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3-Nitropropionic Acid is a Suicide Inhibitor of MitochondrialRespiration that, Upon Oxidation by Complex II, Forms a Covalent AdductWith a Catalytic Base Arginine in the Active Site of the Enzyme (open access)

3-Nitropropionic Acid is a Suicide Inhibitor of MitochondrialRespiration that, Upon Oxidation by Complex II, Forms a Covalent AdductWith a Catalytic Base Arginine in the Active Site of the Enzyme

We report three new structures of mitochondrial respiratory Complex II (succinate ubiquinone oxidoreductase, E.C. 1.3.5.1) at up to 2.1 {angstrom} resolution, with various inhibitors. The structures define the conformation of the bound inhibitors and suggest the residues involved in substrate binding and catalysis at the dicarboxylate site. In particular they support the role of Arg297 as a general base catalyst accepting a proton in the dehydrogenation of succinate. The dicarboxylate ligand in oxaloacetate-containing crystals appears to be the same as that reported for Shewanella flavocytochrome c treated with fumarate. The plant and fungal toxin 3-nitropropionic acid, an irreversible inactivator of succinate dehydrogenase, forms a covalent adduct with the side chain of Arg297. The modification eliminates a trypsin cleavage site in the flavoprotein, and tandem mass spectroscopic analysis of the new fragment shows the mass of Arg 297 to be increased by 83 Da and to have potential of losing 44 Da, consistent with decarboxylation, during fragmentation.
Date: December 1, 2005
Creator: Huang, Li-shar; Sun, Gang; Cobessi, David; Wang, Andy C.; Shen,John T.; Tung, Eric Y. et al.
System: The UNT Digital Library
8 GeV H- ions: Transport and injection (open access)

8 GeV H- ions: Transport and injection

Fermilab is working on the design of an 8 GeV superconducting RF H{sup -} linac called the Proton Driver. The energy of H{sup -} beam will be an order of magnitude higher than the existing ones. This brings up a number of technical challenges to transport and injection of H{sup -} ions. This paper will focus on the subjects of stripping losses (including stripping by blackbody radiation, field and residual gas) and carbon foil stripping efficiency, along with a brief discussion on other issues such as Stark states lifetime of hydrogen atoms, single and multiple Coulomb scattering, foil heating and stress, radiation activation, collimation and jitter correction, etc.
Date: May 1, 2005
Creator: Chou, W.; Bryant, H.; Drozhdin, A.; Hill, C.; Kostin, M.; Macek, R. et al.
System: The UNT Digital Library
17.5% p-Type Silicon Heterojunction Solar Cells with HWCVD a-Si:H as the Emitter and Back Contact (open access)

17.5% p-Type Silicon Heterojunction Solar Cells with HWCVD a-Si:H as the Emitter and Back Contact

Thin hydrogenated amorphous silicon (a-Si:H) layers deposited by hot-wire chemical vapor deposition (HWCVD) are used as both emitters and back contacts in silicon heterojunction solar cells. Low interface recombination velocity and high open-circuit voltage are achieved by a low substrate temperature (<150 deg C) intrinsic a-Si:H deposition which ensures immediate amorphous silicon deposition. This is followed by deposition of doped a-Si:H at a higher temperature (>200 deg C) which appears to improve dopant activation. With an i/n a-Si:H emitter, we obtain a confirmed efficiency of 17.1% on textured p-type float-zone (FZ) silicon with a screen-printed aluminum back-surface-field (Al-BSF) contact. Employing a-Si:H as both the front emitter and the back contact, we achieve a confirmed efficiency of 17.5%, the highest reported efficiency for a p-type c-Si based heterojunction solar cell.
Date: November 1, 2005
Creator: Wang, T. H.; Page, M. R.; Iwaniczko, E.; Wang, Q.; Xu,Y.; Yan, Y. et al.
System: The UNT Digital Library
21-kW Thin-Film PV Technology Validation -- An NREL/Solar Energy Centre of India MOU Cooperative Project (open access)

21-kW Thin-Film PV Technology Validation -- An NREL/Solar Energy Centre of India MOU Cooperative Project

