Physical Sciences and Mathematics Commons^™

Use Of Electrochemical Techniques And Statistical Analysis To Investigate The Pitting Probability Of Copper, Sina Matin

Electronic Thesis and Dissertation Repository

The development of a safe permanent disposal plan is essential for the long-term disposal of used fuel bundles. Nuclear Waste Management Organization (NWMO) has been investigating the deep geologic disposal of nuclear waste which offers the optimum passive safety system with a negligible probability of release of radionuclides into the environment.

The proposed used fuel containers (UFC) for the permanent disposal of high-level nuclear waste in Canada is comprised of a carbon steel vessel coated with a 3 mm corrosion-resistant copper layer deposited using a combination of electrodeposition and cold spray deposition. Although copper is often considered to be thermodynamically …

Characterization Of Deposited Copper Oxide Films On Copper Substrates, Millicent Castillo

Electronic Thesis and Dissertation Repository

The deposition of copper oxide films on copper substrates was investigated by the electrochemical, thermal, and hydrothermal oxidation of copper. The formed oxides were characterized using various surface analytical techniques to determine the film’s morphology, composition, and thickness. The results show that by growing oxides electrochemically, a duplex layer composing of CuO and Cu₂O film was formed on the copper surface, having characteristics of being porous and possessing needle-like structures. An oxide film composed of CuO and Cu₂O, which shows minimal porosity and possess mixtures of crystalline and non-crystalline structures, is formed on the copper surface …

Analysis And Differentiation Of Uniform And Localized Corrosion Of Cu, Roshan J. Daljeet

Electronic Thesis and Dissertation Repository

The current plan for disposal of used nuclear fuel in Canada involves sealing the waste in steel containers coated with 3 mm of copper and burying them in a deep geologic repository (DGR). The purpose of the copper coating is to provide corrosion resistance. To achieve long term containment, it is necessary that the copper layer corrodes slowly and predictably via active dissolution rather than passivating due to film formation. Film formation could allow pitting corrosion to occur in early phase repository conditions when groundwater ions such as Cl– , SO4 2– and HCO3 – play a dominant role in …

Investigating The Corrosion Behaviour Of Ni-Based Alloys In Industrially Relevant Environments, Jeffrey D. Henderson

Electronic Thesis and Dissertation Repository

Typical engineering materials may experience high corrosion rates when exposed to aggressive service conditions. Such conditions include high concentrations of aggressive anions and oxidants, high solution acidity, and/or high temperatures. Alloys with high corrosion resistance may be selected to avoid material failure caused by corrosion, for example, Ni-Cr-Mo alloys. These alloys exhibit excellent corrosion resistance due to the formation of a passive oxide film, primarily containing Cr and Mo. However, film breakdown can result in localized corrosion, e.g., crevice corrosion. Localized corrosion processes can penetrate deep into the bulk alloy, threatening its integrity. While the oxide film and localized …

Synthesis Of Stable Organic Radical Homo- And Co-Polymers And Their Applications In Solid-State Devices, Michael Anghel

Electronic Thesis and Dissertation Repository

This thesis outlines the synthesis and characterization of a stable organic radical homopolymer incorporating nitronyl nitroxide radicals, as well as the synthesis and characterization of random and block co-polymers incorporating nitronyl nitroxide and 6-oxoverdazyl radicals.

The nitronyl nitroxide homopolymer was synthesized using ring-opening metathesis polymerization (ROMP), yielding polymers with controlled molecular weights and narrow molecular weight distributions. Studies of polymer growth as a function of time and monomer:catalyst ratio revealed the ROMP to be well-behaved. Spectroscopic analysis of the polymer showed that the radicals possessed high radical content, indicating that they are tolerated by ROMP. Conductivity studies of thin-films made …

Galvanic Corrosion Of Carbon Steel-Stainless Steel Welds, Mi Li

Electronic Thesis and Dissertation Repository

A water leak in one of the Canada Deuterium Uranium (CANDU) nuclear reactors could lead to galvanic corrosion between the materials of its supporting structures: carbon steel (CS) and stainless steel (SS). This project investigates the effects of physical and chemical solution parameters on the corrosion of galvanically coupled dissimilar CS-SS welds, with the aim of developing a corrosion dynamics model that can be used to assess the long-term integrity of the CANDU reactor structural materials with confidence. The studied parameters were solution pH, temperature, the presence or absence of γ-radiation and the cathode:anode surface area ratio. Multiple electrochemical techniques …

The Influence Of Radiolytically Produced Nitric Acid On The Corrosion Resistance Of Copper-Coated Used Nuclear Fuel Containers, Joseph P. Turnbull

