Polymer electrolyte membrane (PEM) fuel cells have been viewed as promising power source candidates for transport, stationary, and portable applications due to their high efficiency and low emissions. The platinum is the most commonly used catalyst material for the oxygen reduction reaction (ORR) at the cathode of PEM fuel cells; however, the limited abundance and high cost of platinum hinder the large-scale commercialization of fuel cells. To overcome this limitation, it is necessary to enhance the catalyst utilization in order to improve the catalytic activity while decreasing or eliminating the use of platinum. The material on which the catalyst is supported is important for the high dispersion and narrow distribution of Pt nanoparticles as well as other non-precious metal active sites, and these characteristics are closely related to electrocatalytic activity of the catalysts. The support materials can influence the catalytic activity by interplaying with catalytic metals, and the durability of the catalyst is also greatly dependent on its support. A variety of support materials like carbons, oxides, carbides, and nitrides have been employed as supports materials for fuel cell catalysts, and much effort has been devoted to the synthesis of the novel carbon supports with large surface area and/or pore volume, including nanostructured carbons such as carbon nanotubes (CNTs), carbon nanofibers, and mesoporous carbon. These novel nanostructured carbon materials have achieved promising performance in terms of catalytic activity and durability. However, there is still enormous demand and potential for the catalysts to improve. In the first study, non-precious metal catalysts (NPMC) for the oxygen reduction reaction were synthesized by deposition of Fe/Co-Nx composite onto nanoporous carbon black with ethylenediamine (EDA) as nitrogen precursor. Two different nanoporous carbon supports, Ketjen Black EC300J (KJ300) and EC600JD (KJ600), were used as catalyst support for the non-precious catalysts. The results obtained from the optimized FeCo/EDA-carbon catalyst, using KJ600 as the support, showed improved onset, half-wave potentials and superior selectivity than that of the KJ300. Similarly, the catalyst showed good performance in the hydrogen-oxygen PEM fuel cell. At a cell voltage of 0.6 V the fuel cell managed to produce 0.37 A/cm2 with a maximum power density of 0.44 W/cm2. Fuel cell life test at a constant voltage of 0.40 V demonstrated promising stability up to 100 h. The X-ray photoelectron spectroscopy study indicated that pyridinic type nitrogen of the non-precious metal catalysts is critical for ORR catalytic activity and selectivity. These results suggest higher pore volume and surface area of carbon support could lead to higher nitrogen content providing more active sites for ORR and this type of catalyst has great potential used as a non-precious PEM fuel cell catalyst. In the second study, we report the development of a novel NPMC in acid electrolyte using pyrimidine-2,4,5,6-tetramine sulfuric acid hydrate (PTAm) as a nitrogen precursor and graphene nanosheets as catalyst supports. Graphene, consisting of a two-dimensional (2D) monolayer of graphitic carbon atoms, has been viewed as a promising candidate for the fuel cell catalyst support, due to its many intriguing properties such as high aspect ratios, large surface areas, rich electronic states, good electron transport, thermal/chemical stability and good mechanical properties. We investigate the effect of different pyrolysis temperatures on the catalysts’ ORR activity along with detailed surface analysis to provide insight regarding the nature of the ORR active surface moieties. This novel NPMC demonstrates promising electrocatalyst activity and durability superior to that of commercial catalyst for the ORR, rendering graphene nanosheets as a suitable replacement to traditional nanostructured carbon support materials. In the final study, we have developed Pt catalyst by combining the precious metal with nitrogen-doped activated graphene (N-AG) as the support. A transmission electron microscopy (TEM) image of the catalyst shows uniform size and distribution of platinum nanoparticles on a graphene layer. This novel catalyst demonstrates superior electrocatalyst activity and durability over Pt/XC72 catalyst for ORR under the studied conditions, rendering graphene as an ideal replacement to traditional nanostructured carbon support materials. In summary, several catalyst samples were made using novel nanostructured support materials to improve the ORR performance. Several recommendations for future work were suggested in the last section of this work to further apply the knowledge and understanding of nanostructured support materials to design a highly active, durable, and low-cost NPMCs and platinum catalysts.

