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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
191

Characterization of a Stochastic Procedure for the Generation and Transport of Fission Fragments within Nuclear Fuels

Hackemack, Michael Wayne 03 October 2013 (has links)
With the ever-increasing demands of the nuclear power community to extend fuel cycles and overall core-lifetimes in a safe and economic manner, it is becoming more necessary to extend the working knowledge of nuclear fuel performance. From the atomistic to the macroscopic level, great morphological changes occur within the fuel over its lifetime. The main initial damaging events produced by fuel recoils from fast neutrons and fission fragment spiking leads to the onset of grain growths and fuel restructuring. Therefore, it is desirable to have a more detailed understanding of the initial events leading to fuel morphology changes at the atomistic level. However, this is difficult to achieve with the fission fragments due to the wide variability of their species (charge, mass, and energy) and the large averaging of their relative yields in the nuclear data files. This work is our first iteration at developing a general methodology to characterize a procedure, based on Monte Carlo principles, for generating individual fission event result channels and analyzing their specific response in the fuel. We utilized the nuclear reaction simulation tool, TALYS, to generate energy-dependent fission fragment yield distributions for different fissile/fissionable isotopes. These distributions can then be used in conjunction with fuel isotopics and a neutron energy spectrum to generate a fission-reaction-rate-averaged distribution of the fission fragment yields. We then used Monte Carlo sampling to generate the result channels from individual fission events, using the Q-value of the prompt fission system to either accept or reject. The simulation tool: Transport of Ions in Matter (TRIM) was used to characterize the general response of the fission fragment species within Uranium Dioxide (UO2), including the range, energy loss, displacements, recoils, etc. These responses were then correlated which allowed for the quick calculation of the response of the individual fission fragment species generated from the Monte Carlo sampling. As an example of this strategy, we calculated the response on a PWR fuel pin where MCNP was used to generate a high-fidelity neutron energy spectrum.
192

Coil Design and Related Studies for the Fusion-Fission Reactor Concept SFLM Hybrid

Hagnestål, Anders January 2012 (has links)
A fusion-fission (hybrid) reactor is a combination of a fusion device and a subcritical fission reactor, where the fusion device acts as a neutron source and the power is mainly produced in the fission core. Hybrid reactors may be suitable for transmutation of transuranic isotopes in the spent nuclear fuel, due to the safety margin on criticality imposed by the subcritical fission core. The SFLM Hybrid project is a theoretical project that aims to point out the possibilities with steady-state mirror-based hybrid reactors. The quadrupolar magnetic mirror vacuum field is based on the Straight Field Line Mirror field and the central cell is 25 m long. A fission mantle surrounds the mirror cell. The fission to fusion power ratio is about 150 with keff = 0.97, implying that almost all the produced energy comes from fission. Beyond each mirror end magnetic expanders are located, which increase the plasma receiving “divertor” area and provide tolerable heat load on wall materials. The plasma is heated with ion cyclotron radio frequency heating and the fission mantle is cooled using a liquid lead-bismuth eutectic. The device is self-sufficient in tritium, and does not seem to suffer from severe material problems. A remaining issue may be the plasma electron temperature, which need to reach about 500 eV for efficient power production.  In this doctoral thesis, theoretical work has been done with the magnetic coil system of such a device and also with the overall concept. A new coil type, the fishbone coil, suitable for single cell quadrupolar mirrors, has been invented. Two vacuum field coil sets with satisfying properties have been found, where the most recent coil set consists of fishbone coils. Finite ß effects on the magnetic field have been investigated, showing that the flux tube ellipticity increases with ß. The ellipticity of the vacuum field increases slightly with radius, but with finite ß it decreases with radius. The maximum flux surface radial extensions decrease with ß, which is an unexpected and beneficial result. A radial invariant has also been identified, and particle simulations have been made to emphasize that quadrupolar mirrors must be symmetric or confinement may be lost.
193

Studies of prompt gamma and neutron yield due to 2.5 MeV neutrons using GEANT4

Tovar, Jesus Felipe, January 2009 (has links)
Thesis (M.S.)--University of Texas at El Paso, 2009. / Title from title screen. Vita. CD-ROM. Includes bibliographical references. Also available online.
194

Radioactive gaseous effluents from the core of the AGN-201 reactor at the United States Naval Postgraduate School

Bredderman, Rudolf Theodore Andrew. January 1966 (has links) (PDF)
Thesis (M.S. in Physics)--Naval Postgraduate School, May 1966. / Thesis Advisor(s): Riggin, John D. "May 1966." Description based on title screen as viewed on June 2, 2010. DTIC Descriptor(s): Reactor Cores, Gases, Fission Products, Gases, Gamma Ray Spectra, Radioactive Isotopes, Krypton, Xenon. DTIC Identifier(s): AGN-201 Reactors. Author(s) subject terms: Reactor Gas, Xenon Gamma Spectrum, Krypton Gamma Spectrum. Includes bibliographical references (p. 36). Also available in print.
195

Angular distributions from heavy-ion-induced fission

Viola, V. E. January 1961 (has links)
Thesis--University of California, Berkeley, 1961. / "UC-4 Physics" -t.p. "TID-4500 (16th Ed.)" -t.p. Includes bibliographical references (p. 88-91).
196

High-energy induced fission theory and application

Hart, Robert R. January 1955 (has links)
Thesis (M.S. in Physics)--United States Naval Postgraduate School, California. / "Unclassified Physics." Includes bibliographical references (p. 36). 14
197

Fission and spallation excitation functions of U²³⁸

Ritseman, Susanne Elaine. January 1956 (has links)
Thesis (Master's)--University of California, Berkeley. / Includes bibliographical references (p. 33-35). 54
198

Analise de transmutacao considerando o tratamento explicito dos produtos de fissao num sistema acoplado, composto pelos codigos Hammer-Technion e

ABE, ALFREDO Y. 09 October 2014 (has links)
Made available in DSpace on 2014-10-09T12:36:18Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T13:59:17Z (GMT). No. of bitstreams: 1 03980.pdf: 2316245 bytes, checksum: 417b388f4f1b84fef2568b5807e84716 (MD5) / Dissertacao (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP
199

Aplicação dos métodos radioquímico e de espectrometria de raios gama direto para determinação da queima do óxido de urânio irradiado

CUNHA, IEDA I.L. 09 October 2014 (has links)
Made available in DSpace on 2014-10-09T12:50:44Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T13:59:01Z (GMT). No. of bitstreams: 1 00489.pdf: 2163294 bytes, checksum: 196f74ff6ebe12447bea84e82e4ebc7f (MD5) / Dissertacao (Mestrado) / IEA/D / Instituto de Quimica, Universidade de Sao Paulo - IQ/USP
200

Aufbau der systeme Mo-Ru-Rh-Pd und UO2-ZrO2-MoO2-BaO und ihre Korrelation mit spaltproduktausscheidungen in bestrahlten brennstoffen

PASCHOAL, JOSE O.A. 09 October 2014 (has links)
Made available in DSpace on 2014-10-09T12:31:30Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T13:59:33Z (GMT). No. of bitstreams: 1 01417.pdf: 15560137 bytes, checksum: 857fe87504571bc27557a261974b6971 (MD5) / Tese (Doutoramento) / IPEN/T / Universitaet Karlsruhe - Fakultaet fuer Maschinenbau

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