Electronic Thesis and Dissertation Repository

In Canada, the proposed disposal method for high level nuclear waste involves sealing the waste in steel containers with a 3 mm outer copper coating and burying it in a deep geologic repository. However, the thickness of the container is significantly reduced making a reassessment of the influence of γ-radiation, emitted by the waste form, on container corrosion a potential licensing requirement. Under humid aerated conditions, the formation of nitric acid is expected, potentially resulting in the formation of droplets or wetted layers on the container surface. Currently available literature on the corrosion of copper in nitric acid does not …

Electrochemical Investigation Into The External Failure Modes Of Oil And Gas Pipelines, Maxwell Goldman

Electronic Thesis and Dissertation Repository

Carbon steel is the material of choice for transmission pipelines for the oil and gas industry across the globe due to its mechanical properties, and low cost. Carbon steel is only resistffxidant, and the types of anions present in the exposure environment. Transmission pipelines are coated with non-conductive polymeric coatings and can be protected by cathodic protection in order to mitigate exterior corrosion. The primary goals of this thesis were to determine the role of anions, cathodic charging with hydrogen, and steel microstructure on different failure modes of carbon steel.

The corrosion mechanism of carbon steel in the presence of …

Synthesis, Characterization, And Applications Of Group 13 And 14 Complexes Of Chelating Formazanate Ligands, Ryan R. Maar

Electronic Thesis and Dissertation Repository

This thesis describes the synthesis and characterization of group 13 (boron and aluminum) and group 14 (silicon, germanium, and tin) complexes supported by chelating formazanate [R¹-N-N=C(R³)-N=N-R⁵]^‒ ligands. The resulting complexes are redox-active and often luminescent. Chapters two to four describe the synthesis and characterization of boron formazanate adducts. The work in these chapters demonstrates that through structural modification of the formazanate ligand, solid-state- and NIR photoluminescence can be achieved. Furthermore, the formation of an oxoborane (B=O) afforded a highly photoluminescent formazanate adduct due to the structural rigidity imposed by the B=O bond. These …

Corrosion Studies On Lightweight Automotive Alloys: The Effect Of Microstructure And Fundamental Mechanisms, Wilfred J. Binns

Electronic Thesis and Dissertation Repository

Owing to their excellent strength-to-weight ratio and low density, magnesium alloys have the potential to significantly reduce the weight of automobiles leading to decreased emissions and greater range for electrical vehicles. However, the practicality of magnesium alloys for automotive and aerospace applications is severely hindered by their poor corrosion resistance in aqueous environments. Despite intensive research effort, the underlying mechanism(s) responsible for this poor corrosion resistance remains elusive. Further complicating the situation is the presence of secondary microstructures which are necessary for desirable physical properties but lead to microgalvanic coupling which exacerbates the poor corrosion resistance of magnesium alloys. This …

Corrosion Dynamics Of Carbon Steel In Used Fuel Container Environments, Dan Guo

Electronic Thesis and Dissertation Repository

The current Canadian used nuclear fuel container (UFC) design uses a pressure‑grade carbon steel (CS) vessel with its outer surface coated with a thin layer of copper. One concern regarding the structural integrity of the UFC design is the potential internal corrosion of the CS vessel. Moisture trapped inside a UFC could condense within the gap between the hemispherical head and the cylindrical body of the vessel. The internal UFC environment will be exposed to a continuous flux of ionizing radiation arising from the decay of radionuclides trapped in the used UO₂ fuel matrix.

This thesis research project investigates …

The Electrochemical Study Of Simulated Spent Nuclear Fuel (Simfuel) Corrosion Under Permanent Disposal Conditions, Ziyan Zhu

Electronic Thesis and Dissertation Repository

The safety assessment of spent nuclear fuel under permanent disposal conditions requires examination of the corrosion of the spent fuel waste form (UO₂) inside a failed waste container. The objective of this research project was to develop a detailed mechanism of the UO₂ corrosion process when exposed to groundwater. The redox conditions within a failed container in a deep geologic repository will be complex. The oxidant, H₂O₂, produced by the α-radiolysis of groundwater, will be the main driving force for fuel corrosion. However, the efficiency of fuel dissolution will be determined by the …

Electrochemical And Corrosion Examination Of Copper Under Deep Geologic Conditions For The Application Of Nuclear Waste Containers, Taylor L. Martino

Electronic Thesis and Dissertation Repository

Copper is the selected material for the fabrication of nuclear fuel waste containers in Sweden, Finland and Canada due to its corrosion resistance in the anoxic aqueous environments, anticipated in deep geological repositories. A potential oxidant for copper is bisulphide produced either by the dissolution of minerals or by sulphate-reducing bacteria. The primary goals of this thesis were to determine the mechanism of corrosion of copper in bisulphide environments and to investigate the chemistry of the bentonite porewater that will ultimately be in contact with the copper container.