This report is concerned with the question whether Accelerator mass spectrometry (AMS) is asuitable technique for measuring actinide inventory in spent nuclear fuel, and if it is better thanpresent techniques for these measurements. AMS is a kind of Mass spectrometry (MS) and has alot of applications where radio carbon dating is one of the most common. AMS has been used formaking measurements on actinides before but mostly from traces in bioassay that could have beenin contact with weapon plutonium, and in bioassay near enrichment plants and reprocessingplants. It is shown in this report that AMS is more sensitive in low level measurements than thecurrent technique for spent nuclear fuel. ICP-MS is the current technique in use for inventorymeasurements on nuclear fuel at Swedish Nuclear Fuel and Waste Management Company (SKB).ICP-MS is also a kind of MS technique which is well-tried for inventory measurements on spentnuclear fuel. The difference in sensitivity ranges in levels of magnitude depending on whichisotope that is interesting for measurements. The lower detection limits for AMS is about 105-107atoms which makes it possible to use samples from nuclear fuel that is in the order of 10-10-10-16gto achieve the lower detection limit. The recommendation from this report is to make studies ifAMS also is an economical and efficiently suitable technique for future use on the actinideinventory in spent nuclear fuel. / Denna rapport handlar om huruvida Accelerator masspektrometri (AMS) är en lämplig teknik förmätning av aktinidinventeriet i använt kärnbränsle. Rapporten går också igenom om AMS är bättreän nuvarande tekniker för dessa mätningar. AMS är en typ av masspektrometri (MS) och har enmängd användningsområden, kol-14 metoden är en av de vanligaste. AMS har också ofta använtsför att göra mätningar på aktinidinnehåll i biomassa som kan ha varit i kontakt medvapenplutonium, och i närheten av anrikningsanläggningar och upparbetningsanläggningar. Detvisas i rapporten att AMS är en mer känslig metod än de nuvarande teknikerna som används förmätningar på aktinidinventariet i använt kärnbränsle. ICP-MS är den aktuella teknik som användsför mätningar på aktinidinventariet i använt kärnbränsle vid Svenska Kärnbränslehantering AB(SKB). ICP-MS är också en typ av MS teknik. MS är väl beprövad för mätningar av inventariet påanvänt kärnbränsle. Skillnaden i känslighet varierar i flera storleksordningar beroende på vilkenisotop som är intressant för mätningarna. Den lägre detektionsgränsen för AMS är cirka 105-107atomer, vilket gör det möjligt att använda prover från kärnbränsle som är i storleksordningen 10-10-10-16g för att uppnå den lägre detektionsgränsen. Rekommendationen från denna rapport är attgöra undersökningar om AMS också är ekonomiskt lönsam och tillräckligt effektiv teknik förframtida bruk inom mätningar av aktinidinventariet i använt kärnbränsle.

Due to concerns about energy security, rising oil prices, and adverse effects of internal combustion engine vehicles on the environment, the automotive industry is quickly moving towards developing efficient “green” vehicles. Fuel cell-powered vehicles offer high efficiency and practically zero emissions. The main obstacles for widespread commercial production of fuel cell vehicles are high cost and short lifetime of fuel cell stacks, lack of a hydrogen infrastructure, and generation of hydrogen in an environmentally-friendly manner and its storage. Using actual fuel cells and actual vehicular loads in the study of fuel cell vehicular systems can be prohibitive due to cost (initial and running) and safety issues. It is very desirable to have a test station that emulates a vehicle with a high degree of accuracy and flexibility to alleviate cost and safety issues. This thesis proposes a design for a test station that emulates the drive train of a typical fuel cell-powered vehicle that is equipped with regenerative braking capability. As part of the test station, a fuel cell emulator is designed and validated through simulation based on the Nexa Fuel Cell power module manufactured by Ballard Power Systems. As another building block for the test station, a bi-directional controllable DC load is developed that can realize a given drive cycle for the scaled-down version of a given vehicle. The load allows simulation of regenerative braking capability. The performance of the load is validated through simulation. A DC-DC boost converter for controlling the fuel cell power, as well as an energy storage system for assisting the fuel cell in providing the required power during high-demand periods, are incorporated into the proposed test station. Simulation results are used to show that the test station is capable of simulating the real-life conditions experienced by actual fuel cell vehicles on the road. The test station, when realized by hardware, can be used for performing a wide range of studies on the drive train architecture and power management of fuel cell vehicles.

