Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 18 of 18 for “"Uranium oxide"”.
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Investigation of uranium oxide of low oxidation state
Thesis (B.S.)--Massachusetts Institute of Technology, Dept. of Chemistry, 1957.
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Nuclear forensic applications of uranium oxide chemistry and morphology
… signatures are introduced by the aging in bulk uranium oxide samples, and whether those signatures can be used to elucidate the conditions under which the materials were stored. This thesis is concerned with the analysis of uranium oxide samples: both high-purity UO2, alpha-U3O8, and alpha-UO3 …
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Growth, phase transformation, and self-assembly in iron oxide and uranium oxide nanostructures
… of the products of hierarchical self-assembly of uranium polyoxometalate clusters.
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Waste characteristics of spent nuclear fuel from a pebble bed reactor
… The interactions of silicon carbide with uranium oxide fuel and its implications to long term storage at the repository are examined. There are three primary conclusions to this thesis. First, the area required to store pebble fuel is less than the area required to store light water …
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Validation of the use of low enriched uranium as a replacement for highly enriched uranium in US submarine reactors
The US Navy has long used highly enriched uranium (HEU) in naval reactors for a variety of technical reasons. In a series of studies, the Department of Naval Reactors determined that switching to low enriched uranium (LEU) was impossible using current fuel designs, but may be possible with a …
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Electrochemical study of corrosion phenomena in zirconium alloys
… The limitations placed on the bum-up of uranium oxide fuel correlates to the amount of corrosion seen through a directly measurable oxide thickness on the waterside of the zirconium alloy cladding. This oxide corrosion product directly correlates to distance from structural components, …
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An analysis of plutonium accountability in the COPRECAL process
… solution must be altered to generate plutonium-uranium oxide powder. The COPRECAL process is designed to produce this solid. The COPRECAL process allows uranium and plutonium to be extracted from spent-fuel for reuse in commercial lightwater reactors. The COPRECAL process is unique in that no …
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Thermal hydraulic analysis of hydride fuels in BWR's
… nuclear reactors. All results hold equally for uranium dioxide as well as hydride fuel since the design limits imposed, critical heat flux, maximum flow velocity and pressure drop constrain only pin array geometry and diameter. It is shown that applicable uranium oxide and hydride fuel limits …
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Separation of fission products from irradiated uranium by peroxide precipitation
<p>Aqueous precipitation of uranium as the peroxide has been used as a purification procedure since the early days of the Manhattan Project. The procedure has successfully produced an extremely pure product when handled in small batches. Heretofore peroxide precipitation has been utilized for …
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Economics of nuclear fuel cycles : option valuation and neutronics simulation of mixed oxide fuels
… to keep scenarios economically comparable. For Uranium Oxide (UOX) and Mixed Oxide (MOX) fuels, a traditional way to achieve this is to evaluate both fuels on the deterministic premise that the fuel will be sent to geologic disposal once spent. This methodology often leads to higher costs for …
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The fabrication of nano-scale engineered surfaces to investigate the enhancement of boiling heat transfer and CHF in nuclear reactors
… in the nuclear industry. Through growing zinc oxide nanowires (ZnO NW) on the surface of zircaloy, which clads the uranium oxide fuel, the project aims to increase the heat flux limit, i.e., the critical heat flux (CHF), resulting in a boiling crisis. That allows for improvement on the safety …
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Fluence-limited burnup as a function of fast reactor core parameters
… fluence in the cladding, especially for reduced uranium enrichment cores using high-albedo MgO reflectors. The intent of this thesis was to determine the best design parameters - fuel type, fuel compound, fuel arrangement, and coolant - while observing these limitations. The ERANOS code was used …
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Innovative design of uranium startup fast reactors
… Fast reactors play an important role in saving uranium resources and reducing nuclear wastes. Conventional fast reactors rely on transuranic fuels from reprocessing facilities, which are not available in the U.S. Thus, deployment of fast reactors requires decoupling from reprocessing facilities. …
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Determination of UO2 thin films mechanical properties under heavy ion irradiation using nanoindentation and finite element modeling
The mechanical response of UO2 to irradiation is becoming increasingly important due to the shift to higher burn-up rates in the next generation of reactors. In the current study, thin films of UO2 were deposited on YSZ substrates using reactive-gas magnetron sputtering. Nanoindentation was used to …
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Studies of Used Fuel Fluorination and U Extraction Based on Molten Salt Technology for Advanced Molten Salt Fuel Fabrication
… (UNF) and the third is a method of separating uranium (U) from lithium fluoride (LiF) and thorium fluoride (ThF4) salt also known as FLiTh for a thorium (Th) fuel cycle. The first technique proposed for UNF recycling was to use the cladding as an anode to oxidize the zircaloy and dissolve it …
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X-ray photoelectron spectroscopy (XPS) study of single crystal UO2 and U3O8 on r-plane sapphire and yttrium stabilized zirconium (YSZ) substrates
… system to grow single crystal thin films of Uranium Oxides with and without specifically added Neodymium impurities. To do this we analyzed our thin films using X-ray Photoelectron Spectroscopy (XPS), X-ray Diffraction (XRD), Rutherford Backscattering Spectroscopy (RBS), and Secondary Ion …
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Microstructural investigations of ion (Kr) irradiated UO2
A single crystal thin film of UO2 on a YSZ substrate was irradiated with 1MeV Kr ions at doses ranging from 1x1014 ions/cm2 to 1x1016 ions/cm2 and temperatures ranging from room temperature to 1000°C. These irradiations were conducted ex situ with one in situ irradiation at 800°C. Post irradiation …
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Reduction of Solid Uranium Dioxide in Calcium Salts
… cooperation, 2014) has pointed out is to utilize uranium resources to the maximum and recycle spent nuclear fuel through burn-up in the Generation IV reactor designs, one of which is the molten salt reactor (MSR). Therefore, the MSR can use the spent nuclear fuel as a fresh fuel when the actinides …