Engineering Commons^™

Dynamics Modeling Of Molten Salt Reactors, Visura Umesh Pathirana

Doctoral Dissertations

The abundance of energy is a necessity for the prosperity of humans. The rise in energy demand has created energy shortages and issues related to energy security. Nuclear energy can produce vast amounts of reliable energy without many of the negative externalities associated with other competing energy sources, such as coal and natural gas. As a result, public interest in nuclear power has increased in the past decade. Many new types of nuclear reactor are proposed. These nuclear reactor designs feature many passive technologies that can operate without external influence. Reactors that feature advanced passive safety features are catagorized as …

Multiphysics Assessment Of Accident Tolerant Fuel, Cladding, And Core Structural Material Concepts, Jacob Preston Gorton

Doctoral Dissertations

The severe accident at the Fukushima-Daiichi nuclear power plant in 2011 ignited a global research and development effort to replace traditionally-used materials in Light Water Reactors (LWRs) with Accident Tolerant Fuel (ATF) materials. These materials are intended to extend the coping time of nuclear power plants during severe accident scenarios, but must undergo thorough safety and performance evaluations before being implemented. Four ATF concepts are analyzed in this dissertation using state-of-the-art computer modeling tools: (1) iron-chromium-aluminum (FeCrAl) fuel rod cladding, (2) silicon carbide (SiC) fiber-reinforced, SiC matrix composite (SiC/SiC) boiling water reactor (BWR) channel boxes, (3) mixed thorium mononitride (ThN) …

Deterministic Neutron Transport And Multiphysics Experimental Safety Analyses At The High Flux Isotope Reactor, Christopher James Hurt

Doctoral Dissertations

The computational ability to accurately predict the conditions in an experiment under irradiation is a valuable tool in the operation of a research reactor whose scientific mission includes isotope production, materials irradiation, and neutron activation analysis. Understanding of different governing physics is required to ascertain satisfactory conditions within the experiment: the neutron transport behavior throughout the reactor and the coupled behavior of heat transfer, structural mechanics and fluid flow. Computational methods and tools were developed for robust numerical analysis of experiment behavior at the Oak Ridge National Laboratory (ORNL) High Flux Isotope Reactor (HFIR), including fully-coupled thermo-mechanics in three plutonium-238 …

Semi-Implicit Direct Kinetics Methodology For Deterministic, Time-Dependent, Three-Dimensional, And Fine-Energy Neutron Transport Solutions, James Ernest Banfield

Doctoral Dissertations

Using a semi-implicit direct kinetics (SIDK) method that is developed in this dissertation, a finer neutron energy discretization and improved fidelity for transient radiation transport calculations are facilitated to reduce uncertainties and conservatisms in transient power and temperature predictions. These capabilities are implemented within a parallel computational solver framework, which is able to represent an arbitrary number of neutron energy groups, angles, and spatial discretizations, while internally coupled to an unstructured finite element multi-physics code for temperature and displacement calculations. This capability is demonstrated on a three-dimensional control rod ejection simulation run in parallel utilizing forty-four neutron energy groups.

An …