This paper summarizes findings during a one-week (27-31 October 2003) site visit to the Thin-Film Technology Test Bed at India's Solar Energy Centre (SEC) near New Delhi. The U.S. and Indian governments signed a Memorandum of Understanding in March 2000 to undertake a 50-50 cost-shared 21-kW thin-film PV technology validation project to evaluate the performance of thin-film photovoltaic (PV) modules under Indian climatic conditions. This project benefits Indian researchers by giving them experience with cost-effective PV materials, and it benefits the United States because data will be sent to the appropriate U.S. thin-film PV manufacturers for evaluation and analysis. During the visit, NREL personnel engaged in technical discussions regarding thin-film PV technologies with Ministry of Non-Conventional Energy Sources engineers and scientists. Issues included inspecting the newly constructed arrays, discussing better methods of electrically loading the PV arrays, taking I-V traces, and gathering baseline I-V data.
Date: January 1, 2005
Creator: McNutt, P. F. & Ullal, H. S.
System: The UNT Digital Library
53 MHz beam loading compensation for slip stacking in the Fermilab Main Injector (open access)

53 MHz beam loading compensation for slip stacking in the Fermilab Main Injector

Recently In-Phase and Quadrature (I&amp;Q) was added to both the 53 MHz Feedback and Feedforward Beam Loading Compensation for Slip Stacking in the Fermilab Main Injector. With 53 MHz Feedback, we can now turn the 18 Radio Frequency (RF) Stations off down to below 100 V. In using I&amp;Q on Feedforward, beam loading compensation to the beam on both the upper and lower frequencies of Slip Stacking can be applied as we slip the beam. I&amp;Q theory will be discussed.
Date: May 1, 2005
Creator: Dey, J. & Kourbanis, I.
System: The UNT Digital Library
The 100,000 amp dc power supply for a staged hadron collider super ferric magnet (open access)

The 100,000 amp dc power supply for a staged hadron collider super ferric magnet

A 1.5 volt 100,000 amp DC switcher power supply was developed for testing a superferric magnet string at FNAL. This supply was used during testing as both the ramping supply and holding supply powering a single magnet load with a total load resistance of 0.7{micro} Ohms. The supply consists of ten paralleled switcher cells, powered by a 400 volt/600 Amp DC power supply. Each cell consists of an IGBT H-bridge driving a step-down transformer at a switching frequency of 2 kHz. The transformer has an effective turns ratio of 224:1. The secondary consists of 32 parallel single-turn full wave rectifier windings. The rectification is done with 64 Shottky diodes. Each cell is rated at 1.5 volts/10,000 amps. During this test each cell was operated as a constant power source without load current or field feedback. This paper will describe the design of the switcher cell and control system used during testing. We will also describe the next level of improvements to the current feedback system to improve the ramp control.
Date: September 1, 2005
Creator: Hays, Steven L.; Claypool, Bradley & Foster, G. William
System: The UNT Digital Library
The 100 kA current leads for a superconducting transmission line magnet (open access)

The 100 kA current leads for a superconducting transmission line magnet

A pair of current leads to power a transmission line magnet cooled at liquid helium temperature has been designed and developed at Fermilab. The leads designed to carry 100 kA dc current. Each lead consists of a warm end, heat exchange section and a cold end. The warm end is a half moon plate and cylinder brazed together. The heat exchange section is made of 202 copper rods arranged in a staggered pattern. Each rod is 6.35 mm in diameter and 1650 mm in length. The rods were soft-soldered into 12.7 mm deep holes at both warm and cold ends. The helium gas flow, guided by anodized aluminum baffles along the lead length, allows for a relatively high heat transfer coefficient between the current carrying rods and cooling helium gas. As a result the current leads were successfully tested with a ramping current of up to 104 kA. The current lead design, assembly work and the test results are presented.
Date: September 1, 2005
Creator: Huang, Yuenian; Foster, William; Kim, Seog-Whan; Mazur, Peter; Oleck, Andrew; Piekarz, Henryk et al.
System: The UNT Digital Library
15th Workshop on Crystalline Silicon Solar Cells and Modules: Materials and Processes; Extended Abstracts and Papers (open access)

15th Workshop on Crystalline Silicon Solar Cells and Modules: Materials and Processes; Extended Abstracts and Papers