Metal air battery has captured the spotlight recently as a promising class of sustainable energy storage for the future energy systems. Metal air batteries offer many attractive features such as high energy density, environmental benignity, as well as ease of fuel storage and handling. In addition, wide range of selection towards different metals exists where different energy capacity can be achieved via careful selection of different metals. The most energy dense systems of metal-air battery include lithium-air, aluminum-air and zinc-air. Despite the choice of metal electrode, oxygen reduction (ORR) occurs on the air electrode and oxidation occurs on the metal electrode. The oxidation of metal electrode is a relatively facile reaction compared to the ORR on the air electrode, making latter the limiting factor of the battery system. The sluggish ORR kinetics greatly affects the power output, efficiency, and lifetime of the metal air battery. One solution to this problem is the use of active, affordable and stable catalyst to promote the rate of ORR. Currently, platinum nanoparticles supported on conductive carbon (Pt/C) are the best catalyst for ORR. However, the prohibitively high cost and scarcity of platinum raise critical issues regarding the economic feasibility and sustainability of platinum-based catalysts. Cost reduction via the use of novel technologies can be achieved by two approaches. The first approach is to reduce platinum loading in the catalyst formulation. Alternatively platinum can be completely eliminated from the catalyst composition. The aim of this work is to identify and synthesize alternative catalysts for ORR toward metal air battery applications without the use of platinum re other precious metals (i.e., palladium, silver and gold). Non-precious metal catalysts (NPMC) have received immense international attentions owing to the enormous efforts in pursuit of novel battery and fuel cell technologies. Different types of NPMC such as transition metal alloys, transition metal or mixed metal oxides, chalcogenides have been investigated as potential contenders to precious metal catalysts. However, the performance and stability of these catalysts are still inferior in comparison. Nitrogen-doped carbon materials (NCM) are an emerging class of catalyst exhibiting great potential towards ORR catalysis. In comparison to the metal oxides, MCM show improved electrical conductivity. Furthermore, NCM exhibit higher activity compared to chalcogenides and transition metal alloys. Additional benefits of NCM include the abundance of carbon source and environmental benignity. Typical NCM catalyst is composed of pyrolyzed transition metal macrocycles supported by high surface area carbon. These materials have demonstrated excellent activity and stability. However, the degradation of these catalysts often involves the destruction of active sites containing the transition metal centre. To further improve the durability and mass transport of NCM catalyst, a novel class of ORR catalyst based on nitrogen-doped carbon nanotubes (NCNT) is investigated in a series of studies. The initial investigation focuses on the synthesis of highly active NCNT using different carbon-nitrogen precursors. This study investigated the effect of using cyclic hydrocarbon (pyridine) and aliphatic hydrocarbon (ethylenediamine) towards the formation and activity of NCNT. The innate structure of the cyclic hydrocarbon promotes the formation of NCNT to provide higher product yield; however, the aliphatic hydrocarbon promotes the formation of surface defects where the nitrogen atoms can be incorporated to form active sites for ORR. As a result, a significant increase in the ORR activity of 180 mV in half-wave potential is achieved when EDA was used as carbon-nitrogen precursor. In addition, three times higher limiting current density was observed for the NCNT synthesized from ethylenediamine. Based on the conclusion where highly active NCNT was produced from aliphatic hydrocarbon, similar carbon-nitrogen precursors with varying carbon to nitrogen ratio in the molecular structure (ethylenediamine, 1, 3-diaminopropane, 1, 4-diaminobutane) were adapted for the synthesis of NCNT. The investigation led to the conclusion that higher nitrogen to carbon ratio in the molecular structure of the precursors benefits the formation of active NCNT for ORR catalysis. The origin of such phenomena can be correlated with the higher relative nitrogen content of the resultant NCNT synthesized from aliphatic carbon precursor that provided greater nitrogen to carbon ratio. As the final nitrogen content increased in the molecular structure, the half-wave potential of the resultant NCNT towards ORR catalysis was increased by 120 mV. The significant improvement