DIAL's Research Highlights
Diagnostic Instrumentation & Analysis Laboratory
Support of Closure Sites
Fernald Silos Project Monitoring and Control Integration
Waste disposition. Discussions were held regarding the disposition of the remaining Fernald K-65 material, the grout samples, the laboratory trash, and the building trash. DIAL began packaging the waste for shipment to Fernald. Certified drums have been ordered. The material is currently packaged in 30 and 55-gallon drums. These containers will be over-packed into 55-gallon and 85-gallon drums certified for low-level radiological shipments.
The following activities are planned for the upcoming months:
Accelerating Phytoremediation by Monitoring Plant Status
During the month of November, we have been analyzing samples and data from previous experiments on mercury phytoremediation. During this month, we visited the DOE Oak Ridge site and obtained some documents on mercury contamination survey and remediation. We have also discussed with ORNL personnel about getting soil samples to DIAL.
Bio-availability and Speciation of Mercury in the Oak Ridge Ecosystem
In November, we visited the US DOE Information Center in Oak Ridge, TN. We obtained much first-hand information on geological characteristics, land use, and previous studies on mercury contamination and remediation efforts. We are still in the process of getting actual mercury contaminated soils from Y 12 plants at Oak Ridge. At the same time, we continued conducting pilot scale experiments to study the bioavailability and kinetics of different mercury species (such as nitrate, chloride, elemental, and sulfide) in Oak Ridge soil at three moisture regimes. These regimes include air-dry, field capacity, and saturated moisture regime. We have finished four sets of sampling and sequential selective dissolution analyses aiming at studying the kinetics of mercury transformation among major biogeochemical solid phase components in soils under different redox conditions.
In December, we will start to revise our manuscript submitted to Science of Total Environment. We have gotten comments from reviewers. In addition, we will continue our analytical efforts and summarize the results.
Support of Hanford Single Shell Tank Waste Disposition
In-tank/At-tank Characterization for Closure of Hanford Tanks
Stereovision. During November, we tested the newly improved stereovision system (with new image acquisition board and cameras with greater zoom capability). Using the upgraded system, we have begun to search for optimum operational parameters that lead to better disparity maps (and hence better resolution).
Laser-induced fluorescence-spectral imaging. During November, we continued experiments on simple uranyl compounds mixed at a variety of concentrations with other solid materials (in this case, sand). These experiments will enable us to determine the limits of detection for LIF spectral imaging detection of uranyl compounds in mixtures.
Microwave-induced plasma-cavity ringdown spectroscopy. This month, the experimental work was temporarily stopped. The ultraviolet spectrometer was not functioning properly due to the extensive use. Our efforts were focused on data analysis. The experimental work will be resumed when the spectrometer is fixed.
Fiber optic sensors. During November, the photomultiplier tube (PMT) used for the photo counting was sent to Hamamatsu Photonics. Inc. for repair due to the blast of a fuse in side the PMT. The repaired PMT was sent back to us and assembled into the shielding package fabricated last month. The dark count of the PMT with/without this package was detected and compared with a computer program developed in September. The tests were carried out in the laboratory with normal illumination lights turned on. Without the package, the dark count is > 106 counts/sec, even when the PMT was covered with a black cloth. With the package, the dark count is < 50 counts/sec. The dark count data provided by Hamamatsu Photonics, Inc. is ca. 100 counts/sec. Therefore, the package design for the PMT and fiber optic system works as expected.
Fourier transform profilometry. Study of FTP measurements for submerged targets continued. During November, 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 set-up on top of the tank's riser. We are working with Hanford to investigate the possible use of a currently accepted camera system for the FTP probe.
Process Chemistry and Operations Planning for Hanford Waste Alternatives
Analysis of the aluminum samples is continuing. Most of the samples are approaching equilibrium but additional time is needed to confirm that concentrations have become constant.
Revisions to the DIAL/MSU DBLSLTDB database, needed to port the compilation of ESP version 6.7 were completed. The database was then distributed to workers at HNF and at SRS.
Additional ESP calculations were also performed in support of the neural network development for the HNF HTWOS simulator. These were designed to evaluate the predictions of the network upon dissolution of a few waste components. Additional extension of the original training sets is planned.
