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L.c. Brown - One of the best experts on this subject based on the ideXlab platform.

  • Direct Energy Conversion FISSION REACTOR ANNUAL REPORT FOR THE PERIOD OCTOBER 1, 2001 THROUGH DECEMBER 31, 2002
    2003
    Co-Authors: L.c. Brown
    Abstract:

    OAK-B135 Direct Energy Conversion FISSION REACTOR ANNUAL REPORT FOR THE PERIOD OCTOBER 1, 2001 THROUGH DECEMBER 31, 2002

  • Magnetically insulated fission electric cells for Direct Energy Conversion
    Physics of Plasmas, 2003
    Co-Authors: S. A. Slutz, David B. Seidel, R. J. Lipinski, G. E. Rochau, L.c. Brown
    Abstract:

    The principles of fission electric cells are reviewed. A detailed Monte Carlo model of the efficiency of a fission electric cell is presented and a theory of magnetically insulated fission electric cells (MIFECs) is developed. It is shown that the low operating voltages observed in previous MIFEC experiments were due to nonoptimal magnetic field profiles. Improved magnetic field profiles are presented. It is further shown that the large electric field present in a MIFEC limits the structure of the cathode and can lead to a displacement instability of the cathode toward the anode. This instability places constraints on the number of cells that can be strung together without some external cathode support. The large electric field stress also leads to electrical surface breakdown of the cathode. It is shown that this leads to the formation of a virtual cathode resulting in geometry constraints for spherical cells. Finally it is shown that the requirements of magnetic insulation and high efficiency leads to very low average density of the fissile material. Thus a reactor using fission electric cells for efficient Direct Energy Conversion will be large and require a very large number of cells. This could be mitigated somewhat by the use of exotic fuels.

  • Direct Energy Conversion FISSION REACTOR FOR THE PERIOD JANUARY 1, 2002 THROUGH MARCH 31, 2002
    2002
    Co-Authors: L.c. Brown
    Abstract:

    Direct Energy Conversion is the only potential means for producing electrical Energy from a fission reactor without the Carnot efficiency limitations. This project was undertaken by Sandia National Laboratories, Los Alamos National Laboratories, The University of Florida, Texas A&M University and General Atomics to explore the possibilities of Direct Energy Conversion. Other means of producing electrical Energy from a fission reactor, without any moving parts, are also within the statement of proposed work. This report documents the efforts of General Atomics. Sandia National Laboratories, the lead laboratory, provides overall project reporting and documentation. The highlights of this reporting period are: (1) Cooling of the vapor core reactor and the MHD generator was incorporated into the Vapor Core Reactor model using standard heat transfer calculation methods. (2) Fission product removal, previously modeled as independent systems for each class of fission product, was incorporated into the overall fuel recycle loop of the Vapor Core Reactor. The model showed that the circulating activity levels are quite low. (3) Material distribution calculations were made for the ''pom-pom'' style cathode for the Fission Electric Cell. Use of a pom-pom cathode will eliminate the problem of hoop stress in the thin spherical cathode caused by the electric field.

  • Direct Energy Conversion in fission reactors: A U.S. NERI project
    2000
    Co-Authors: Stephen A. Slutz, Gary F. Polansky, David B. Seidel, S. Anghaie, L.c. Brown, Gary E Rochau, Ronald J. Lipinski, G. Besenbruch, T.a. Parish, D.e. Beller
    Abstract:

    In principle, the Energy released by a fission can be converted Directly into electricity by using the charged fission fragments. The first theoretical treatment of Direct Energy Conversion (DEC) appeared in the literature in 1957. Experiments were conducted over the next ten years, which identified a number of problem areas. Research declined by the late 1960's due to technical challenges that limited performance. Under the Nuclear Energy Research Initiative the authors are determining if these technical challenges can be overcome with todays technology. The authors present the basic principles of DEC reactors, review previous research, discuss problem areas in detail, and identify technological developments of the last 30 years that can overcome these obstacles. As an example, the fission electric cell must be insulated to avoid electrons crossing the cell. This insulation could be provided by a magnetic field as attempted in the early experiments. However, from work on magnetically insulated ion diodes they know how to significantly improve the field geometry. Finally, a prognosis for future development of DEC reactors will be presented .

Lloyd C. Brown - One of the best experts on this subject based on the ideXlab platform.