hints the critical role of nitrogen content towards ORR catalysis. To further confirm the correlation between the nitrogen content and ORR activity, another approach was used to control the final nitrogen content in the resultant NCNT. In the third investigation, a carbon-nitrogen precursor (pyridine) was mixed with a carbon precursor (ethanol) to form an admixture. The relative proportion of the two components of the admixture was varied to produce NCNT with different nitrogen content. By adopting this methodology, potential effect of different carbon-nitrogen precursors on the formation of NCNT can be eliminated since the same precursors were used for NCNT synthesis. Based on the electrochemical evaluations, the nitrogen content can be positively correlated to ORR activity. Among the NCNT samples, 41% higher limiting current density was achieved for 0.7 at. % increase in overall nitrogen content. Furthermore, the selectivity of the NCNT catalyst with higher nitrogen content favours the production of water molecule—the favourable product in metal-air battery by 43%. ORR catalyst is an outer-sphere electron transfer reaction whereby the reactants interact with the surface of catalysts. Consequently, the surface structure can be a determining factor towards the ORR activity of the NCNT in addition to the nitrogen content. In the forth investigation, the surface structure of NCNT was tailored to differentiate the ORR activity of smooth and rugged surface while controlling the overall nitrogen content to be similar. NCNT having different surface structures but similar nitrogen content (approximately 2.7 to 2.9 at. %) were successfully synthesized using different synthesis catalysts. Comparison of the two NCNT catalysts showing different surface structure resulted in a 130 mV increased in half-wave potential favouring the NCNT with more rugged surface structure. This study provided insights to the potential effects of synthesis catalyst towards directing the surface structure and the ORR activity of NCNT. Through a series of studies, the important parameters affecting the ORR performance of NCNT were elucidated and the most active NCNT catalyst synthesized was used for testing in a prototype zinc-air battery. The fifth study evaluated the performance of NCNT catalyst in different concentrations of alkaline electrolyte and at different battery voltage. An increase in the electrolyte’s alkaline strength improved the battery performance to a certain degree until the increasing viscosity impeded the performance of the battery system. The zinc-air battery employing NCNT as ORR catalyst produced a maximum battery power density of 69.5 mWcm-2 in 6M potassium hydroxide. The fifth study illustrated the great potential of NCNT towards the ORR catalysis for metal-air batteries. In combination, the series of investigations presented in this document provide a comprehensive study of a novel material and its application towards ORR catalysis in metal air batteries. Specifically, this report provides insights into the fundamentals of NCNT synthesis; the origins of ORR activity and the optimal operating conditions of NCNT in a prototype zinc-air battery. The excellent performance of NCNT warrants further studies of this material in greater details, and the information presented in this document will create a basis for future investigations towards ORR catalysis.

Flax shives are a source of abundant biomass from renewable sources. They are considered to be environmentally benign and have a high-energy content for heating and generation of electricity, but only after being processed into pellets. Pelleting of the shives was done by using the single-pelleter and pilot-scale mill. The effect of grinding with screens of 2.4, 3.2, and 6.4 mm on unit density and durability was conducted with a completely randomized design using shives from Biofibre Industries Inc., Canora, SK. The central composite face-centered design with 3 levels of lower grade canola meal used as a binder (18, 21, and 24%), moisture content (8, 11, and 14% (w.b)), and hammer mill screen size (3.2, 4.8, and 6.4 mm) was used to determine the effects of these three factors on the properties of fuel pellets made from shives obtained from Biolin Research Inc., Saskatoon, SK. The initial moisture content of coarse flax shives from both sources was about 10.5% wet basis (w.b.). The moisture content of flax shive grinds ranged from 9.6 to 10.5% (w.b.) after grinding, using the smaller screens for the Biofibre material, while the moisture content ranged from 7.9 to 8.6% (w.b.) for shives from Biolin. Also, smaller screen size reduced the geometric mean particle size for shives from both sources. The use of the smaller hammer mill screen resulted in an increase in both bulk and particle density of shives. There was a decrease in coefficient of the internal friction of shives from 0.20 to 0.14 and an increase in a cohesion of shives from 2.18 to 3.83 kPa when the screen size decreased from 6.4 to 3.2 mm. The flax shives contained cellulose (53.27%), hemicelluloses (13.62%), and lignin (20.53%) at a moisture content of 7.9% (w.b). Specific heat capacity of flax shives changed from 1.5 to 2.7 kJ/ (kg °C) when the moisture content was increased from 8 to14% (w.b.) and temperature from 15 to 80°C. The shives had the combustion energy of 17.67 MJ/kg at a moisture content of 8.1% (w.b.).