자료유형  

 학위논문

Control Number  

0016935939

International Standard Book Number  

9798380714716

Dewey Decimal Classification Number  

621

Main Entry-Personal Name  

Takasugi, Cole Nathaniel.

Publication, Distribution, etc. (Imprint  

[S.l.] : North Carolina State University., 2023

Publication, Distribution, etc. (Imprint  

Ann Arbor : ProQuest Dissertations & Theses, 2023

Physical Description  

1 online resource(143 p.)

General Note  

Source: Dissertations Abstracts International, Volume: 85-05, Section: B.

General Note  

Advisor: Smith, Ralph;Gimenez, Agustin Abarca;Martin, Nicolas;Avramova, Maria;Ivanov, Kostadin.

Dissertation Note  

Thesis (Ph.D.)--North Carolina State University, 2023.

Restrictions on Access Note  

This item must not be sold to any third party vendors.

Summary, Etc.  

요약The development of Generation IV advanced reactor systems represents a significant effort to improve the competitiveness of nuclear power in the energy market by improving safety, economics, proliferation resistance, and sustainability. Sodium-cooled fast reactors (SFRs) are one of the more technically mature advanced reactor concepts, having been demonstrated in historical and modern fast reactor programs. This dissertation presents extensions to and applications of the NEM (Nodal Expansion Method) nodal diffusion code and CTF subchannel thermal-hydraulics code for modeling and simulation of SFR cores. The NEM code is developed by the Reactor Dynamics and Fuel Modeling Group (RDFMG) at North Carolina State University (NCSU), while CTF is codeveloped by NCSU and Oak Ridge National Laboratory. Both NEM and CTF have traditionally been developed for the modelling of conventional light water-cooled reactor (LWR) systems; however, updates were made to both codes to improve modeling capabilities for sodiumcooled fast reactor cores, including as a coupled CTF/NEM multi-physics platform.The development of computationally efficient tools for modelling and simulation of reactor core behavior is important to reactor design and safety assessment. The large computational expense involved in utilizing high-fidelity neutronics and thermal-hydraulics codes may limit the practicality of detailed full-core multi-physics simulations, while the application of lower-fidelity counterparts may involve simplifications which limit the capability of these codes to capture local behavior accurately. High-to-low (Hi2Lo) fidelity model informing procedures offer a balanced approach, informing the computationally efficient lower-fidelity codes with information or data from high-fidelity simulations to improve their accuracy. Developments to NEM and CTF codes have included the application of Hi2Lo procedures.The NEM nodal diffusion code is capable of modeling Cartesian, hexagonal-z and cylindrical nodal geometries for both steady-state and transient conditions utilizing the nodal expansion method. Equivalence techniques, such as discontinuity factors (DFs), may be applied to improve the accuracy of diffusion methods in a two-step scheme supported by high-fidelity calculations. Discontinuity factors attempt to preserve fluxes or partial currents at interfaces of spatially homogenized regions and are traditionally generated from two-dimensional (2D) lattice calculations. However, more advanced applications may utilize side-dependent and/or axial discontinuity factors based on three-dimensional (3D) reference calculations and corresponding 3D equivalence procedures. The NEM code was developed to make efficient use of group constants generated from the Serpent Monte Carlo code in a two-step Hi2Lo computational scheme including options up to 3D side-dependent discontinuity factors. Development of this capability for the hexagonal-z nodal geometry has demonstrated significant improvements to NEM's SFR modelling capabilities, while the two-step scheme and supplementary developments have extended the flexibility of NEM to manage thermal expansion effects which are prevalent in SFR designs.The CTF subchannel thermal-hydraulics code, traditionally utilized for steady-state and transient LWR reactor modeling, has been modified to include liquid sodium material properties and correlations for SFR wire-wrapped rod bundle and ducted geometries. Continued developments for SFR applications have been made, including the implementation of additional correlations for wire-wrapped rod bundles and sets of correlations for the inter-assembly flow region. Additional features have been added to CTF to determine local linear expansion factors (LEFs) for fuel, cladding, and structural material expansions with on-line adjustment of subchannel geometry and heat transfer equations for sodium-bonded metallic fuels. Hi2Lo information is primarily implemented in CTF through correlations developed from high-fidelity computational fluid dynamics (CFD) results. To enable further future flexibility for Hi2Lo informed modelling, the option to calibrate correlated values to high-fidelity simulation results through an additional input has also been implemented.

Subject Added Entry-Topical Term  

Heat transfer.

Subject Added Entry-Topical Term  

Physics.

Subject Added Entry-Topical Term  

Nuclear reactors.

Subject Added Entry-Topical Term  

Sodium.

Subject Added Entry-Topical Term  

Homogenization.

Subject Added Entry-Topical Term  

Eigenvalues.

Subject Added Entry-Topical Term  

Energy.

Subject Added Entry-Topical Term  

Feedback.

Subject Added Entry-Topical Term  

Data exchange.

Subject Added Entry-Topical Term  

Geometry.

Subject Added Entry-Topical Term  

Hydraulics.

Subject Added Entry-Topical Term  

Hydraulic engineering.

Subject Added Entry-Topical Term  

Nuclear engineering.

Subject Added Entry-Topical Term  

Thermodynamics.

Added Entry-Corporate Name  

North Carolina State University.

Host Item Entry  

Dissertations Abstracts International. 85-05B.

Host Item Entry  

Dissertation Abstract International

Electronic Location and Access  

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Control Number  

joongbu:643987