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 20 of 21 for “"Natural uranium"”.
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A study of the fast fission effect for single natural uranium rod
Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Nuclear Engineering, 1963.
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Fast neutron leakage spectra for assemblies containing thorium, D{u2082}O and natural uranium
… data of the ENOF/B-II files for thorium, natural uranium and heavy water. The experimental measurements of fast neutron spectra have been in two lattices of thorium metal and D₂O, a cylindrical array of close-packed natural uranium metal slugs in air, a D₂O sphere and cylinder, and a …
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Feasibility Study of a Natural Uranium Neutron Spallation Target using FLiBe as a Coolant
… Fluoride (LiF-BeF2) or FLiBe as a coolant with a natural uranium neutron spallation source applied to an accelerator driven sub-critical molten salt reactor. The study utilized two different software tools, MCNPX 2.6 and FLUENT 12.1. MCNPX was used to determine the neutronics and heat deposited in …
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A fission-fusion hybrid reactor in steady-state L-mode tokamak configuration with natural uranium
… L-mode tokamak configuration with a subcritical natural or depleted uranium pebble bed blanket. A liquid lithiumlead alloy breeds enough tritium to replenish that consumed by the D-T fusion reaction. Subcritical operation could obviate the most challenging fuel cycle aspects of fission. The …
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Nuclear Fuel Requirements For the American Economy - A Model
… reactors, the number of reactors, and masses of natural Uranium and other fuels used.</p> <p>Energy demand, including electricity and hydrogen, is obtained from US DOE historical data and projections, along with other studies of potential hydrogen demand. An option to include other energy demand …
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Consumption minimization of the uranium resources by the use of mixed-oxide fueled reactors
The need to conserve the limited natural uranium resources necessitates the determination of the optimal use of M0X fueled reactors under various reactor growth scenarios. The reactor growth scenarios include an industry that attains 400, 507, and 600 operating reactors by the year 2000. The …
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The design and construction of a subcritical nuclear reactor
… program at Virginia Polytechnic Institute. Natural uranium fuel and reactor grade graphite were used as building materials. Considering that no two samples of moderator have the same characteristics, the resulting parameters measured on this reactor are in good agreement with published data. …
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Minimization of blending losses to determine optimal standard enrichments of nuclear fuel
… reactor fuel standardization of potintial uranium enrichment alternatives such as the gas centrifuge. Using a mixed-integer linear program, the model minimizes present worth costs for a 39-product-enrichment reference case. For four ingredients, the marginal blending cost is only 0.18 …
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The design, construction, and study of the effect of a cadmium-aluminum shield for the V. P. I. subcritical reactor
… region counting rates are compared. The natural-uranium slugs and the highly radioactive source are padlocked within the shield. The assembly is also protected from contamination. Practically no additional biological protection is afforded by the shield due to the neutron-gamma reaction …
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Improved 3D modelling of CANDU reactors using transport-fitted diffusion coefficients
… pressure tube type heavy water reactors with natural-uranium fuel, two levels of calculations are required. Initially, lattice-level transport calculations are carried out to obtain, with high detail and accuracy, the flux distribution inside the lattice cell and composition of the nuclear …
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Impact of alternative nuclear fuel cycle options on infrastructure and fuel requirements, actinide and waste inventories, and economics
… practiced in the U.S. leads to accumulation of uranium, transuranic (TRU) and fission product inventories in the spent nuclear fuel. Various separation and recycling options can be envisioned in order to reduce these inventories while extracting additional energy and sending the ultimate waste …
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Neutron radiography with the VPI & SU research reactor
… and white pine test pieces; 3) thorium and natural uranium slugs; 4) enriched uranium fuel plate; 5) used and unused boral control elements; 6) miscellaneous small test objects. The results were, in general, good. Exposure times and limitations were found to be in agreement with other …
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Optimization of DUPIC cycle environmental and economic performance
… to that of PWR and CANDU fuel cycles in terms of uranium utilization and spent fuel production efficiency. The DUPIC cycle was found to be most efficient in terms of minimizing spent fuel production as well as most efficient (within limits) in terms of maximizing natural uranium utilization. It …
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The interaction of fast neutrons with shielding and fusion blanket materials
… emission spectra from a graphite cube, and from natural uranium, lithium fluoride, graphite, lead and steel slabs bombarded with 14.1 MeV neutrons were measured to test nuclear data and calculational methods for D - T fusion reactor neutronics. The neutron spectra measured were performed by an …
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Global terrestrial uranium supply and its policy implications : a probabilistic projection of future uranium costs
An accurate outlook on long-term uranium resources is critical in forecasting uranium costresource relationships, and for energy policy planning as regards the development and deployment of nuclear fuel cycle alternatives. In this study, which was part of the MIT Study on the Future of the Nuclear …
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Uranium in groundwater and its potential as a natural contaminant in the Cherokee Basin, southeastern Kansas
… The ingestion of radioactive nuclides such as uranium has been associated with renal and cancer-related issues in humans. Many previous studies have focused on anthropogenic uranium contamination. Here, we examined the potential for natural uranium contamination from water-rock interaction in …
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Variations in the particulate flux of ²³⁰Th and ²³¹Pa and paleoceanograhpic applications of the ²³¹Pa/²³¹Th ratio
… radionuclides produced from the decay of natural uranium, is found widely within the oceans. This large scale fractionation was investigated in samples of sinking particulate matter collected with sediment traps and in deep-sea sediment cores. New analytical methods for uranium, thorium, …
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Conceptual design of a breed & burn molten salt reactor
… breed-and-burn (B$\&$B) designs to achieve high uranium utilisation with a simple, passively safe design. A central challenge in design of the BBMSR fuel is balancing the neutronic requirement of large fuel volume fraction for B$\&$B mode with the thermal-hydraulic requirements for safe and …
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A strategy for transition from a uranium fueled, open cycle SFR to a transuranic fueled, closed cycle sodium cooled fast reactor
… technology. A strategy centered around using uranium-fueled fast reactor cores in a once-through mode-a uranium startup fast reactor (USFR)-decouples fast reactor commercialization from fuel reprocessing and enables transition to a recycle mode once the technology becomes available and …
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The preparation and characterisation of highly selective adsorbents for fission product removal from acid solutions
… One aim of reprocessing is to recover unused uranium (U-238 and U-235) and plutonium isotopes thereby preventing them from being wasted. This can save up to 30% of the natural uranium that is required each year for the fabrication of new nuclear fuel. A second aim is to reduce the volume of …
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