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 43 for “"full-core"”.
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Advanced response matrix methods for full core analysis
Modeling full reactor cores with high fidelity transport methods is a difficult task, requiring the largest computers available today. This thesis presents work on an alternative approach using the eigenvalue response matrix method (ERMM). The basic idea of ERMM is to decompose a reactor spatially …
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LWR fuel reactivity depletion verification using 2D full core MOC and flux map data
… decrement biases and uncertainties using in-core flux map data from operating power reactors has previously been conducted employing analytical methods to systematically determine experimental fuel reactivities that best match measured fission rate distributions. This optimal core reactivity …
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Full core 3D neutron transport simulation using the method of characteristics with linear sources
… neutron transport-based simulation tools for full core Light Water Reactor (LWR) analysis has been a long-standing goal of the reactor physics community. While direct transport simulations have previously been far too computationally expensive, advances in computer hardware have allowed large …
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Neutronic feasibility assessment of full-core applications of evolutionary mixed-oxide fuels in pressurized water reactors
Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Nuclear Engineering, 1998.
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Parallel, asynchronous ray-tracing for scalable, 3D, full-core method of characteristics neutron transport on unstructured mesh
One important goal in nuclear reactor core simulations is the computation of detailed 3D power distributions that will enable higher confidence in licensing of next-generation reactors and lifetime extensions/power up-rates for current-generation reactors. To date, there have been only a few …
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Application of data-driven methods in nuclear fuel performance analysis
… significantly reduced uncertainty. Second, while full-core monitoring of fuel behaviors can provide the most realistic assessment of safety margins, its computational cost for use in design and operation optimization is prohibitive. Machine learning (ML) methods were used to construct fast-running …
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The x-ray edge in alkali metals and alloys, an ab-initio study
… of environments and results are compared to full core Hartree Fock results and experiment. It is found that this methodology reproduces experimental results as accurately as the full core Hartree Fock theory. Correlation corrections are included using many body Raleigh Schrodinger …
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Cumulative migration method for computing multi-group transport cross sections and diffusion coefficients with Monte Carlo calculations
… deterministic methods are needed for the many full-core calculations required for safe and efficient operation of nuclear power plants. Multi-group diffusion coefficients and transport cross sections are the crucial parameters that balance efficiency and accuracy in full-core simulations. …
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The X-Ray Edge in Alkali Metals and Alloys: An Ab-Initio Study
… of environments and results are compared to full core Hartree Fock results and experiment. It is found that this methodology reproduces experimental results as accurately as the full core Hartree Fock theory. Correlation corrections are included using many body Raleigh Schrodinger …
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Parallel algorithms for Monte Carlo particle transport simulation on exascale computing architectures
… that would prevent their immediate adoption for full-core analyses. In this thesis, algorithms are proposed both to ameliorate the degradation in parallal efficiency typically observed for large numbers of processors and to offer a means of decomposing large tally data that will be needed for …
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Development of the random ray method of neutral particle transport for high-fidelity nuclear reactor simulation
… engineering is the high-fidelity simulation of a full nuclear reactor core by way of a general simulation method. General full core simulations can potentially reduce design and construction costs, increase reactor performance and safety, reduce the amount of nuclear waste generated, and allow for …
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Improved 3D modelling of CANDU reactors using transport-fitted diffusion coefficients
To model the neutronic physics behavior of the core in CANDU 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 …
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A novel equivalence method for high fidelity hybrid stochastic-deterministic neutron transport simulations
… sections to compute accurate solutions at the full core scale. This hybrid computation scheme makes the most of both worlds to achieve fast and accurate reactor physics simulations. Among the few remaining approximations are neglecting the angular dependence of group cross sections, which lead …
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Investigation of sub-cell homogenization for PHWR lattice cells using superhomogenization factors
To avoid the computational effort associated with full-core neutron transport calculations, full-core neutronics calculations for Pressurized Heavy-Water Reactors (PHWRs) are usually performed in diffusion theory using an approximate core model, whereby only two energy groups are utilized and …
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Advanced online fuel reprocessing simulation for thorium-fueled molten salt breeder reactor
… composition (when multiplication factor of the full-core model and the U-233 concentration in the fuel salt are invariant in time); (2) determining the effect of the fuel salt irradiation with online reprocessing on MSBR operations; and (3) estimating MSBR fuel cycle performance by computing the …
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Multi-physics and technical analysis of high-temperature gas-cooled reactors for hydrogen production
… accuracy. The following analysis focuses on the full-core problem and compares different aspects of the simulations, concluding that Moltres obtains reasonably accurate results. The final study on stand-alone neutronics describes Moltres results of Phase I Exercise 1 of the OECD/NEA MHTGR-350 …
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Three dimensional heterogeneous finite element method for static multi-group neutron diffusion
Because current full-core neutronic-calculations use two-group neutron diffusion and rely on homogenizing fuel assemblies, reconstructing pin powers from such a calculation is an elaborate and not very accurate process; one which becomes more difficult with increased core heterogeneity. A …
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Memory efficient indexing algorithm for physical properties in OpenMC
… simulations. The target problem for OpenMC is a full core high-fidelity multi-physics coupled simulation. This encompasses not only nuclear physics, but also material science and thermohydraulics. One of the challenges associated with this problem is efficient data management, as the memory …
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Reactor agnostic multi-group cross section generation for fine-mesh deterministic neutron transport simulations
A key challenge for full-core transport methods is reactor agnostic multi-group cross section (MGXS) generation. Monte Carlo (MC) presents the most accurate method for MGXS generation since it does not require any approximations to the neutron flux. This thesis develops novel methods that use MC to …
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Impact assessment for the MIT Research Reactor low enrichment uranium fuel fabrication tolerances
… specification parameters on all levels of the core, ranging from full-core alterations to individual spots on the fuel plates were analyzed. Evaluations at the design tolerances, and beyond, were conducted through neutronics and thermal hydraulics calculations.
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