Texas A&M University LibrariesTexas A&M University LibrariesTexas A&M University Libraries
    • Help
    • Login
    OAKTrust
    View Item 
    •   OAKTrust Home
    • Colleges and Schools
    • Office of Graduate and Professional Studies
    • Electronic Theses, Dissertations, and Records of Study (2002– )
    • View Item
    •   OAKTrust Home
    • Colleges and Schools
    • Office of Graduate and Professional Studies
    • Electronic Theses, Dissertations, and Records of Study (2002– )
    • View Item
    JavaScript is disabled for your browser. Some features of this site may not work without it.

    Nuclear Forensics Methodology for Source Reactor-Type Discrimination of Chemically Separated Plutonium

    Thumbnail
    View/ Open
    OSBORN-DISSERTATION-2018.pdf (2.883Mb)
    Date
    2018-08-16
    Author
    Osborn, Jeremy Michael
    Metadata
    Show full item record
    Abstract
    The growing nuclear threat has heightened the need for developing nuclear forensics analysis techniques that contribute to nuclear material source attribution, thereby strengthening nuclear deterrence. The objective of this research was to develop a nuclear forensics methodology that is capable of source reactor-type discrimination of chemically separated weapons-usable plutonium. The developed methodology utilizes plutonium and fission product intra-element isotope ratios within the plutonium sample to predict characteristics of the irradiated material, including burnup, time since irradiation, and reactor type. The MCNPX-2.7 and MCNP6 radiation transport codes were used to model reactor cores, perform burnup simulations, and estimate the isotopics of the discharged fuel. Ratios of intra-element isotopes (fission products and plutonium) were identified which contribute to resolving the parameters of burnup, time since irradiation, and reactor type. The simulation results were used to generate a reactor-dependent library of intra-element isotope ratio values as a function of burnup and time since irradiation. A maximum likelihood calculation was utilized to compare the simulated intra-element isotope ratio values contained in the reactor library to the same ratio values measured in the sample. The result is a likelihood value which is proportional to the probability of observing the measured intra-element isotope ratios given the reactor type and parameters. In order to validate the nuclear forensics methodology developed, two experimental irradiation campaigns were performed, resulting in two distinct UO₂ fuel samples containing weapons-usable plutonium. The first was designed to replicate weapons-usable plutonium produced in the blanket of a fast breeder reactor, by irradiating depleted UO₂ fuel samples in a pseudo-fast neutron spectrum within the High Flux Isotope Reactor at Oak Ridge National Laboratory. The second irradiation was designed to represent weapons-usable plutonium produced in a natural uranium fueled thermal reactor, by irradiating natural UO₂ fuel samples in a thermal neutron spectrum at the University of Missouri Research Reactor. The irradiated samples were subjected to nondestructive and destructive analyses to measure the plutonium and fission product isotope ratios. The methodology performed well for both experimentally irradiated cases, identifying the source reactor model and adequately predicting the burnup and time since irradiation. The work presented here served to develop and validate a nuclear forensics source reactor-type discrimination methodology.
    URI
    https://hdl.handle.net/1969.1/174417
    Subject
    Nuclear forensics
    weapons-grade plutonium
    discrimination methodology
    maximum likelihood
    experimental validation
    Collections
    • Electronic Theses, Dissertations, and Records of Study (2002– )
    Citation
    Osborn, Jeremy Michael (2018). Nuclear Forensics Methodology for Source Reactor-Type Discrimination of Chemically Separated Plutonium. Doctoral dissertation, Texas A & M University. Available electronically from https : / /hdl .handle .net /1969 .1 /174417.

    DSpace software copyright © 2002-2016  DuraSpace
    Contact Us | Send Feedback
    Theme by 
    Atmire NV
     

     

    Advanced Search

    Browse

    All of OAKTrustCommunities & CollectionsBy Issue DateAuthorsTitlesSubjectsDepartmentTypeThis CollectionBy Issue DateAuthorsTitlesSubjectsDepartmentType

    My Account

    LoginRegister

    Statistics

    View Usage Statistics
    Help and Documentation

    DSpace software copyright © 2002-2016  DuraSpace
    Contact Us | Send Feedback
    Theme by 
    Atmire NV