Motoo Ishikawa - One of the best experts on this subject based on the ideXlab platform.

  • Recent Results in Research on Direct Energy Conversion for a Fusion System
    Fusion Science and Technology, 2013
    Co-Authors: Hiromasa Takeno, Yasuyoshi Yasaka, Motoo Ishikawa, Y. Nakashima, M. Kume, N. Sotani, Y. Munakata, S. Harada, D. Akashi, T. Kawaguchi
    Abstract:

    Recent results in research on Direct Energy Conversion are presented and discussed comprehensively. As for conventional devices, present subjects and the status of researches are explained for devices of cusp and traveling wave types and for those used commercially. Newly proposed devices are also introduced with their background and initial evaluation.

  • experiment on Direct Energy Conversion from tandem mirror plasmas by using a slanted cusp magnetic field
    Nuclear Fusion, 2008
    Co-Authors: Yasuyoshi Yasaka, Hiromasa Takeno, Y. Kurumatani, Y. Nakashima, T. Yamamoto, Teruji Cho, Yukihiro Tomita, Motoo Ishikawa
    Abstract:

    A Direct Energy converter (DEC) designed for thermal ions escaping from a linear or near-linear device consists of a cusp magnetic field and decelerating electrodes. The electrons are deflected along the field lines and consequently separated from ions that are not fully magnetized. The ions are led to the decelerating electrodes to produce dc power. This type of DEC, the CUSPDEC, is applied to the GAMMA 10 tandem mirror in order to investigate the capability of separation of charged particles as well as to demonstrate Energy Conversion from ions. The separation of electrons and ions with energies of the order of kilo-electron Volt is achieved by using a slanted cusp magnetic field for the first time. It is also demonstrated that the separated ions are decelerated by the electric field in front of ion collectors and flow into the collectors at a high potential to produce electricity.

  • Direct Energy Conversion experiment on the GAMMA 10 tandem mirror
    Fusion Science and Technology, 2007
    Co-Authors: Yasuyoshi Yasaka, Hiromasa Takeno, Y. Kurumatani, Y. Nakashima, T. Yamamoto, Yuta Higashizono, M. Hirata, Teruji Cho, Yukihiro Tomita, Motoo Ishikawa
    Abstract:

    A Direct Energy converter (DEC) designed for thermal ions escaping from a fusion reactor consists of a cusp magnetic field and one or two stage decelerating electrodes. The electrons are deflected along the field lines and consequently separated from thermal ions that are not fully magnetized. The ions are led to the electrodes to produce DC power. For basic investigation of this type of DEC, the CUSPDEC, a small-scale experimental device is constructed and its characteristics have been investigated by using a low-Energy plasma source. In this paper, the device is applied to the GAMMA 10 tandem mirror in order to investigate the capability of separation of charged particles as well as to demonstrate Energy Conversion from ions in much more reactor-relevant environment. The separation of electrons and ions with energies of the order of keV is achieved by using a slanted cusp magnetic field for the first time. It is also found that the separated ions are decelerated by the electric field in front of ion collectors and flow into the collectors at a high potential to produce DC power.

  • Particle Discrimination Experiment for Direct Energy Conversion
    Fusion Science and Technology, 2005
    Co-Authors: Yasuyoshi Yasaka, Yuusuke Kiriyama, S. Yamamoto, Hiromasa Takeno, Motoo Ishikawa
    Abstract:

    A Direct Energy Conversion system designed for D- 3 He fusion reactor based on afield reversed configuration employs a venetian-blind type converter for thermal ions to produce DC power and a traveling wave type converter for fusion protons to produce RF power. It is therefore necessary to separate, discriminate, and guide the particle species. For this purpose, a cusp magnetic field is proposed, in which the electrons are deflected and guided along the field line to the line cusp, while the ions pass through the point cusp. A small-scale experimental device was used to study the basic characteristics of discrimination of electrons and ions in the cusp magnetic field. Ions separated from electrons are guided to an ion collector, which is operated as a one-stage Direct Energy converter. The Conversion efficiency was measured for cases with different values of mean and spread of ion Energy. These experiments successfully demonstrate Direct Energy Conversion from plasma beams using particle discrimination by a cusp magnetic field.

Yasuyoshi Yasaka - One of the best experts on this subject based on the ideXlab platform.

