sludge by weight. Also, new solubility modeling for the CsNO3-KNO3-Water, 1,3 m NaOH systems has been completed and experiments will begin in June.
Process Improvements for the Defense Waste Processing Facility (DWPF)
To obtain simultaneous multi-element calibrations, we realigned the optics to use an Echelle spectrometer as the detection system. The new version of the Echelle spectrometer data acquisition software allows us to effectively control laser firing and record the predefined region of interest during the data acquisition. The initial data recorded with a 10-Hz laser show around 10% relative standard deviation. This is related to sample splashing and ripples by laser induced shock wave. The use of lower laser frequency will improve the measurement precision. However, measurements using the Echelle spectrometer as a master to keep laser frequency to 5 Hz shows a poorer LIBS signal. This is due to at least 10% laser pulse energy reduction with 5 Hz as compared with 10 Hz because of a change in the thermal lens inside the laser resonator. We are currently testing another method, which maintains the laser flash lamp frequency at 10 Hz but has a 5-Hz laser output for LIBS measurement. This method should not degrade the laser pulse energy or beam quality. In an attempt to obtain LIBS signal of simulated melter feed, we found the intensity of Si lines were generally weak. By comparing the data from the samples that contained the same amount of Si by either adding frit or SiO2, we found that the data from the SiO2 addition had a higher Si line intensity. Since frit is in a form of bold grain, it is hard to completely dissolve in sludge. The use of different concentrations of SiO2 in sludge to produce the Si calibration for simulated melter feed will need careful examination because of the different properties between the frit and SiO2 chemical compounds.
Improvement of waste throughput. We visited the Savannah River Research Facility this month and spoke with those working on improving the melt rate and waste loading properties of the DWFP glasses. We had a tour of the laboratories and some excellent discussions with some of the researchers there. Optical microscopy of the samples made from the various frits and waste simulants is continuing.
Support of the Fernald Silos Project
Fernald Silos Project - Remediation Process Support
Waste disposition. Dismantlement and disposition of the glove boxes was completed. Bionomics provided the disposal containers. Preliminary surveys of the glove box exteriors and the building were taken. No contamination was found. Final survey and release of the building will be completed in June 2006.
HEPA Filter Performance Assurance
During May, a HEPA filter was loaded from 1.3 to 6 in. w.c. at a media velocity of 6 ft/min. Gravimetric analysis revealed that more test particulate was capture on the filter than predicted based on previous media velocity testing. This appears to be due to the test particulate having a slight larger count mean diameter than previous tests. The test will be repeated in June. Calculations were made that convert standard cubic feet per minute to actual cubic feet per minute, with respect to flow though the HEPA filter test stand. We began writing a manuscript to be submitted to Reviews of Scientific Instruments describing the ICET aerosol generator.
Inquiries may be addressed to:Dr. Roger King, Interim Director
205 Research Blvd.
Starkville, MS 39762-5932