The National Center for Photovoltaics sponsored the 15th Workshop on Crystalline Silicon Solar Cells & Modules: Materials and Processes, held in Vail, CO, August 7-10, 2005. This meeting provided a forum for an informal exchange of technical and scientific information between international researchers in the photovoltaic and relevant non-photovoltaic fields. The workshop addressed the fundamental properties of PV silicon, new solar cell designs, and advanced solar cell processing techniques. A combination of oral presentations by invited speakers, poster sessions, and discussion sessions reviewed recent advances in crystal growth, new cell designs, new processes and process characterization techniques, and cell fabrication approaches suitable for future manufacturing demands. The theme of this year's meeting was 'Providing the Scientific Basis for Industrial Success.' Specific sessions during the workshop included: Advances in crystal growth and material issues; Impurities and defects in Si; Advanced processing; High-efficiency Si solar cells; Thin Si solar cells; and Cell design for efficiency and reliability module operation. The topic for the Rump Session was ''Si Feedstock: The Show Stopper'' and featured a panel discussion by representatives from various PV companies.
Date: November 1, 2005
Creator: Sopori, B. L.
System: The UNT Digital Library
2005 DOE Hydrogen Program Review PresentationCOST AND PERFORMANCE ENHANCEMENTS FOR A PEM FUEL CELL TURBOCOMPRESSOR (open access)

2005 DOE Hydrogen Program Review PresentationCOST AND PERFORMANCE ENHANCEMENTS FOR A PEM FUEL CELL TURBOCOMPRESSOR

The objectives of the program during the past year was to complete Technical Objectives 2 and 3 and initiate Technical Objective 4 are described. To assist the Department of Energy in the development of a low cost, reliable and high performance air compressor/expander. Technical Objective 1: Perform a turbocompressor systems PEM fuel cell trade study to determine the enhanced turbocompressor approach. Technical Objective 2: Using the results from technical objective 1, an enhanced turbocompressor will be fabricated. The design may be modified to match the flow requirements of a selected fuel cell system developer. Technical Objective 3: Design a cost and performance enhanced compact motor and motor controller. Technical Objective 4: Turbocompressor/motor controller development.
Date: April 1, 2005
Creator: Gee, Mark K.
System: The UNT Digital Library
2005 Laser Diagnostics in Combustion Gordon Conference July 31-August 5, 2005 (open access)

2005 Laser Diagnostics in Combustion Gordon Conference July 31-August 5, 2005

The Gordon Research Conference (GRC) on LASER DIAGNOSTICS IN COMBUSTION was held at Mount Holyoke College from 7/31/2005 thru 8/5/2005. The Conference was well-attended with 121 participants (attendees list attached). The attendees represented the spectrum of endeavor in this field coming from academia, industry, and government laboratories, both U.S. and foreign scientists, senior researchers, young investigators, and students. In designing the formal speakers program, emphasis was placed on current unpublished research and discussion of the future target areas in this field. There was a conscious effort to stimulate lively discussion about the key issues in the field today. Time for formal presentations was limited in the interest of group discussions. In order that more scientists could communicate their most recent results, poster presentation time was scheduled. Attached is a copy of the formal schedule and speaker program and the poster program. In addition to these formal interactions, ''free time'' was scheduled to allow informal discussions. Such discussions are fostering new collaborations and joint efforts in the field. I want to personally thank you for your support of this Conference. As you know, in the interest of promoting the presentation of unpublished and frontier-breaking research, Gordon Research Conferences does not permit …
Date: August 1, 2005
Creator: Allen, Mark G.
System: The UNT Digital Library
3D Magnetotelluric characterization of the COSO GeothermalField (open access)

3D Magnetotelluric characterization of the COSO GeothermalField

Knowledge of the subsurface electrical resistivity/conductivity can contribute to a better understanding of complex hydrothermal systems, typified by Coso geothermal field, through mapping the geometry (bounds and controlling structures) over existing production. Three-dimensional magnetotelluric (MT) inversion is now an emerging technology for characterizing the resistivity structures of complex geothermal systems. The method appears to hold great promise, but histories exploiting truly 3D inversion that demonstrate the advantages that can be gained by acquiring and analyzing MT data in three dimensions are still few in number. This project will address said issue, by applying 3D MT forward modeling and inversion to a MT data set acquired over the Coso geothermal field. The goal of the project is to provide the capability to image large geothermal reservoirs in a single self-consistent model. Initial analysis of the Coso MT data has been carried out using 2D MT imaging technology to construct an initial 3D resistivity model from a series of 2D resistivity images obtained using the inline electric field measurements (Zxy impedance elements) along different measurement transects. This model will be subsequently refined through a 3D inversion process. The initial 3D resistivity model clearly shows the controlling geological structures possibly influencing well production …
Date: January 1, 2005
Creator: Newman, Gregory A.; Hoversten, Michael; Gasperikova, Erika & Wannamaker, Philip E.
System: The UNT Digital Library
About NICADD extruded scintillating strips (open access)

