Thermal Spectrum

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C. D. Bowman - One of the best experts on this subject based on the ideXlab platform.

  • Once-Through Thermal-Spectrum Accelerator-Driven Light Water Reactor Waste Destruction Without Reprocessing
    Nuclear Technology, 2000
    Co-Authors: C. D. Bowman
    Abstract:

    An accelerator-driven Thermal-Spectrum liquid-fueled system is described for transmutation of spent fuel from commercial power reactors. The primary purpose of the system is to destroy the weapons-useful plutonium and neptunium in commercial spent fuel and thereby eliminate international concerns about the recovery of such material from geologic repositories for nuclear weapons purposes. The system also extracts ~80% of the fission energy available in the plutonium, and this energy is converted into electricity and sold into the commercial grid to pay nearly all of the capital and operating costs. The 20% of the material not destroyed is converted to an isotopic composition of no interest from a weapons perspective. These functions are accomplished without recycling or separation of a stream of pure plutonium. With technological development enabling widespread deployment in the 2015 to 2025 time frame, the world’s inventory of nuclear weapons useful material could be reduced by a factor of 100 or more by ...

  • accelerator driven systems for nuclear waste transmutation
    Annual Review of Nuclear and Particle Science, 1998
    Co-Authors: C. D. Bowman
    Abstract:

    The renewed interest since 1990 in accelerator-driven subcritical systems for transmutation of commercial nuclear waste has evolved to focus on the issue of whether fast- or Thermal-Spectrum systems offer greater promise. This review addresses the issue by comparing the performance of the more completely developed Thermal- and fast-Spectrum designs. Substantial design information is included to allow an assessment of the viability of the systems compared. The performance criteria considered most important are (a) the rapidity of reduction of the current inventory of plutonium and minor actinide from commercial spent fuel, (b) the cost, and (c) the complexity. The liquid-fueled Thermal Spectrum appears to offer major advantages over the solid-fueled fast-Spectrum system, making waste reduction possible with about half the capital requirement on a substantially shorter time scale and with smaller separations requirements.

  • Optimization of accelerator-driven technology for LWR waste transmutation
    1996
    Co-Authors: C. D. Bowman
    Abstract:

    The role of accelerator-driven transmutation technology is examined in the context of the destruction of actinide waste from commercial light water reactors. It is pointed out that the commercial plutonium is much easier to use for entry-level nuclear weapons than weapons plutonium. Since commercial plutonium is easier to use, since there is very much more of it already, and since it is growing rapidly, the permanent disposition of commercial plutonium is an issue of greater importance than weapons plutonium. The minor actinides inventory, which may be influenced by transmutation, is compared in terms of nuclear properties with commercial and weapons plutonium and for possible utility as weapons material. Fast and Thermal Spectrum systems are compared as means for destruction of plutonium and the minor actinides. it is shown that the equilibrium fast Spectrum actinide inventory is about 100 times larger than for Thermal Spectrum systems, and that there is about 100 times more weapons-usable material in the fast Spectrum system inventory compared to the Thermal Spectrum system. Finally it is shown that the accelerator size for transmutation can be substantially reduced by design which uses the accelerator-produced neutrons only to initiate the unsustained fission chains characteristic of the subcritical system. The analysis argues for devoting primary attention to the development of Thermal Spectrum transmutation technology. A Thermal Spectrum transmuter operating at a fission power of 750-MWth fission power, which is sufficient to destroy the actinide waste from one 3,000-MWth light water reactor, may be driven by a proton beam of 1 GeV energy and a current of 7 mA. This accelerator is within the range of realizable cyclotron technology and is also near the size contemplated for the next generation spallation neutron source under consideration by the US, Europe, and Japan.

  • Accelerator-driven Thermal Spectrum system for weapons plutonium destruction
    Transactions of the American Nuclear Society, 1993
    Co-Authors: C. D. Bowman, F. Venneri
    Abstract:

    In examining how best to destroy weapons-grade plutonium by fission, several objectives can be considered: (1) Destroy it as quickly as possible. (2) Derive the maximum economic benefit from this unique material built up at great expense. (3) Use its [open quotes]hot[close quotes] neutronic properties to assist in the destruction of plutonium and higher actinides from commercial spent fuel. (4) Leave the minimum long-term high-level waste from the fission destruction process. This paper is directed at the societal benefits possible if the first objective were laid aside. The Los Alamos National Laboratory (LANL) has been studying for several years accelerator-driven systems for the dual objectives of economically generating nuclear energy while concurrently transmuting the long-lived resulting waste and destroying existing commercial nuclear waste with minimal economic cost. In addition to the attractive subcriticality feature that the accelerator provides, it also supplements the neutron economy of the system so that sufficient neutrons are available to transmute the objectionable waste. The weapons-grade plutonium, or highly enriched [sup 235]U for that matter, can enhance the neutron economy as well with the result that the requirement for supplementary neutrons from the accelerator for the transmutation process can be reduced.

Toshihiro Matsuo - One of the best experts on this subject based on the ideXlab platform.

  • Massless radiation from heavy rotating string and Kerr/string correspondence
    Nuclear Physics B, 2010
    Co-Authors: Toshihiro Matsuo
    Abstract:

    We calculate emission rates of a massless state from a highly excited rotating string in perturbative bosonic open string theory. By averaging huge degeneracies of initial string states with specifying the mass and a single component of the angular momentum, we find Thermal Spectrum in a wide range of the angular momentum. We derive the temperature that characterizes the Thermal Spectrum from the partition function of a single rotating string from which we also find the entropy and the angular velocity of rotating strings. We also argue based on these quantities the Horowitz-Polchinski correspondence principle between rotating strings/Kerr black holes for non-extremal as well as extremal cases. In the parameter region where the Kerr black holes exist, the Thermal Spectrum is comparable to scalar emissions from a rotating black hole.Comment: 21 pages, minor corrections, version to appear in Nucl.Phys.

  • Massless radiation from heavy rotating string and Kerr/string correspondence
    Nuclear Physics, 2009
    Co-Authors: Toshihiro Matsuo
    Abstract:

    Abstract We calculate emission rates of a massless state from a highly excited rotating string in perturbative bosonic open string theory. By averaging huge degeneracies of initial string states with specifying the mass and a single component of the angular momentum, we find Thermal Spectrum in a wide range of the angular momentum. We derive the temperature that characterizes the Thermal Spectrum from the partition function of a single rotating string from which we also find the entropy and the angular velocity of rotating strings. We also argue based on these quantities the Horowitz–Polchinski correspondence principle between rotating strings/Kerr black holes for non-extremal as well as extremal cases. In the parameter region where the Kerr black holes exist, the Thermal Spectrum is comparable to scalar emissions from a rotating black hole.

Xing-chang Song - One of the best experts on this subject based on the ideXlab platform.

Hong-zhi Chen - One of the best experts on this subject based on the ideXlab platform.

Debraj Roy - One of the best experts on this subject based on the ideXlab platform.

  • The Unruh Thermal Spectrum through scalar and fermion tunneling
    Physics Letters B, 2009
    Co-Authors: Debraj Roy
    Abstract:

    Abstract The Thermal Spectrum seen by accelerated observers in Minkowski space vacuum, the Unruh effect, is derived within the tunneling mechanism. This is a new result in this mechanism and it completes the treatment of Unruh effect via tunneling. Both Bose–Einstein and Fermi–Dirac Spectrum is derived by considering tunneling of scalar and spin half particles respectively, across the accelerated Rindler horizon. Full solutions of massless Klein–Gordon and Dirac equations in the Rindler metric are employed to achieve this, instead of approximate solutions.

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