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 17 of 17 for “"control rods"”.
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A study of the reactivity effects of the V. P. I. nuclear reactor
… temperature changes 3) Xenon poisoning The control rods have to be continuously positioned so that the total reactivity change of these parameters is nullified. The reactivity effects of the fuel and coolant have been combined into one temperature coefficient because for this investigation …
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Design Options to Address Submersion Criticality for Low-Enriched Uranium Nuclear Thermal Propulsion Rocket
… considered such as enhanced accident tolerant control drums, coolant channel radius adjustment, telescoping control rods, and the implementation of a spectral shift via enrichment zoning. Analysis was performed using Monte-Carlo code SERPENT 2.1.3.1, supported by 1D thermal hydraulics modeling …
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Combining thorium with burnable poison for reactivity control of a very long cycle BWR
… at BOL which would have to be suppressed by control rods. The most important advantage of B4C over others is the saving of uranium inventory needed to achieve the target exposure of 15 effective full power years (EFPY). Further analysis for transient conditions must be performed to ensure …
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Optimization of actinide transmutation in innovative lead-cooled fast reactors
… assemblies with streaming elements, double-entry control rods and special absorbing materials that establish favorable neutronics characteristics and excellent self-controllability features, comparable to those of the Integral Fast Reactor (IFR) core.
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Reactor configurations to support advanced material research
… 19.75% <sup>235</sup>U enrichment. The fuel and control rods system geometries were adopted from Missouri S&T Reactor (MSTR).</p> <p>A high-power configuration (HPC) at 2 megawatts and low-power configuration (LPC) at 200 kilowatts were considered. Neutronic performances of the configurations …
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Measurement and analysis of the resolved resonance cross sections of the natural hafnium isotopes
… cross section. It can be used in reactor control rods to regulate the fission process. The NEA High Priority Request List for nuclear data presents a need for improved characterisation of the hafnium cross section in the resolved resonance region. This thesis presents new resonance cross …
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An evolutionary fuel assembly design for high power density BWRs
… within a large assembly. Twenty-five water rods with 27 mm diameter maintain the moderating power and accommodate as many finger-type control rods. The total number and positions of the control rod drive mechanisms are not changed, so existing BWRs can be retrofitted with the new fuel …
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Modeling and design of reload LWR cores for an ultra-long operating cycle
… poisons to hold down excess reactivity and to control power peaking. The BWR employs only Gd203. Both core designs require higher worth control rods in order to meet shutdown safety requirements. Fuel performance issues were also investigated. The presence of high burnup fuel assemblies in …
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Space-Time Kinetics of the AGN-201M Research Reactor at the University of New Mexico
… are defined by moving the coarse and fine control rods to unique positions in the core. These experiments also provided data for control rod integral and differential reactivity worth estimates. Thermal flux measurments taken radially in the glory hole region of the AGN reactor were also …
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Conceptual design of an annular-fueled superheat boiling water reactor
… are used to adjust the core flow rate. Cruciform control rods are used to control the reactivity of the core, but more of them may be needed than a traditional BWR in view of the harder spectrum. The major design constraints have been identified and evaluated in this work. The ASBWR is found …
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Development and benchmarking of advanced FM-based particle transport algorithms for steady-state and transient conditions, implementation in RAPID and its VRS web-application
… methodology for accounting for the movement of control rods in the JSI TRIGA reactor has been developed. This methodology, referred to as FM-CRd, is capable of determining the neutron flux distribution changes due to the presence of control rod in real-time. The FM-CRd method has been validated …
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Transient flow boiling CHF under exponentially escalating heat inputs
… e.g. by an unanticipated extraction of the control rods, the reactor power may increase exponentially. The period of the exponential rise, τ, depends on the amount of positive reactivity inserted, as well as the fuel composition. During such an event, boiling of the water coolant can provide …
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The use of reduced-moderation light water reactors for transuranic isotope burning in thorium fuel
… of ~40 GWd/t is possible in RMPWRs. Reactivity control is a challenge due to the reduced worth of neutron absorbers in the hard neutron spectrum, and their detrimental effect on the VC, especially when diluted, as for soluble boron. Control rods are instead used to control the core. It appears …
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Reactor protection system design alternatives for sodium fast reactors
… self-actuated shutdown systems, articulated control rods, and seismic anticipatory scram systems. This study investigates the performance of these systems in sodium fast reactors. To analyze the impact of these proposed design alternatives, a model to analyze plant performance that …
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Analysis and optimization of a new accident tolerant fuel called fuel-in-fibers
… analysis showed that using B4C instead AgInCd control rods is needed. A design optimization was also performed to calculate the ideal geometry for Fuel-in-Fibers concept. An in-house MATLAB single channel code, built to evaluate PWR Thermal Hydraulic and Structural performance, was used to vary …
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The Design of Reactor Cores for Civil Nuclear Marine Propulsion
… and designs of the fuel composition, reactivity control, assembly geometry, and core loading in order to meet the operational needs of a marine propulsion reactor. In this reactor physics and 3D coupled neutronics/thermal-hydraulics study, we attempt to design a civil marine reactor core that …
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Development of optimized core design and analysis methods for high power density BWRs
… of the ABWR values. Traditional cruciform form control rods are used, which restricts the assembly span to less than 1.2 times the current GE 14 design due to limitation on shutdown margin. Thus, it is possible to increase the power density and specific power by 65%, while maintaining the …