DIAL's Research Highlights

Characterization of Heavy Metals, Radionuclides and Organics in Heterogeneous Media

Volatile organic compound monitoring using diode lasers. Measurements of chlorobenzene in air were carried out in February using the diode laser cavity ringdown system. A commercial standard of chlorobenzene in air was used to achieve varying partial pressures of chlorobenzene. For example, by introducing 1 Torr of the 100 parts-per-million standard into the system (a relatively easy and accurate pressure measurement), a partial pressure equivalent to 130 parts-per-billion can be achieved. This approach is being evaluated for its relative impact on the reproducibility of very low concentration data. In addition, a new gas manifold for mixing very low concentration standards of VOCs has been completed and will be installed and tested in March. We are slightly behind schedule; however, the new gas manifold should help to quickly advance our current position.Winstead, PI

Isotopically selective monitors for transuranic elements. During January, a source (U.S. Department of Energy's New Brunswick Laboratory NBL) of 97% enriched U-235 was found, and 4 m Ci of enriched uranium were ordered. Shipments from NBL ceased for two months for a physical inventory of their materials; the inventory has been completed, and shipment is expected on or about March 12. A depleted uranium standard solution (that will be mixed with the U-235 to obtain different relative isotopic abundances) has been received. Experiments aimed at optimizing the detection of uranium using CRDS continued. These efforts were carried out using depleted uranium. Isotopically resolved CRDS data should be available shortly upon arrival of the isotopically enriched standards.

The primary open issue is acquisition of isotopically pure (or at least significantly isotopically enhanced) U-235 calibration solutions. The pure/enhanced U-235 solutions are essential, since the natural abundance of U-235 is very low relative to natural U-238. For initial experiments demonstrating the ability to isotopically resolve these species and experiments to determine the accuracy of isotopic determinations for uranium, it is essential to be able to utilize solution samples having both U-235 and U-238 present in roughly comparable quantities. Also, yet to be demonstrated is whether or not the existing narrow line-width dye laser is sufficiently narrow to enable determination of uranium isotopic abundances. Comparison with earlier work suggests that this laser should have sufficient resolution to isotopically resolve selected, but not all, uranium transitions. Monts, PI

Laser-induced breakdown spectroscopy system as a process monitor and control for waste thermal treatment. Work to collect the glass spectra at different sample temperatures began. The glass sample in a crucible was placed inside the furnace which was translated slowly during data acquisition. Analytical results for the RM-29 samples collected during the CEM test in the DIAL test stand were received. The Cr concentrations obtained from LIBS data are fairly consistent with the values from the RM method. The values for Pb, Cd, and Be are all higher in the LIBS measurements than in the RM results. The reason for this inconsistency is being investigated. Singh, PI

Environmental Control Device Testing

Performance enhancement of the ionizing wet scrubber. We have ordered a volumetric powder feeder, which can be upgraded to a mass based system, for feeding particulates to the IWS. ArunKumar, PI

Testing of a ceramic regenerative heat storage device for dioxin control and heat recovery. The status of the ceramic regenerator project has not changed since last month; we are waiting for the fluid cooler to be installed so that the test stand will be operational again. Norton, PI

Transportable calibration test stand for diagnostic instrumentation. We think we have solved the secondary feed injection problem by using a different configuration on the burner. We will conduct tests using the LIBS system with calibrated solutions to verify this. ArunKumar, PI

Evaluation and performance enhancement of a submerged bed scrubber. We have been conducting extensive base line testing on the submerged bed scrubber using 1/2-inch glass marbles. Using EPA Method 5, the submerged bed scrubber efficiencies are 99.96% and better.

We are in the process of modifying the bed in order to provide continuous cleaning of the water. When running for excessive times in the current configuration, the water in the bed gets overloaded with particulates. We should finish testing by the end of the month. ArunKumar/Plodinec, PIs

Waste Treatment and D&D Support: Process Monitoring and Control

Dioxin and PCB studies. Software designed to control the test stand is being loaded onto a notebook computer and it is being networked to the test stand. The control software has been modified to include the auxiliary heaters that replace heat loss from the upper section of the test stand and from the flight tube. This computer will provide a convenient, flexible platform for controlling the test stand and recording data related to operating parameters.

The impactor has been fitted to the test stand and is ready for evaluation. An old GC has been cannibalized for its oven that will serve as the isothermal chamber for the impactor sector of the sampling system. The oven has been evaluated for operability and has been demonstrated as being able to achieve and hold the desired test temperatures.

The basic elements of the sampling system have been characterized with regard to performance criteria. Materials selection is nearing completion and arrangements have been made with suppliers to ensure that all metal parts have been inerted to limit the loss of analytes by thermal decomposition on hot metal surfaces.

A newly designed burner section for the small-scale test stand has been fabricated because those previously used developed leaks from the cooling water jacket. This new design will be evaluated in the coming month.

During the coming month, the full ensemble of the test stand, particle feeder, isothermal impactor, sampling train, control and data logging unit will the evaluated for functionality, ability to achieve and hold target operating parameters.

