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 44 for “"once-through"”.
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A performance model for a helically coiled once-through steam generator tube
Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Nuclear Engineering, 1979.
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CFD Analysis of Aspirator Region in a B&W Enhanced Once-Through Steam Generator
… ratio in the aspirator region of an enhanced once-through steam generator of the Babcock & Wilcox design. This information is important to the development of accurate RELAP5 models, steam generator level calculations, steam generator downcomer models, and flow induced vibration analyses. The …
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Computational Fluid Flow Analysis of the Enhanced-Once through Steam generator Auxiliary feedwater system
The once through steam generator (OTSG) is a single pass counter flow heat exchanger in which primary pressurized water from the core is circulated. Main Feedwater is injected in an annular gap on the outer periphery of the steam generator shroud such that it aspirates steam to preheat the …
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Integrated network-based thermofluid model of a once-through boiler at full- and part-load
… thermofluid network model of a tower type once-through boiler was developed using the Flownex simulation environment. The furnace model assumes complete, infinitely fast combustion with a specified value of unburned carbon and excess air. The radiation heat transfer in the furnace is …
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Kalman Filtering and its Application to On-Line State Estimation of a Once-Through Boiler
… Kalman filtering of multiplex systems through the development of two main ideas, namely, integration of the unscented transforms with linearly implicit methods and incorporation of simulation errors in the state estimation problem. The newly developed techniques are then applied to the …
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A methodology to investigate the cause of quenching in once-through tower type power plant boilers
… prone to thermal fatigue cracking as a result of through-wall temperature gradients during start up and shutdown. These temperature gradients can be significantly amplified during quenching when components at high temperature are unintentionally exposed to colder liquid or steam. Such quench …
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Modeling Two-Phase Flow in the Downcomer of a Once-Through Steam Generator using RELAP5/MOD2
… an accurate model of the downcomer of the once-through steam generator (OTSG) developed by Babcock & Wilcox, using RELAP5/MOD2. While the physical model can be easily developed, several parameters are left to be adjusted to optimally model the downcomer and match data that was retrieved in …
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Integrated process and control modelling of water recirculation in once-through boilers during low load and transient operation
… and shutdown, the required water flow rate through the evaporator tubes of once-though boilers must be significantly higher than the evaporation rate to protect against overheating of the tubes until once-through operation is reached. Controlling the minimum required water flow rate through …
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Waste to fuel: designing a cobalt based catalyst and process for once-through Fischer-Tropsch synthesis operated at high conversion
… Furthermore, a detailed design of the proposed once-through Fischer-Tropsch biogas-to-fuel plant will be evaluated using data from the catalytic experiments. An investigation into the effect of high conversion on the activity and selectivity of 0.05Pt-22Co/Al2O3 was conducted in a slurry bed …
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Nuclear fuel cycles for mid-century development
… was carried out. Fuel cycles reviewed include: once-through fuel cycles in LWRs, PHWRs, HTGRs, and fast gas cooled breed and burn reactors; single-pass recycle schemes: plutonium recycle in LWRs and direct-use of spent PWR fuel in CANDU reactors (DUPIC); multi-pass recycle schemes: transmutation …
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Evaluation of alternative fuel cycle strategies for nuclear power generation in the 21st century
The deployment of fuel recycling through either CONFU (COmbined Non-Fertile and UO2 fuel) thermal watercooled reactors (LWRs) or fast ABR (Actinide Burner Reactor) reactors is compared to the Once-Through LWR reactor system in terms of accumulation of actinides over the next 100 years under the …
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A Comparative Study of Cooling System Parameters in U.S. Thermoelectric Power Plants
… that it would be most cost effective for once-through cooling systems to be replaced with recirculating- pond instead of recirculating- tower systems. The implications of this study are that as power plant owner's struggle in balancing cost with water dependence, several parameters must …
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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
… 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 economic. The present work investigates the …
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Levelized Cost of Fuel (LCOF) studies for microreactors using TRISO fuel in hydride and beryllium-based composite moderators in open and closed fuel cycles
… pebble-bed cores—using four composite moderator concepts (MgO–Be, MgO–BeO, MgO–YH, MgO–ZrH). These options are compared against a prismatic graphite benchmark, under both once-through and continuous-recycle fuel cycles. In once-through prismatic systems, hydride-based moderators can reduce overall …
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Rethinking the light water reactor fuel cycle
The once through nuclear fuel cycle adopted by the majority of countries with operating commercial power reactors imposes a number of concerns. The radioactive waste created in the once through nuclear fuel cycle has to be isolated from the environment for thousands of years. In addition, plutonium …
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Global terrestrial uranium supply and its policy implications : a probabilistic projection of future uranium costs
… over the next half-century are enabled through the development of a comprehensive model for resource cost ($/kg of U30 8) versus cumulative energy generation (GWe-yr). The probabilistic cost model incorporates three sub-models including Deffeyes' crustal abundance model, …
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Analyzing the proliferation resistance of advanced nuclear fuel cycles : in search of an assessment methodology for use in fuel cycle simulations
… to evaluate the proliferation resistance of once-through, COmbined Non-Fertile and Uranium (CONFU), Mixed-Oxide (MOX), and Advanced Burner Reactor (ABR) fuel cycles. The metrics are roughly categorized in three groups: material characteristics, material handling characteristics, and …
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Fuel Cycle Modeling Improvements and Multi-Tiered Recycling With A Sodium-Cooled Heterogeneous Innovative Burner Reactor
… strategy offers improvements over the previous once-through SCHIBR model by further reducing the radiotoxicity of the discharged waste and making plutonium available for use in additional SCHIBR reactors.</p>
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Design and fabrication of an internal condensation loop for effectiveness and robustness testing of nanostructured superhydrophobic steam condenser
… process. Industrial condensers feature once-through water cooling, and the substantial amount of water they consume coupled with the increasing scarcity of freshwater supplies provides further motivation to focus on the condensation process. Condensation in these systems occurs …
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Used Nuclear Fuel Actinide Management in a Sodium- Cooled Heterogeneous Innovative Burner Reactor
… of the discharged waste to less than 25% of the once-through cycle after 100 years. The design can be achieved within the currently developed technology for reactor and fuel production. Additionally, the reactor design meets all current standards for safe operation and would provide additional …
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