The mechanism of sulphide film growth and the details of copper corrosion …

Electrochemical And Modelling Studies On Simulated Spent Nuclear Fuel Corrosion Under Permanent Waste Disposal Conditions, Nazhen Liu

Electronic Thesis and Dissertation Repository

The safety assessment models for the deep geological disposal of spent nuclear fuel require a fundamental understanding of the corrosion of spent fuel in a failed waste container. The overall research goal of this project is to investigate the corrosion of simulated spent fuel under permanent disposal conditions, using both model simulations and experimental investigations. A model for fuel corrosion has been expanded to determine the relative importance of radiolytic hydrogen and hydrogen from corrosion of the steel vessel in suppressing fuel corrosion. It was shown that, for CANDU (CANada Deuterium Uranium) fuel with moderate in-reactor burnup, only micromolar concentrations …

Synthesis Of Metal-Containing Polymers And Stable Organic Radical-Containing Polymers And Their Use As Advanced Functional Materials, Joseph A. Paquette

Electronic Thesis and Dissertation Repository

The work presented in this thesis details the synthesis and characterization of two different families of multifunctional polymers. The first family involved the incorporation of stable 6-oxoverdazyl radicals into polymer scaffolds. This was originally achieved by the polymerization of the radical precursors, phenyl- and isopropyl-6-oxotetrazanes, followed by post-polymerization oxidation to afford the phenyl- and isopropyl-6-oxoverdazyl polymers. A second methodology involved the direct polymerization of isopropyl-6-oxoverdazyl radicals using ring-opening metathesis polymerization (ROMP) to afford polymers with controlled molecular weights and narrow molecular weight distributions. The polymers were characterized by the close comparison of the physical and spectroscopic properties …

The Corrosion Of Carbon Steel Under Deep Geologic Nuclear Waste Disposal Conditions, Shannon L.W. Hill

Electronic Thesis and Dissertation Repository

The proposed disposal scenario for high-level nuclear waste (spent fuel) in Canada is emplacement within a sealed, deep geological repository (DGR) located in either granitic rock or sedimentary clay. Disposal is based on a multi-barrier approach, with the primary barrier being a sealed container which could be either dual-walled with a copper shell over an inner carbon steel vessel for granitic rock or a single thick-walled steel container for sedimentary clay. This study focuses on the corrosion behaviour of A516 Gr70 carbon steel as well as the corrosion products formed in a variety of groundwater compositions and concentrations expected within …

Electrogenerated Chemiluminescence Of Gold Nanoclusters, Mahdi Hesari

Electronic Thesis and Dissertation Repository

A series of monodispersed AuNCs including Au144(SR)60, Au38(SR)24 and Au25(SR)18z (z =1-, 0 and 1+, SR=2-phenylethanethiol) were prepared. All these nanoclusters showed molecule-like optical and electrochemical properties. These two features are essential for an electrogenerated chemiluminescence or electrochemiluminescence (ECL) study. The Au144(SR)60 showed a small HOMO-LUMO gap determined by electrochemistry. No ECL light was seen in the annihilation process, while NIR ECL was observed with tri-n- propylamine (TPrA) (Chapter 2). ECL was highly efficient in the Au38(SR)24/TPrA co- reactant system. This nanocluster also showed ECL emission with benzoyl peroxide (BPO), while no ECL was detected in the annihilation route (Chapter …

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 …

Electrochemiluminescence Of Thienyltriazoles, Iridium Complexes, Au25 Clusters And Pbs Nanoparticles, Kalen N. Swanick

Electronic Thesis and Dissertation Repository

Electrogenerated chemiluminescence or electrochemiluminescence (ECL), produces light in the vicinity of a working electrode by the excited species of a luminophore formed via electron transfer between radical cations and anions, which are electrogenerated. In order for the ECL system to be efficient, the radicals must be stable in solution. This can be enhanced by adding co-reactants such as benzoyl peroxide (BPO) and tri-n-propylamine (TPrA) that produce strong oxidizing or reducing radicals upon redox reactions. ECL pairs electrochemical and spectroscopic methods and is a powerful analytical technique that is highly sensitive and selective.

A comprehensive, mechanistic study of ECL …

The Effect Of The Environment On The Corrosion Products And Corrosion Rates On Gas Transmission Pipelines, Brent Sherar

Electronic Thesis and Dissertation Repository

This thesis reports a series of investigations examining external corrosion processes along gas transmission pipelines. TransCanada PipeLines Ltd. (TCPL) has developed six proposed corrosion scenarios to describe external pipeline corrosion, based primarily on corrosion products and corrosion rates (CRs) observed at field sites. The six proposed corrosion scenarios can be divided into two groups: abiotic and biotic. The three abiotic corrosion scenarios are (1) anaerobic corrosion, (2) aerobic corrosion, and (3) anaerobic corrosion turning aerobic; while (4) anaerobic corrosion with microbial effects, (5) aerobic corrosion turning anaerobic with microbial effects, and (6) anaerobic corrosion with microbial effects turning aerobic comprise …