A manuscript entitled "Modeling of Pilot-scale Salt Cake Dissolution," was accepted for the Waste Management 2006 Conference. Reviewer comments were received and are being addressed followed by formal submission of the paper. The work centers on a comparison of the pilot-scale dissolution experiments conducted at FIU with ESP model predictions. Two extreme conditions of waste hydrology were evaluated. In the case of a dry salt cake, additional flowsheet operations were required to attain agreement between the experimental results and the model predictions. For a saturated salt cake, a standard model flowsheet was all that was required.
Flexible Scintillating Optical Fiber Sensor for Determination of Liquid Level
The PMT used for photo counting was sent to Hamamatsu Photonics, Inc. for repair due to the blast of a fuse inside the PMT. The repaired PMT was sent back to us. The PMT was assembled into the shielding package fabricated last month.
A computer program was developed for reading the photon counting signal from the PMT. The dark count of the PMT with/without this package was detected and compared with the newly developed computer program. The tests were carried out in the laboratory with normal illumination turned on. Without the package, the dark count is > 106 counts/s even when the PMT was covered with a black cloth. With the package, the dark count is < 50 counts/s. The dark count data provided by Hamamatsu Photonics, Inc. is ca. 100 counts/s. Therefore, the package design for the PMT and fiber optic system work as expected.
Disposition of Idaho HLW Calcine
Support of ICP-SP3 Calcine Disposition Project
The annual report was issued to INL.
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. A new set of formulations based around the 1:0.5:0.5 (cement:slag:flyash) composition was fabricated and tested. There was an unusual variability in the compressive strength that we are puzzling over. We discussed these results with our customer and devised another set of tests. Our next set was a large cohort of the formulation of OPC:slag:fly ash of 1.0:0.5:0.5 to try to get a handle on the real range of strengths that might be expected from this process. We made a group of ten cubes (from five batches) over the course of one day, using the same mixing protocol, cured them all together (nine days), and tested them all together.
Only one of the samples was stronger than 500 psi. The mixing time for all of these was ten minutes. The OPC:slag:fly ash elements were added one component at a time rather than sampling from a much larger batch of pre-mixed material. Some of the samples were still moist even after more than a week of curing. Examining the material after fracture found some of them to be very friable on the inside. We intend to examine all the cubes that have been made from this formulation to see if we can pick up any clues from the broken pieces. We could do optical microscopy or differential scanning calorimetry (DSC) to try to characterize these materials. We will also contact the group that has the x-ray diffractometer (XRD) on campus to see if it might be available. To determine whether it is the mixing time, we will do another set of the same formulation with a mixing time of 30 minutes.
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 are approaching equilibrium for all samples prepared at 50°C. Analytical results for the 25°C potassium and cesium systems have been compared to literature data and are undergoing statistical analysis.
The DASR small column experiment began the middle of this month using the SRS 38H simulant prepared earlier and approximately three percent by weight SRS Tank 8 sludge simulant prepared from the recipe developed at the site. The experiment is being maintained at 30°C in the environmental chamber and a total of nine fractions have been collected to date.
On-line Analysis for Defense Waste Processing Facility
In order to prepare the simulated melter feed in our laboratory for LIBS calibration, we used the sludge receipt and adjustment tank (SRAT) product and frits provided by DWPF to make the slurry with different elemental compositions. The initial test was performed on the Li calibration. The slurry samples containing Li concentration from 0 to 0.5% were prepared. LIBS data of these samples were recorded. A linear Li calibration data was obtained from these data. Accuracy for Li concentrations greater than 2% can be achieved from these data. The sample spattering from the slurry surface due to laser-induced shock wave is a major problem for LIBS measurements in slurry type samples. It results in sample loss and the possibility of contamination of the optics. We are redesigning the sampling system to solve this problem. The DWPF sent a bottle of standard glass for acceptance testing of low-activity waste glass. We will evaluate the feasibility of correlating the glass data with the slurry data.
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 heating/melting has been done. We have started the optical microscopy. That and the differential scanning calorimetry (DSC) will be completed in December.
HEPA Filter Performance Assurance
Regenerable HEPA Filter Performance Testing
HEPA filter media velocity testing was the focus of the HEPA group. The testing entailed loading the filters with a KCl test particulate from their initial dP to approximately 6 in. w.c. Upstream PSD and mass loading rates were determined through the use of an SMPS, APS, and ELPI, while downstream measurements were made with a CPC and LPC. Tests were completed for 4, 5, 6, and 7 ft/min media velocities.
Inquiries may be addressed to:Dr. Roger King, Interim Director
205 Research Blvd.
Starkville, MS 39762-5932