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Catalyzed Water Oxidation by Solar Irradiation of Band-Gap-Narrowed Semiconductors (Part 2. Overview).

Description: The objectives of this report are: (1) Investigate the catalysis of water oxidation by cobalt and manganese hydrous oxides immobilized on titania or silica nanoparticles, and dinuclear metal complexes with quinonoid ligands in order to develop a better understanding of the critical water oxidation chemistry, and rationally search for improved catalysts. (2) Optimize the light-harvesting and charge-separation abilities of stable semiconductors including both a focused effort to improve the best … more
Date: March 18, 2008
Creator: Fujita, E.; Khalifah, P.; Lymar, S.; Muckerman, J. T. & Rodriguez, J.
Partner: UNT Libraries Government Documents Department
open access

REVERSIBLE CONVERSION BETWEEN CHEMICAL AND ELECTRICAL ENERGIES CATALYZED BY Ru COMPLEXES AIMED TO CONSTRUCT SUSTAINABLE SOCIETY.

Description: The present study demonstrates that [Ru{sup II}(NH{sub 3})(q)(trpy)]{sup +} has an ability to oxidize alcohols catalytically under very mild conditions under electrolysis at +0.35 V in MeOH. The elucidation of the reaction mechanisms in the alcohol-oxidation is underway.
Date: November 30, 2007
Creator: TANAKA,K.; WADA, T.; FUJITA, E. & MUCKERMAN, J.
Partner: UNT Libraries Government Documents Department
open access

PHOTOCHEMICAL CO2 REDUCTION BY RHENUIM AND RUTHENIUM COMPLEXES.

Description: Photochemical conversion of CO{sub 2} to fuels or useful chemicals using renewable solar energy is an attractive solution to both the world's need for fuels and the reduction of greenhouse gases. Rhenium(I) and ruthenium(II) diimine complexes have been shown to act as photocatalysts and/or electrocatalysts for CO{sub 2} reduction to CO. We have studied these photochemical systems focusing on the identification of intermediates and the bond formation/cleavage reactions between the metal center a… more
Date: November 30, 2007
Creator: FUJITA,E.; MUCKERMAN, J.T. & TANAKA, K.
Partner: UNT Libraries Government Documents Department
open access

Catalyzed Water Oxidation by Solar Irradiation of Band-Gap-Narrowed Semiconductors (Part 1. Overview).

Description: The objectives of this report are: (1) Investigate the catalysis of water oxidation by cobalt and manganese hydrous oxides immobilized on titania or silica nanoparticles, and dinuclear metal complexes with quinonoid ligands in order to develop a better understanding of the critical water oxidation chemistry, and rationally search for improved catalysts. (2) Optimize the light-harvesting and charge-separation abilities of stable semiconductors including both a focused effort to improve the best … more
Date: March 18, 2008
Creator: Fujita, E.; Khalifah, P.; Lymar, S.; Muckerman, J. T. & Rodgriguez, J.
Partner: UNT Libraries Government Documents Department
open access

Fuel management studies of small metal and oxide LMR's

Description: Fuel-cycle analyses performed at Argonne National Laboratory to evaluate and compare the neutronic performance characteristics of small oxide- and metal-fueled LMR's are described. Specific consideration is given to those analyses concerned with optimization of core and blanket configurations, selection of fuel residence time and refueling interval, determination of control rod worths and requirements, development of in-core fuel management strategy, and evaluation of performance characteristic… more
Date: January 1, 1986
Creator: Khalil, H.; Fujita, E. K.; Yang, S. & Orechwa, Y.
Partner: UNT Libraries Government Documents Department
open access