About NICADD extruded scintillating strips

The results of control measurements of extruded scintillating strip responses to a radioactive source Sr-90 are provided, and details of strip choice, preparation, and method of measurement are included. About four hundred one meter long extruded scintillating strips were measured at four different points. These results were essential for prototyping a tail catcher and muon tracker for a future international electron positron linear collider detector.
Date: April 1, 2005
Creator: Dyshkant, A.; Beznosko, D.; Blazey, G.; Chakraborty, D.; Francis, K.; Kubik, D. et al.
System: The UNT Digital Library
Absolute calibration of the Auger fluorescence detectors (open access)

Absolute calibration of the Auger fluorescence detectors

Absolute calibration of the Pierre Auger Observatory fluorescence detectors uses a light source at the telescope aperture. The technique accounts for the combined effects of all detector components in a single measurement. The calibrated 2.5 m diameter light source fills the aperture, providing uniform illumination to each pixel. The known flux from the light source and the response of the acquisition system give the required calibration for each pixel. In the lab, light source uniformity is studied using CCD images and the intensity is measured relative to NIST-calibrated photodiodes. Overall uncertainties are presently 12%, and are dominated by systematics.
Date: July 1, 2005
Creator: Bauleo, P.; Brack, J.; Garrard, L.; Harton, J.; Knapik, R.; Meyhandan, R. et al.
System: The UNT Digital Library
Absolute X-Ray Yields from Laser-Irradiated, Ge-doped Aerogel Targets (open access)

Absolute X-Ray Yields from Laser-Irradiated, Ge-doped Aerogel Targets

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Date: July 1, 2005
Creator: Fournier, K. B.; Tobin, M.; Poco, J. F.; Bradley, K.; Coverdale, C. A.; Beutler, D. et al.
System: The UNT Digital Library
Abundance of Green Tree Frogs and Insects in Artificial Canopy Gaps in a Bottomland Hardwood Forest. (open access)

Abundance of Green Tree Frogs and Insects in Artificial Canopy Gaps in a Bottomland Hardwood Forest.

ABSTRACT - We found more green tree frogs ( Hyla cinerea) n canopv gaps than in closed canopy forest. Of the 331 green tree frogs observed, 88% were in canopv gaps. Likewise, higher numbers and biomasses of insects were captured in the open gap habitat Flies were the most commonlv collected insect group accounting for 54% of the total capture. These data suggest that one reason green tree frogs were more abundant in canopy gaps was the increased availability of prey and that small canopy gaps provide early successional habitats that are beneficial to green tree frog populations.
Date: April 1, 2005
Creator: Horn, Scott; Hanula, James, L.; Ulyshen, Michael D. & Kilgo, John, C.
System: The UNT Digital Library
Abundance of green tree frogs and insects in artificial canopy gaps in a bottomland hardwood forest. (open access)

Abundance of green tree frogs and insects in artificial canopy gaps in a bottomland hardwood forest.

Horn, Scott, James L. Hanula, Michael D. Ulyshen, and John C. Kilgo. 2005. Abundance of green tree frogs and insects in artificial canopy gaps in a bottomland hardwood forest. Am. Midl. Nat. 153:321-326. Abstract: We found more green tree frogs (Hyla cinerea) in canopy gaps than in closed canopy forest. Of the 331 green tree frogs observed, 88% were in canopy gaps. Likewise, higher numbers and biomasses of insects were captured in the open gap habitat. Flies were the most commonly collected insect group accounting for 54% of the total capture. These data suggest that one reason green tree frogs were more abundant in canopy gaps was the increased availability of prey and that small canopy gaps provide early successional habitats that are beneficial to green tree frog populations.
Date: January 1, 2005
Creator: Horn, Scott; Hanula, James L.; Ulyshen, Michael D. & Kilgo, John C.
System: The UNT Digital Library
Achievement of Low Emissions by Engine Modification to Utilize Gas-to-Liquid Fuel and Advanced Emission Controls on a Class 8 Truck (open access)

Achievement of Low Emissions by Engine Modification to Utilize Gas-to-Liquid Fuel and Advanced Emission Controls on a Class 8 Truck

A 2002 Cummins ISM engine was modified to be optimized for operation on gas-to-liquid (GTL) fuel and advanced emission control devices. The engine modifications included increased exhaust gas recirculation (EGR), decreased compression ratio, and reshaped piston and bowl configuration.
Date: November 1, 2005
Creator: Alleman, T. L.; Tennant, C. J.; Hayes, R. R.; Miyasato, M.; Oshinuga, A.; Barton, G. et al.
System: The UNT Digital Library
Active Nuclear Material Detection and Imaging (open access)