  • Recent Results in Research on Direct Energy Conversion for a Fusion System
    Fusion Science and Technology, 2013
    Co-Authors: Hiromasa Takeno, Yasuyoshi Yasaka, Motoo Ishikawa, Y. Nakashima, M. Kume, N. Sotani, Y. Munakata, S. Harada, D. Akashi, T. Kawaguchi
    Abstract:

    Recent results in research on Direct Energy Conversion are presented and discussed comprehensively. As for conventional devices, present subjects and the status of researches are explained for devices of cusp and traveling wave types and for those used commercially. Newly proposed devices are also introduced with their background and initial evaluation.

  • experiment on Direct Energy Conversion from tandem mirror plasmas by using a slanted cusp magnetic field
    Nuclear Fusion, 2008
    Co-Authors: Yasuyoshi Yasaka, Hiromasa Takeno, Y. Kurumatani, Y. Nakashima, T. Yamamoto, Teruji Cho, Yukihiro Tomita, Motoo Ishikawa
    Abstract:

    A Direct Energy converter (DEC) designed for thermal ions escaping from a linear or near-linear device consists of a cusp magnetic field and decelerating electrodes. The electrons are deflected along the field lines and consequently separated from ions that are not fully magnetized. The ions are led to the decelerating electrodes to produce dc power. This type of DEC, the CUSPDEC, is applied to the GAMMA 10 tandem mirror in order to investigate the capability of separation of charged particles as well as to demonstrate Energy Conversion from ions. The separation of electrons and ions with energies of the order of kilo-electron Volt is achieved by using a slanted cusp magnetic field for the first time. It is also demonstrated that the separated ions are decelerated by the electric field in front of ion collectors and flow into the collectors at a high potential to produce electricity.

  • Research on Characteristics of Particle Discrimination and Direct Energy Conversion for Cusp Direct Energy Converter
    Fusion Science and Technology, 2007
    Co-Authors: Y. Kurumatani, Yasuyoshi Yasaka, T. Tsujimoto, Hiromasa Takeno
    Abstract:

    In a D-3He fusion reactor, Direct Energy Conversion is expected, and discrimination of charged particles from each other is needed to produce electric power. The authors have performed simulation experiments for discrimination and Direct Energy Conversion in a CUSPDEC device with a slanted cusp magnetic field. This paper presents a scaling of particle discrimination with proposition of an appropriate scaling factor based on the consideration of the Stormer potential. Experimental results with the factor up to 0.7 for ions and 80 for electrons are presented. The paper also presents results of Direct Energy Conversion of ions in higher Energy region up to 5 keV. It is confirmed that the Conversion efficiency does not depend on averaged Energy, but depends on the broadness of Energy distribution function.

  • Direct Energy Conversion experiment on the GAMMA 10 tandem mirror
    Fusion Science and Technology, 2007
    Co-Authors: Yasuyoshi Yasaka, Hiromasa Takeno, Y. Kurumatani, Y. Nakashima, T. Yamamoto, Yuta Higashizono, M. Hirata, Teruji Cho, Yukihiro Tomita, Motoo Ishikawa
    Abstract:

    A Direct Energy converter (DEC) designed for thermal ions escaping from a fusion reactor consists of a cusp magnetic field and one or two stage decelerating electrodes. The electrons are deflected along the field lines and consequently separated from thermal ions that are not fully magnetized. The ions are led to the electrodes to produce DC power. For basic investigation of this type of DEC, the CUSPDEC, a small-scale experimental device is constructed and its characteristics have been investigated by using a low-Energy plasma source. In this paper, the device is applied to the GAMMA 10 tandem mirror in order to investigate the capability of separation of charged particles as well as to demonstrate Energy Conversion from ions in much more reactor-relevant environment. The separation of electrons and ions with energies of the order of keV is achieved by using a slanted cusp magnetic field for the first time. It is also found that the separated ions are decelerated by the electric field in front of ion collectors and flow into the collectors at a high potential to produce DC power.