Trends vs. reactor size of passive reactivity shutdown and control performance

Description: For LMR concepts, the goal of passive reactivity shutdown has been approached in the US by designing the reactors for favorable relationships among the power, power/flow, and inlet temperature coefficients of reactivity, for high internal conversion ratio (yielding small burnup control swing), and for a primary pump coastdown time appropriately matched to the delayed neutron hold back of power decay upon negative reactivity input. The use of sodium bonded metallic fuel pins has facilitated the … more
Date: January 1, 1987
Creator: Wade, D. C. & Fujita, E. K.
Partner: UNT Libraries Government Documents Department
open access

Core concepts for zero-sodium-void-worth core'' in metal fuelled fast reactor

Description: Core design options to reduce the sodium void worth in metal fueled LMRs are investigated. Two core designs which achieve a zero sodium void worth are analyzed in detail. The first design is a pancaked'' and annular core with enhanced transuranic burning capabilities; the high leakage in this design yields a low breeding ratio and small void worth. The second design is an axially multilayered annular core which is fissile self-sufficient; in this design, the upper and lower core regions are neu… more
Date: January 1, 1991
Creator: Chang, Y. I.; Hill, R. N.; Fujita, E. K.; Wade, D. C. (Argonne National Lab., IL (United States)); Kumaoka, Y.; Suzuki, M. et al.
Partner: UNT Libraries Government Documents Department
open access

Comparative neutronic analysis of Pb-versus Na-cooled LMR cores

Description: A comparative neutronic study has been conducted on several LMR cores using both lead-magnesium eutectic alloy (97.7% Pb -- 2.3% Mg) and sodium as coolant. In order to have a consistent comparison for these two coolants on a common basis, i.e. interchangeable designs, this study used exactly the same reactor core layout, assembly design parameters, and compositions for structure material. Only driver fuel enrichments were adjusted respectively for these two coolants in order to meet the same se… more
Date: January 1, 1992
Creator: Liaw, J. R.; Fujita, E. K. & Wade, D. C.
Partner: UNT Libraries Government Documents Department
open access

Core design and performance of small inherently safe LMRs

Description: Oxide and metal-fueled core designs at the 900 MWt level and constrained by a requirement for interchangeability are described. The physics parameters of the two cores studied here indicate that metal-fueled cores display attractive economic and safety features and are more flexible than are oxide cores in adapting to currently-changing deployment scenarios.
Date: January 1, 1986
Creator: Orechwa, Y.; Khalil, H.; Turski, R. B. & Fujita, E. K.
Partner: UNT Libraries Government Documents Department
open access

Trends vs. reactor size of passive reactivity shutdown and control performance

Description: The focus of the US advanced reactor program since the cancellation of CRBR has been on inherent safety and cost reduction. The notion is to so design the reactor that in the event of an off normal condition, it brings itself to a safe shutdown condition and removes decay heat by reliance on ''inherent processes'' i.e., without reliance on devices requiring switching and outside sources of power. Such a reactor design would offer the potential to eliminate costly ''Engineered Safety Features,''… more
Date: January 1, 1988
Creator: Wade, D. C. & Fujita, E. K.
Partner: UNT Libraries Government Documents Department
open access

Physics considerations in the design of liquid metal reactors for transuranium element consumption

Description: The management of transuranic nuclides in liquid metal reactors (LMR's) is considered based on the use of the Integral Fast Reactor (IFR) concept. Unique features of the IFR fuel cycle with respect to transuranic management are identified. These features are exploited together with the hard spectrum of LMR's to demonstrate the neutronic feasibility of a wide range of transuranic management options ranging from efficient breeding to pure consumption. Core physics aspects of the development of a … more
Date: January 1, 1992
Creator: Khalil, H.; Hill, R.; Fujita, E. & Wade, D.
Partner: UNT Libraries Government Documents Department
open access