Design of the specialized sampling system intended to bridge between this test stand and the CRDS or REMPI instrumentation packages will be continued. Calculations based on detection limits, analyte trapping efficiency, and source concentrations will be completed. A prototype of the unit will be assembled for the purpose of verifying dimensions, flow rates, and water removal characteristics. Waggoner, PI

On-line multi-spectral imaging of thermal treatment process. Development of the IDL image processing software is now finished. We are making good progress in our efforts to develop an imaging acquisition package for use with the filter wheel; currently, the five-position filter wheel is under computer control, and we can save a user-selected number of images for any chosen filter position. We plan to add external trigger control (for time-resolved imaging) and imaging processing functions. The UV AOTF manufacturer is making progress toward completion of our system.

Progress on the instrumentation development component of this project will be slow until the UV AOTF system is received. We are on schedule now, but further delay with delivery of the UV AOTF may cause us to fall behind schedule. Monts/Su, PIs

Imaging instrumentation application and development: thermal imaging. The search for an IR camera continues. Several manufacturers have been contacted for specifications and pricing. Research on a current market-available sensor within the allocated budget continued.

A demonstration CD of the thermal imaging system on the RIC project has been created for system performance observation/evaluation. The demo CDs have been delivered to various interested parties (such as SRTC/SRS, ME/MSU).

A new version of imaging acquisition and processing drivers will be installed. Current system software packages will be tested for compatibility. Jang, PI

Imaging instrumentation application and development: profilometry. A surface roughness computation module, based on RMS height measurements, has been developed and integrated into the FTP system. Roughness measurement of all available acquired target images (both from lab and from the field) has been completed.

Integration of a higher resolution camera (for increasing the target sampling frequency) into the current system is also underway. The volume computation module will be developed and implemented in the FTP system. This module will provide the volumetric information regarding surface depository and/or wearing process. Jang, PI

Saltcake dissolution. Hanford core composite saltcake samples for FY 01 were selected from tanks U-107, BY-109, and S-110. ESP molecular streams have been generated from the base compositions and process calculations have begun. It should be noted that for these simulations ESP is being run in a predictive mode as compared to trying to reproduce the laboratory measurements. Experimental data from Herting has been received and the comparison of the model simulations for feed stability and solids dissolution calculations has started for the saltcakes from U-107 and BY-109. The waste fraction from S-110 contains a low amount of water and additional model calculations are required prior to effecting a comparison. Rebecca Toghiani visited OLI Inc. to learn about regression techniques. OLI Inc. has made some progress on fitting the data obtained in these laboratories for the Na-F-PO₄-OH system and these results will allow a comparison to data fitted for the same system here. Once completed a separate database for this system will result and will be distributed to interested parties.

Equilibrium compositions for the Na-CO₃-SO₄-OH system were prepared. Samples in water at 25 and 50°C were kept at temperature for a period of two weeks and have been worked up. PLM images of the associated crystals revealed the single component salts at 25°C and the single and double salts (depending on starting composition) at the elevated temperature. Ion chromatographic analysis of the supernates is in progress. Solutions in caustic have been prepared.

SLE experiments for the Na-F-NO₃-OH system continued. Previously samples in pure 3water were prepared and analyzed. New compositions were made for the 1, 3, and 5m OH conditions. These systems are currently equilibrating at temperature.

Presentation materials were developed for a talk to be given at the TFA Mid-Year Program Review. The meeting is scheduled for the week of March 12 in Salt Lake City. Lindner, PI

Feed stability and chemistry. Engineers at Hanford periodically use what is called the WASP model to predict particle critical velocity and specifically pressure drops through transfer lines. Recently concern has been expressed about the accuracy of these models due to the fact that they were developed for single-phase fluid systems and/or for monodisperse particles. To use these models workers have to employ an average from the particle size distribution (PSD) and this assumption may or may not predict an accurate critical velocity and pressure drop.

The slurry transport module of the Engineering Tool is currently being modified to perform PSD sensitivity studies. In these studies, simulations using several different PSDs having the same average particle size will be conducted and compared to a simulation using the average particle size. Different statistical averages will be investigated. Results from these simulations should elucidate the difference in sedimentation behavior when variable PSD and average particle size are used. Preliminary simulations revealed some differences but more simulations are needed to support that finding. Additionally, the model is being modified to account for the Non-Newtonian behavior of the slurry due to the presence of particles.

Considerable efforts were spent obtaining and analyzing data obtained from laboratory-scale salt well pumping experiments of the 241-SX-104 surrogate. A number of videotapes have been made of both plug formation and subsequent unplugging operations. Plug development for the surrogate material is initiated with a decrease in temperature that gives rise to the generation of small particles. These particles are then observed to grow and form loosely bound aggregates that were still carried along with the flow until a certain size was attained. At that point solids or gel deposition within the channel was started and a slowing down of the centerline velocity is observed eventually leading to complete plugging. Unplugging appears to occur through the channeling of water through the top layers of the plug. It is postulated that the plug exhibits a density distribution with larger particles more closely packed at the bottom of the pipe. Additional experiments at different Reynolds numbers are in progress to ascertain porosity effects within the formed gel plugs. Lindner, PI