Physical Sciences and Mathematics Commons^™

Effect Of Gamma Radiation On The Interfacial Reactions And Transfer Processes Of Phosphonium-Based Ionic Liquids With Carbon Steel, Ryan P. Morco

Electronic Thesis and Dissertation Repository

This thesis presents work on the effects of ionizing radiation on phosphonium-based ionic liquids (ILs). Ionic liquids are known for their tunable properties which make them attractive options for applications for the separation and sequestration of metal ions from spent nuclear fuels, and candidate lubricants for systems under severe conditions. The high radiation environment found in spent fuel processing may decompose the solvents (ILs) used in the process and affect their separation efficiency. The radiolytic decomposition products can also alter the physical and chemical properties of an IL in ways which can affect the potential corrosion of metal alloys in …

Radiation Induced Corrosion Of Stellite-6, Mehran Behazin

Electronic Thesis and Dissertation Repository

This thesis presents a study on the aqueous corrosion of a cobalt-based alloy, Stellite-6. Since aqueous corrosion kinetics are strongly influenced by water chemistry conditions (pH, temperature, and redox agents), a systematic study of Stellite-6 corrosion was carried out. The aim was to develop an ability to predict corrosion behaviour and particularly metal dissolution rates for cobalt alloys under a range of conditions. The work focused on a study of the influence of ionizing radiation on corrosion. This is of particular interest in the nuclear industry where radiation fields are present. Ionizing radiation creates oxidizing radiolysis products and alters the …

Gamma-Radiolysis Kinetics Of Liquid, Vapour And Supercritical Water, Nastaran Yousefi

Electronic Thesis and Dissertation Repository

Inadequate understanding of radiation-induced water chemistry under supercritical conditions has been identified as one of the important obstacles in the development of a supercritical water-cooled reactor. Radiolysis of supercritical water generates a variety of redox reactive species, but their persistence in supercritical water is not well understood. This thesis describes the work performed towards addressing this deficiency: (1) the development of a reliable experimental method to determine the concentrations of water radiolysis products, primarily H₂, O₂ and H₂O₂, formed under g-irradiation of sub- and supercritical water (SCW), (2) the expansion of the application …

Tip-Enhances Raman Spectroscopy, Enabling Spectroscopy At The Nanoscale, Nastaran Kazemi Zanjani

Electronic Thesis and Dissertation Repository

The knowledge on the chemical and the structural properties of substances benefits strongly from characterization methods that can provide access to the sample’s nanoscale building blocks. Not only should the sensitivity of these methods approach a high detection limit up to single molecule, but also the accessible spatial resolution must enable chemical imaging of individual nanoscale features of the substances. High resolution imaging is often provided by electron microscopes through methods such as transmission electron microscopy (TEM) and scanning electron microscopy (STM), nevertheless, these methods lack offering chemical information. Surface-enhanced spectroscopy was developed to improve the sensitivity of the chemical …

The Electrochemistry Of Hydrogen Peroxide On Uranium Dioxide And The Modelling Of Used Nuclear Fuel Corrosion Under Permanent Disposal Conditions, Linda Wu

Electronic Thesis and Dissertation Repository

This thesis reports a series of investigations examining the corrosion process of used nuclear fuel under permanent disposal conditions. The motivation of the project is that the safety assessment of deep geological disposal of spent nuclear fuel requires a fundamental understanding of the processes controlling fuel corrosion which could lead to the release of radionuclides to the geosphere from a failed container.

One primary objective of this project was to develop a computational model in order to simulate fuel corrosion under the disposal conditions. A series of simulations based on COMSOL were designed and developed to determine the influence of …

A Molecular Simulation Study On Micelle Fragmentation And Wetting In Nano-Confined Channels, Mona Habibi

Electronic Thesis and Dissertation Repository

We performed coarse-grained molecular-dynamics (MD) simulations to study the structural and dynamical properties of surfactant micelles in equilibrium and under Poiseuille-like flow in a nano-confined geometry. We used the MARTINI force-field to model the interactions between water molecules, counter-ions, and sodium dodecyl sulfate (SDS) surfactants. SDS surfactant was chosen as the standard model because of its potential application in drug delivery systems. First, we focused on the self-assembly of SDS in equilibrium. To form stable spherical mi- celles, we ran simulations in the isothermal-isobaric ensemble (NPT) on a system of free SDS surfactants, counter-ions and water molecules. We studied the …