Comparative neutronic analysis of Pb-versus Na-cooled LMR cores

Description: A comparative neutronic study has been conducted on several LMR cores using both lead-magnesium eutectic alloy (97.7% Pb -- 2.3% Mg) and sodium as coolant. In order to have a consistent comparison for these two coolants on a common basis, i.e. interchangeable designs, this study used exactly the same reactor core layout, assembly design parameters, and compositions for structure material. Only driver fuel enrichments were adjusted respectively for these two coolants in order to meet the same se… more
Date: February 1, 1992
Creator: Liaw, J. R.; Fujita, E. K. & Wade, D. C.
Partner: UNT Libraries Government Documents Department
open access

Binding of carbon dioxide to metal macrocycles: Toward a mechanistic understanding of electrochemical and photochemical carbon dioxide reduction

Description: Efforts were made to find effective catalysts for photochemical and electrochemical reduction of CO[sub 2]. We are studying the factors controlling excited-state lifetimes, electron-transfer rates to mediators/catalysts, properties of reduced mediators, binding of small molecules to reduced mediators, and reactivity of the mediators to yield the desired products. This document describes some of the results of binding on CO[sub 2] to metal macrocycles. The electrocatalytic activity of cobalt mac… more
Date: January 1, 1993
Creator: Fujita, E.
Partner: UNT Libraries Government Documents Department
open access

Physics studies of weapons plutonium disposition in the IFR closed fuel cycle

Description: The core performance impact of weapons plutonium introduction into the IFR closed fuel cycle is investigated by comparing three disposition scenarios: a power production mode, a moderate destruction mode, and a maximum destruction mode all at a constant heat rating of 840 MWt. For each scenario, two fuel cycle models are evaluated: cores using weapons material as the sole source of transuranics in a once-through mode, and recycle corns using weapons material only as required for a make-up feed.… more
Date: March 1, 1994
Creator: Hill, R. N.; Wade, D. C.; Liaw, J. R. & Fujita, E. K.
Partner: UNT Libraries Government Documents Department
open access

Binding of carbon dioxide to metal macrocycles: Toward a mechanistic understanding of electrochemical and photochemical carbon dioxide reduction

Description: Efforts were made to find effective catalysts for photochemical and electrochemical reduction of CO{sub 2}. We are studying the factors controlling excited-state lifetimes, electron-transfer rates to mediators/catalysts, properties of reduced mediators, binding of small molecules to reduced mediators, and reactivity of the mediators to yield the desired products. This document describes some of the results of binding on CO{sub 2} to metal macrocycles. The electrocatalytic activity of cobalt mac… more
Date: July 1, 1993
Creator: Fujita, E.
Partner: UNT Libraries Government Documents Department
open access

Toward Photochemical Water Splitting Using Band-Gap-Narrowed Semiconductors and Transition-Metal Based Molecular Catalysts

Description: We are carrying out coordinated theoretical and experimental studies of toward photochemical water splitting using band-gap-narrowed semiconductors (BGNSCs) with attached multi-electron molecular water oxidation and hydrogen production catalysts. We focus on the coupling between the materials properties and the H{sub 2}O redox chemistry, with an emphasis on attaining a fundamental understanding of the individual elementary steps in the following four processes: (1) Light-harvesting and charge-s… more
Date: June 7, 2009
Creator: Muckerman, J. T.; Rodriguez, J. A. & Fujita, E.
Partner: UNT Libraries Government Documents Department
open access

Photogeneration of Hydride Donors and Their Use Toward CO2 Reduction

Description: Despite substantial effort, no one has succeeded in efficiently producing methanol from CO2 using homogeneous photocatalytic systems. We are pursuing reaction schemes based on a sequence of hydride-ion transfers to carry out stepwise reduction of CO2 to methanol. We are using hydride-ion transfer from photoproduced C-H bonds in metal complexes with bio-inspired ligands (i.e., NADH-like ligands) that are known to store one proton and two electrons.
Date: June 7, 2009
Creator: Fujita, E.; Muckerman, J. T. & Polyansky, D. E.
Partner: UNT Libraries Government Documents Department
open access

