Engineering Commons^™

Examination Of Experimental Data For Irradiation-Induced Creep In Nuclear Graphite, Amir Sassan Mobasheran

Doctoral Dissertations

The objective of this dissertation was to establish credibility and confidence levels of the observed behavior of nuclear graphite in neutron irradiation environment. Available experimental data associated with the OC-series irradiation-induced creep experiments performed at the Oak Ridge National Laboratory (ORNL) were examined.

Pre- and postirradiation measurement data were studied considering "linear" and "nonlinear" creep models. The nonlinear creep model considers the creep coefficient to vary with neutron fluence due to the densification of graphite with neutron irradiation. Within the range of neutron fluence involved (up to 0.53 x 10²⁶ neutrons/m², E > 50 KeV), both models were …

Dynamic Modeling Of A Pressurized Water Reactor Plant For Diagnostics And Control, Masoud Naghedolfeizi

Masters Theses

A nonlinear model, based on lumped parameter approach, has been developed for computer simulation of a typical Westinghouse Pressurized Water Reactor (PWR) system. The model predicts dynamic behavior of system variables under steady-state and transient conditions. Nonlinear simulation has been applied to study the control systems of the PWR plant. This includes the design of proper actuator and control systems for reactor, steam generator, pressurizer, and turbine models. This model has also been used to identify the responses of plant variables to anomalies in the PWR subsystems at 85% power.

Linear models of the PWR primary loop components have been …

A High Performance Detector Electronics System For Positron Tomography, John Clifton Moyers, Jr.

Masters Theses

Positron Emission Tomography (PET) has been a very useful laboratory tool for the noninvasive study of dynamic physiological processes within the human body. Its clinical worth in cardiology, neurology, and oncology has been verified for well over a decade. Only with the most recent introduction of high performance analog and VLSI digital components yielding higher scanner resolutions at reduced costs, has clinical PET truly become a reality. The High Performance Detector Electronics System presented here represents indubitably the most advanced processing system available in the clinical PET market.

Quiescent And Oriented Crystallization Behavior Of Linear Low Density Polyethylenes, Lawrence S. Hood

Masters Theses

A series of isothermal and non-isothermal crystallization experiments were performed on nine linear low density polyethylenes and one high density polyethylene. In addition, melt spinning experiments were performed on three linear low density polyethylenes in order to gain a better understanding of their spinline behavior and the effect of stress on their crystallization behavior.

Isothermal experiments showed that crystallization rates were dependent on branching of the polymer molecules. Resins with extensive branching had crystallization rates which were much lower than linear polyethylene. This behavior was also observed in non-isothermal crystallization experiments.

Half time analysis was performed on the isothermal data …

Development Of The High Vacuum Steady-State Orbitron Maser, Mark S. Rader

Masters Theses

The Orbitron MASER is a device which can be used to generate R.F. radiation. This device has been operated for many years as a gas filled pulsed device. This thesis describes a brief history, design and operation of several steady-state, hot cathode Orbitron MASER. It also touches on a pulsed Orbitron MASER and the effects the hot cathode has on the radial electric field profile. A detailed derivation of emission frequency, gain and saturation is given in Appendix.