SUBJECT: | Ph.D. Dissertation Defense |

BY: | Richard Hoffman |

TIME: | Thursday, November 10, 2016, 10:00 a.m. |

PLACE: | MRDC Building, 3515 |

TITLE: | Kinetic Monte Carlo Models of Nuclear Materials |

COMMITTEE: | Dr. Chaitanya Deo, Chair (NRE) Dr. David Mcdowell (ME) Dr. Bojan Petrovic (NRE) Dr. Hamid Garmestani (MSE) Dr. Yan Wang (ME) |

SUMMARY Three KMC models are created using the SPPARKS code in order to examine the behavior of materials related to nuclear applications on the mesoscale. In addition work is done to examine the input parameters used in these simulations and determine the sensitivity of these parameters on the outcome of the simulation. The first of the models examines the diffusive behavior of oxygen vacancies introduced into a fluorite lattice system such as Ceria or Uranium Dioxide through doping of aliovalent oxides. Inputs are derived using molecular statics simulations of the energy barriers required for diffusive jumps. These inputs are then used by the simulation to determine the diffusivity and ionic conductivity of the materials due to the movement of vacancies in the simulation. The second model examines the diffusive behavior of simple and complex defects in BCC iron in order to examine the relationship between KMC and similar mesoscale models in informing continuum level models that determine the microstructural behavior of materials commonly used in nuclear support roles. The third model is a Potts style model designed to examine the grain growth and long term behavior of Uranium fuels found in most commercial nuclear reactors. The model uses data from experiments to inform the parameters that drive the model function. |