Physics studies of higher actinide consumption in an LMR

Description: The core physics aspects of the transuranic burning potential of the Integral Fast Reactor (IFR) are assessed. The actinide behavior in fissile self-sufficient IFR closed cycles of 1200 MWt size is characterized, and the transuranic isotopics and risk potential of the working inventory are compared to those from a once-through LWR. The core neutronic performance effects of rare-earth impurities present in the recycled fuel are addressed. Fuel cycle strategies for burning transuranics from an ex… more
Date: January 1, 1990
Creator: Hill, R. N.; Wade, D. C.; Fujita, E. K. & Khalil, H. S.
Partner: UNT Libraries Government Documents Department
open access

XAS studies of Ni(I), Ni(II), and Ni(III) complexes

Description: XAS techniques for studying structural and electronic changes taking place during oxidation and reduction reactions of nickel complexes are described and applied to selected models for Factor 430, a nickel containing cofactor catalyzing an important step in the conversion of carbon dioxide to methane by methanogenic bacteria.
Date: January 1, 1995
Creator: Furenlid, L. R.; Renner, M. W. & Fujita, E.
Partner: UNT Libraries Government Documents Department
open access

Criticality safety evaluation of the fuel cycle facility electrorefiner

Description: The integral Fast Reactor (IFR) being developed by Argonne National Laboratory (ANL) combines the advantages of metal-fueled, liquid-metal cooled reactors and a closed-loop fuel cycle. Some of the primary advantages are passive safety for the reactor and resistance to diversion for the heavy metal in the fuel cycle. in addition, the IFR pyroprocess recycles all the long-lived actinide activation products for casting into new fuel pins so that they may be burned in the reactor. A key component i… more
Date: September 1, 1993
Creator: Lell, R. M.; Mariani, R. D.; Fujita, E. K.; Benedict, R. W. & Turski, R. B.
Partner: UNT Libraries Government Documents Department
open access

Physics considerations in the design of liquid metal reactors for transuranium element consumption

Description: The management of transuranic nuclides in liquid metal reactors (LMR`s) is considered based on the use of the Integral Fast Reactor (IFR) concept. Unique features of the IFR fuel cycle with respect to transuranic management are identified. These features are exploited together with the hard spectrum of LMR`s to demonstrate the neutronic feasibility of a wide range of transuranic management options ranging from efficient breeding to pure consumption. Core physics aspects of the development of a … more
Date: September 1, 1992
Creator: Khalil, H.; Hill, R.; Fujita, E. & Wade, D.
Partner: UNT Libraries Government Documents Department
open access

Criticality safety strategy for the Fuel Cycle Facility electrorefiner at Argonne National Laboratory, West

Description: The Integral Fast Reactor being developed by Argonne National Laboratory (ANL) combines the advantages of metal-fueled, liquid-metal-cooled reactors and a closed fuel cycle. Presently, the Fuel Cycle Facility (FCF) at ANL-West in Idaho Falls, Idaho is being modified to recycle spent metallic fuel from Experimental Breeder Reactor II as part of a demonstration project sponsored by the Department of Energy. A key component of the FCF is the electrorefiner (ER) in which the actinides are separated… more
Date: September 1, 1993
Creator: Mariani, R. D.; Benedict, R. W.; Lell, R. M.; Turski, R. B. & Fujita, E. K.
Partner: UNT Libraries Government Documents Department
open access

CARBON DIOXIDE AS A FEEDSTOCK.

Description: This report is an overview on the subject of carbon dioxide as a starting material for organic syntheses of potential commercial interest and the utilization of carbon dioxide as a substrate for fuel production. It draws extensively on literature sources, particularly on the report of a 1999 Workshop on the subject of catalysis in carbon dioxide utilization, but with emphasis on systems of most interest to us. Atmospheric carbon dioxide is an abundant (750 billion tons in atmosphere), but dilut… more
Date: December 9, 2000
Creator: CREUTZ,C. & FUJITA,E.
Partner: UNT Libraries Government Documents Department
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