  • Particle Discrimination Experiment for Direct Energy Conversion
    Fusion Science and Technology, 2005
    Co-Authors: Yasuyoshi Yasaka, Yuusuke Kiriyama, S. Yamamoto, Hiromasa Takeno, Motoo Ishikawa
    Abstract:

    A Direct Energy Conversion system designed for D- 3 He fusion reactor based on afield reversed configuration employs a venetian-blind type converter for thermal ions to produce DC power and a traveling wave type converter for fusion protons to produce RF power. It is therefore necessary to separate, discriminate, and guide the particle species. For this purpose, a cusp magnetic field is proposed, in which the electrons are deflected and guided along the field line to the line cusp, while the ions pass through the point cusp. A small-scale experimental device was used to study the basic characteristics of discrimination of electrons and ions in the cusp magnetic field. Ions separated from electrons are guided to an ion collector, which is operated as a one-stage Direct Energy converter. The Conversion efficiency was measured for cases with different values of mean and spread of ion Energy. These experiments successfully demonstrate Direct Energy Conversion from plasma beams using particle discrimination by a cusp magnetic field.

David B. Seidel - One of the best experts on this subject based on the ideXlab platform.

  • Magnetically insulated fission electric cells for Direct Energy Conversion
    Physics of Plasmas, 2003
    Co-Authors: S. A. Slutz, David B. Seidel, R. J. Lipinski, G. E. Rochau, L.c. Brown
    Abstract:

    The principles of fission electric cells are reviewed. A detailed Monte Carlo model of the efficiency of a fission electric cell is presented and a theory of magnetically insulated fission electric cells (MIFECs) is developed. It is shown that the low operating voltages observed in previous MIFEC experiments were due to nonoptimal magnetic field profiles. Improved magnetic field profiles are presented. It is further shown that the large electric field present in a MIFEC limits the structure of the cathode and can lead to a displacement instability of the cathode toward the anode. This instability places constraints on the number of cells that can be strung together without some external cathode support. The large electric field stress also leads to electrical surface breakdown of the cathode. It is shown that this leads to the formation of a virtual cathode resulting in geometry constraints for spherical cells. Finally it is shown that the requirements of magnetic insulation and high efficiency leads to very low average density of the fissile material. Thus a reactor using fission electric cells for efficient Direct Energy Conversion will be large and require a very large number of cells. This could be mitigated somewhat by the use of exotic fuels.

  • An Overview of the Direct Energy Conversion Power Production Program
    10th International Conference on Nuclear Engineering Volume 4, 2002
    Co-Authors: Gregory A. Rochau, J. Cash, Donald B. King, Charles W. Morrow, David B. Seidel, S. A. Slutz, S. Anghaie, B. M. Smith, L. Brown, Pavel V. Tsvetkov
    Abstract:

    The United States Department of Energy, Nuclear Energy Research Initiative (NERI) Direct Energy Conversion (DEC) project has as its goal the development of a Direct Energy Conversion process suitable for commercial development. We define Direct Energy Conversion as any fission process that returns usable Energy without an intermediate thermal process. Enough of the project has been completed, roughly two thirds, to indicate that a viable Direct Energy device is possible. This paper reports on the progress of the DEC project. Three concepts are under development: Fission Electric Cell using magnetic insulation, Magnetic Collimator using magnetic fields to Direct fission fragments to collectors, and Gas Vapor Core Reactor using magnetohydrodynamics to generate electrical current. Included in this paper area a short project description, an abbreviated summary of the work completed to date, a description of ongoing and future project activities, and a discussion of the potential for future research and development.Copyright © 2002 by ASME

  • Direct Energy Conversion in fission reactors: A U.S. NERI project
    2000
    Co-Authors: Stephen A. Slutz, Gary F. Polansky, David B. Seidel, S. Anghaie, L.c. Brown, Gary E Rochau, Ronald J. Lipinski, G. Besenbruch, T.a. Parish, D.e. Beller
    Abstract:

    In principle, the Energy released by a fission can be converted Directly into electricity by using the charged fission fragments. The first theoretical treatment of Direct Energy Conversion (DEC) appeared in the literature in 1957. Experiments were conducted over the next ten years, which identified a number of problem areas. Research declined by the late 1960's due to technical challenges that limited performance. Under the Nuclear Energy Research Initiative the authors are determining if these technical challenges can be overcome with todays technology. The authors present the basic principles of DEC reactors, review previous research, discuss problem areas in detail, and identify technological developments of the last 30 years that can overcome these obstacles. As an example, the fission electric cell must be insulated to avoid electrons crossing the cell. This insulation could be provided by a magnetic field as attempted in the early experiments. However, from work on magnetically insulated ion diodes they know how to significantly improve the field geometry. Finally, a prognosis for future development of DEC reactors will be presented .