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 12 of 12 for “"Reactivity coefficients"”.
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The "virtual density" theory of neutronics
… involving weighting the uniform radial swelling reactivity coefficient by the power distribution. These approximations agree fairly well with experimental data for flowering in some cores, but they are not fully generic and cannot be trusted for arbitrary distortions. Boundary perturbation …
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Neutronic characterization of a Molybdenum-99-producing CANDU fuel bundle and implications for reactivity-device worth and refuelling strategies
… to those of the SCB. This includes derivation of reactivity coefficients, incremental macroscopic cross sections for reactivity devices and refuelling strategies for the MPB. The evaluations are made using well-established analysis methods and models where applicable, and new or improved methods …
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Developing a fresh core neutronic model at 300K for a VVER-1000 reactor type using MCNP6
… parameters including the 𝑘𝑒𝑓𝑓 , power profiles, reactivity coefficients and control rod worth were evaluated for the reactor core. The present study looks at the ability of the VVER-1000 reactor system to provide appropriate neutronics behaviour of the fresh core at the start of the initial cycle …
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Computational treatments for neutron resonance elastic scattering in Monte Carlo nuclear simulations
… and macroscopic values such as temperature reactivity coefficients. First, this research validates a faster computational treatment for resonance scattering--the accelerated resonance elastic scattering (ARES) kernel sampling method--against the already verified Doppler broadening rejection …
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Calculating reaction rate derivatives in Monte Carlo neutron transport/
… provides derivatives of tallied quantities like reactivity and fission reaction rates with respect to material density, temperature, etc. These derivatives directly provide reactivity coefficients and they can also be used to extrapolate and predict small changes in reactor parameters. Notably, a …
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Nuclear reactor multi-physics simulations with coupled MCNP5 and STAR-CCM+
… rate distributions are realistic and intuitive. Reactivity coefficients are also deemed reasonable in comparison to historically reported data. Mesh count is held to a minimum in both models to expedite computation time on a 2.8 GHz quad core machine with 1 GB RAM. The simulations on a quad core …
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An evolutionary fuel assembly design for high power density BWRs
… burnup. Also, the void and fuel temperature reactivity coefficients are both negative and close to those of the traditional BWR core. - The susceptibility of the large assembly core to thermalhydraulic/neutronic oscillations of the density-wave type was explored with an in-house code.
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A Monte Carlo framework for nuclear data uncertainty propagation via the windowed multipole formalism
… calculated quantities, such as K[subscript eff], reactivity coefficients, multigroup cross sections, and reaction rate ratios, that arise due to uncertainties in the underlying nuclear data. This framework relies on first order uncertainty analysis using sensitivity methods. The major innovation …
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Ageing Mechanisms in Automotive Catalysts
… relating to a RAT-A cycle. The thermal reactivity coefficients, R-factors, for static ageing in different ageing atmospheres were calculated and compared to those recommended by the EPA for dynamic ageing. Finally, using the results achieved from these laboratory ageing methods, …
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Reactor physics considerations for implementing silicon carbide cladding into a PWR environment
… account as well as acceptable values for the reactivity feedback and control mechanisms and shutdown margin. The Studsvik Core Management System, which consisted of CASMO-4E, CMS-Link, and SIMULATE-3, provided an accurate tool to design the new core loading patterns that would satisfy current …
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Design Space Exploration for Salt Cooled Reactor Systems
… neutronic designs at BOL. Constrained by reactivity coefficients and burnup while targeting high burnup-to-enrichment ratios (BU/e), four optimised neutronic design streams were recommended: 1) solid UC fuelled FLiBe cooled FHR, 2) solid FCM fuelled FLiBe cooled FHR, 3) annular FCM fuelled …
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Probabilistic transient analysis of fuel choices for sodium fast reactors
… Important transient characteristics, such as the reactivity coefficients, were treated as random variables which determine the success or failure of surviving the transient. In this context, success is defined as the cladding remaining intact and the avoidance of sodium boiling. In order to avoid …