<p> The smallest screen size (2.4 mm) resulted in the highest unit density (1010 kg/m3) and the highest durability (88%) in the pellets produced by the single-pelleting equipment. The change in length of pellets produced by the pilot-scale mill increased as canola meal increased from 18 to 24% at the highest moisture content (%). The pellets were more stable at the highest moisture content when the lowest canola meal used. The addition of 18% canola meal and grinds from a screen size of 6.4 mm produced the highest unit density in the pellets at all moisture levels. The highest bulk density (682 kg/m3) was obtained from shive mixtures with 18% canola meal and a moisture content of 8%. The highest hardness and durability were found for the shive pellets that were produced with 18% canola meal at a moisture content of 14% (w.b). Pellets that were produced at a moisture content of 14% (w.b) resulted in the lowest percentage of moisture absorption. The inclusion of the canola meal in the shive mixture resulted in an increase in the combustion energy of the pellets because of the fat content in the binder. The two levels of canola meal for shive pellets had essentially the same level of emissions. However, there were significant differences between shive pellets and commercial wood pellets in the level of the emissions. Lower amounts of methane (1.29 ppm) and oxygen (164.3 ppt) were found for flax shive pellets than of methane (1.63 ppm) and oxygen (176.6 ppt) in commercial wood pellets.<p> In short, pelleting of flax shives into fuel pellets improved the handling characteristics, increased bulk density and energy content. Fuel pellets made from flax shives had less emission of methane and oxygen from combustion when compared to commercial wood pellets.

The recent civil nuclear cooperation proposed by the Bush Administration and the Government of India has heightened the necessity of assessing India’s nuclear fuel cycle inclusive of nuclear materials and facilities. This agreement proposes to change the long-standing U.S. policy of preventing the spread of nuclear weapons by denying nuclear technology transfer to non-NPT signatory states. The nuclear tests in 1998 have convinced the world community that India would never relinquish its nuclear arsenal. This has driven the desire to engage India through civilian nuclear cooperation. The cornerstone of any civilian nuclear technological support necessitates the separation of military and civilian facilities. A complete nuclear fuel cycle assessment of India emphasizes the entwinment of the military and civilian facilities and would aid in moving forward with the separation plan. To estimate the existing uranium reserves in India, a complete historical assessment of ore production, conversion, and processing capabilities was performed using open source information and compared to independent reports. Nuclear energy and plutonium production (reactor- and weapons-grade) was simulated using declared capacity factors and modern simulation tools. The three-stage nuclear power program entities and all the components of civilian and military significance were assembled into a flowsheet to allow for a macroscopic vision of the Indian fuel cycle. A detailed view of the nuclear fuel cycle opens avenues for technological collaboration. The fuel cycle that grows from this study exploits domestic thorium reserves with advanced international technology and optimized for the existing system. To utilize any appreciable fraction of the world’s supply of thorium, nuclear breeding is necessary. The two known possibilities for production of more fissionable material in the reactor than is consumed as fuel are fast breeders or thermal breeders. This dissertation analyzes a thermal breeder core concept involving the CANDU core design. The end-oflife fuel characteristics evolved from the designed fuel composition is proliferation resistant and economical in integrating this technology into the Indian nuclear fuel cycle. Furthermore, it is shown that the separation of the military and civilian components of the Indian fuel cycle can be facilitated through the implementation of such a system.