Active Nuclear Material Detection and Imaging

An experimental evaluation has been conducted to assess the operational performance of a coded-aperture, thermal neutron imaging system and its detection and imaging capability for shielded nuclear material in pulsed photonuclear environments. This evaluation used an imaging system developed by Brookhaven National Laboratory. The active photonuclear environment was produced by an operationallyflexible, Idaho National Laboratory (INL) pulsed electron accelerator. The neutron environments were monitored using INL photonuclear neutron detectors. Results include experimental images, operational imaging system assessments and recommendations that would enhance nuclear material detection and imaging performance.
Date: October 1, 2005
Creator: Norman, Daren; Jones, James; KevinHaskell; Vanmier, Peter E. & Forman, Leon
System: The UNT Digital Library
Adsorption of lanthanum to goethite in the presence of gluconate (open access)

Adsorption of lanthanum to goethite in the presence of gluconate

Adsorption of Lanthanum to Goethite in the Presence of Gluconic Acid L. C. HULL,1 S. E. PEPPER2 AND S. B. CLARK2 1Idaho National Engineering and Environmental Laboratory, Idaho Falls, ID (hulllc@inel.gov) 2Washington State University, Pullman, WA (spepper@wsu.edu), (s_clark@wsu.edu) Lanthanide and trivalent-actinide elements in radioactive waste can pose risks to humans and ecological systems for many years. Organic complexing agents, from natural organic matter or the degradation of waste package components, can alter the mobility of these elements. We studied the effect of gluconic acid, as an analogue for cellulose degradation products, on the adsorption of lanthanum, representing lanthanide and trivalent-actinide elments, to goethite, representing natural iron minearals and degradation products of waste packages. Batch pH adsorption edge experiments were conducted with lanthanum alone, and with lanthanum and gluconate at a 1:1 mole ratio. Lanthanum concentrations studied were 0.1, 1, and 10 mM, covering a range from 10% to 1000% of the calculated available adsorption sites on goethite. In the absence of gluconate, lanthanum was primarily present in solution as free lanthanum ion. With gluconate present, free lanthanum concentration in solution decreased with increasing pH as step-wise deprotonation of the gluconate molecule increased the fraction lanthanum complexed with gluconate. Adsorption to …
Date: May 1, 2005
Creator: Hull, Laurence C.; Pepper, Sarah & Clark, Sue
System: The UNT Digital Library
Advanced Heat Transfer and Thermal Storage Fluids (open access)

Advanced Heat Transfer and Thermal Storage Fluids

The design of the next generation solar parabolic trough systems for power production will require the development of new thermal energy storage options with improved economics or operational characteristics. Current heat-transfer fluids such as VP-1?, which consists of a eutectic mixture of biphenyl and diphenyl oxide, allow a maximum operating temperature of ca. 300 C, a limit above which the vapor pressure would become too high and would require pressure-rated tanks. The use of VP-1? also suffers from a freezing point around 13 C that requires heating during cold periods. One of the goals for future trough systems is the use of heat-transfer fluids that can act as thermal storage media and that allow operating temperatures around 425 C combined with lower limits around 0 C. This paper presents an outline of our latest approach toward the development of such thermal storage fluids.
Date: January 1, 2005
Creator: Moens, L. & Blake, D.
System: The UNT Digital Library
Advanced Indoor Module Light-Soaking Facility (open access)

Advanced Indoor Module Light-Soaking Facility

An overview of the accelerated, indoor light-soaking test station is presented in this paper, along with data obtained for six modules that underwent exposure. The station comprises a climate-controlled chamber equipped with a solar simulator that allows 1-sun light intensity exposure. Concurrently, we monitor the electrical characteristics of multiple PV modules and exercise active control over their electrical bias using programmable electronic loads, interfaced to a data acquisition system that acquires power-tracking and current-voltage data. This capability allows us to the test different bias conditions and to cyclically alternate between them. Additionally, we can vary the light intensity and module temperatures to garner realistic temperature coefficients of module performance. Data obtained on cadmium telluride (CdTe) and amorphous silicon (a-Si) modules are presented.
Date: January 1, 2005
Creator: del Cueto, J. A.; Osterwald, C. & Pruett, J.
System: The UNT Digital Library
Advanced Intermediate Heat Transport Loop Design Configurations for Hydrogen Production Using High Temperature Nuclear Reactors (open access)

Advanced Intermediate Heat Transport Loop Design Configurations for Hydrogen Production Using High Temperature Nuclear Reactors