Fuel cell performance was obtained as functions of the humidity at the anode and cathode sites, back pressure, flow rate, temperature, and channel depth. The fuel cell used in this work included a membrane and electrode assembly (MEA) which possessed an active area of 25, 50, and 100 cm2 with the Nafion® 117 and 115 membranes. Higher flow rates of inlet gases increase the performance of a fuel cell by increasing the removal of the water vapor, and decrease the mass transportation loss at high current density. Higher flow rates, however, result in low fuel utilization. An important factor, therefore, is to find the appropriate stoichiometric flow coefficient and starting point of stoichiometric flow rate in terms of fuel cell efficiency. Higher air supply leads to have better performance at the constant stoichiometric ratio at the anode, but not much increase after the stoichiometric ratio of 5. The effects of the environmental conditions and the channel depth for an airbreathing polymer electrolyte membrane fuel cell were investigated experimentally. Triple serpentine designs for the flow fields with two different flow depths was used. The shallow flow field deign improves dramatically the performance of the air-breathing fuel cell at low relative humidity, and slightly at high relative humidity. For proton exchange membrane fuel cells, proper water management is important to obtain maximum performance. Water management includes the humidity levels of the inlet gases as well as the understanding of the water process within the fuel cell. Two important processes associated with this understanding are (1) electro-osmotic drag of water molecules, and (2) back diffusion of the water molecules. There must be a neutral water balance over time to avoid the flooding, or drying the membranes. For these reasons, therefore, an investigation of the role of water transport in a PEM fuel cell is of particular importance. In this study, through a water balance experiment, the electro-osmotic drag coefficient was quantified and studied. For the cases where the anode was fully hydrated and the cathode suffered from the drying, when the current density was increased, the electro- osmotic drag coefficient decreased.

An investigation was performed to demonstrate system design for the delivery of water required for evaporative cooling of a proton exchange membrane fuel cell (PEMFC). The water delivery system uses spray nozzles capable of injecting water directly and uniformly to the nickel metal foam flow-field (element for distributing the reactant gases over the surface of the electrodes) on the anode side from which water can migrate to the cathode side of the cell via electroosmotic drag. For an effective overall cooling, water distribution over the surface of the nickel foam has to be uniform to avoid creation of hotspots within the cell. A prototype PEMFC structure was constructed modeled after a 35 kW electrical output PEMFC stack. Water was sprayed on the nickel metal foam flow-field using two types of nozzle spray, giving conical fog type flow and flat fan type flow. A detailed investigation of the distribution pattern of water over the surface of the nickel metal flow field was conducted. The motive behind the investigation was to determine if design parameters such as type of water flow from nozzles, vertical location of the water nozzles above the flowfield, area of the nozzles, or operating variables such as reactant gas flow had any effect on water distribution over the surface of the Ni-metal foam flow field. It was found that the design parameters (types of flow, area and location of the nozzle) had a direct impact on the distribution of water in the nickel metal foam. However, the operating variable, reactant gas flow, showed no effect on the water distribution pattern in the Ni-foam.

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The recent civil nuclear cooperation proposed by the Bush Administration and the Government of India has heightened the necessity of assessing India's nuclear fuel cycle inclusive of nuclear materials and facilities. This agreement proposes to change the long-standing U.S. policy of preventing the spread of nuclear weapons by denying nuclear technology transfer to non-NPT signatory states. The nuclear tests in 1998 have convinced the world community that India would never relinquish its nuclear arsenal. This has driven the desire to engage India through civilian nuclear cooperation. The cornerstone of any civilian nuclear technological support necessitates the separation of military and civilian facilities. A complete nuclear fuel cycle assessment of India emphasizes the entwinment of the military and civilian facilities and would aid in moving forward with the separation plan. To estimate the existing uranium reserves in India, a complete historical assessment of ore production, conversion, and processing capabilities was performed using open source information and compared to independent reports. Nuclear energy and plutonium production (reactor- and weapons-grade) was simulated using declared capacity factors and modern simulation tools. The three-stage nuclear power program entities and all the components of civilian and military significance were assembled into a flowsheet to allow for a macroscopic vision of the Indian fuel cycle. A detailed view of the nuclear fuel cycle opens avenues for technological collaboration. The fuel cycle that grows from this study exploits domestic thorium reserves with advanced international technology and optimized for the existing system. To utilize any appreciable fraction of the world's supply of thorium, nuclear breeding is necessary. The two known possibilities for production of more fissionable material in the reactor than is consumed as fuel are fast breeders or thermal breeders. This dissertation analyzes a thermal breeder core concept involving the CANDU core design. The end-oflife fuel characteristics evolved from the designed fuel composition is proliferation resistant and economical in integrating this technology into the Indian nuclear fuel cycle. Furthermore, it is shown that the separation of the military and civilian components of the Indian fuel cycle can be facilitated through the implementation of such a system.