The US Department of Energy is investigating the use of high-temperature nuclear reactors to produce hydrogen using either thermochemical cycles or high-temperature electrolysis. Although the hydrogen production processes are in an early stage of development, coupling either of these processes to the high-temperature reactor requires both efficient heat transfer and adequate separation of the facilities to assure that off-normal events in the production facility do not impact the nuclear power plant. An intermediate heat transport loop will be required to separate the operations and safety functions of the nuclear and hydrogen plants. A next generation high-temperature reactor could be envisioned as a single-purpose facility that produces hydrogen or a dual-purpose facility that produces hydrogen and electricity. Early plants, such as the proposed Next Generation Nuclear Plant (NGNP), may be dual-purpose facilities that demonstrate both hydrogen and efficient electrical generation. Later plants could be single-purpose facilities. At this stage of development, both single- and dual-purpose facilities need to be understood. A number of possible configurations for a system that transfers heat between the nuclear reactor and the hydrogen and/or electrical generation plants were identified. These configurations included both direct and indirect cycles for the production of electricity. Both helium and liquid …
Date: November 1, 2005
Creator: Oh, Chang; Davis, Cliff; Barner, Rober & Pickard, Paul
System: The UNT Digital Library
Advanced Off-Gas Control System Design For Radioactive And Mixed Waste Treatment (open access)

Advanced Off-Gas Control System Design For Radioactive And Mixed Waste Treatment

Treatment of radioactive and mixed wastes is often required to destroy or immobilize hazardous constituents, reduce waste volume, and convert the waste to a form suitable for final disposal. These kinds of treatments usually evolve off-gas. Air emission regulations have become increasingly stringent in recent years. Mixed waste thermal treatment in the United States is now generally regulated under the Hazardous Waste Combustor (HWC) Maximum Achievable Control Technology (MACT) standards. These standards impose unprecedented requirements for operation, monitoring and control, and emissions control. Off-gas control technologies and system designs that were satisfactorily proven in mixed waste operation prior to the implementation of new regulatory standards are in some cases no longer suitable in new mixed waste treatment system designs. Some mixed waste treatment facilities have been shut down rather than have excessively restrictive feed rate limits or facility upgrades to comply with the new standards. New mixed waste treatment facilities in the U. S. are being designed to operate in compliance with the HWC MACT standards. Activities have been underway for the past 10 years at the INL and elsewhere to identify, develop, demonstrate, and design technologies for enabling HWC MACT compliance for mixed waste treatment facilities. Some specific off-gas …
Date: September 1, 2005
Creator: Soelberg, Nick
System: The UNT Digital Library
ADVANCED TECHNOLOGIES FOR THE SIMULTANEOUS SEPARATION OF CESIUM AND STRONTIUM FROM SPENT NUCLEAR FUEL (open access)

ADVANCED TECHNOLOGIES FOR THE SIMULTANEOUS SEPARATION OF CESIUM AND STRONTIUM FROM SPENT NUCLEAR FUEL

Two new solvent extraction technologies have been recently developed to simultaneously separate cesium and strontium from spent nuclear fuel, following dissolution in nitric acid. The first process utilizes a solvent consisting of chlorinated cobalt dicarbollide and polyethylene glycol extractants in a phenyltrifluoromethyl sulfone diluent. Recent improvements to the process include development of a new, non-nitroaromatic diluent and development of new stripping reagents, including a regenerable strip reagent that can be recovered and recycled. This new strip reagent reduces product volume by a factor of 20, over the baseline process. Countercurrent flowsheet tests on simulated spent nuclear fuel feed streams have been performed with both cesium and strontium removal efficiencies of greater than 99 %. The second process developed to simultaneously separate cesium and strontium from spent nuclear fuel is based on two highly-specific extractants: 4',4',(5')-Di-(t-butyldicyclo-hexano)-18-crown-6 (DtBuCH18C6) and Calix[4]arene-bis-(tert-octylbenzo-crown-6) (BOBCalixC6). The DtBuCH18C6 extractant is selective for strontium and the BOBCalixC6 extractant is selective for cesium. A solvent composition has been developed that enables both elements to be removed together and, in fact, a synergistic effect was observed with strontium distributions in the combined solvent that are much higher that in the strontium extraction (SREX) process. Initial laboratory test results of the …
Date: February 1, 2005
Creator: Law, Jack D.; Todd, Terry A.; Herbst, R. Scott; Meikrantz, David H.; Peterman, Dean R.; Riddle, Catherine L. et al.
System: The UNT Digital Library