자료유형  

 학위논문

Control Number  

0016933628

International Standard Book Number  

9798379564971

Dewey Decimal Classification Number  

539.76

Main Entry-Personal Name  

Gonzalez, Evan S.

Publication, Distribution, etc. (Imprint  

[S.l.] : University of Michigan., 2023

Publication, Distribution, etc. (Imprint  

Ann Arbor : ProQuest Dissertations & Theses, 2023

Physical Description  

1 online resource(184 p.)

General Note  

Source: Dissertations Abstracts International, Volume: 84-12, Section: B.

General Note  

Advisor: Kiedrowski, Brian C.

Dissertation Note  

Thesis (Ph.D.)--University of Michigan, 2023.

Restrictions on Access Note  

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

Restrictions on Access Note  

This item must not be added to any third party search indexes.

Summary, Etc.  

요약This dissertation develops methods to make time-dependent Monte Carlo transport calculations for reactor analysis more tractable. For the first time, the Transient Multi-Level (TML) method is applied to a Monte Carlo transport solver to offload some of the computational burden to lower-order Coarse Mesh Finite Difference (CMFD) and Exact Point Kinetics Equations (EPKE) solvers. The method is implemented in the production-level Monte Carlo code Shift and verified with select 2D transient events from the C5G7-TD reactor benchmark. It is shown that, as compared to other quasi-static methods, the TML reduces both the stochastic noise inherent to the Monte Carlo solver, and the number of Monte Carlo evaluations needed to simulate the transient. A step reactivity insertion for a 3D dual-purpose used nuclear fuel canister was also modeled with approximate fuel temperature Doppler broadening to stress the robustness of the method for large asymmetric configurations. Two techniques for acceleration of the Monte Carlo TML implementation are also explored: parallel- in-time integration and correlated sampling for fission source perturbations. A serial implementation of the parareal algorithm was investigated as a novel acceleration scheme between TML levels. The method converged very quickly for all cases in less than five parareal iterations with projected speedup factors (upon a parallel implementation) ranging from 1.5-8 for the evaluated problems. For correlated sampling, a fission source weighting technique for estimating multiple k-eigenvalue perturbation tallies for a single random walk was extended to general Monte Carlo tallies and shown to be a good approximation for spatially-uniform perturbations. These perturbation tallies can then be used as input for the CMFD and EPKE solvers and serve as a coarse prediction of the propagated Monte Carlo solution.

Subject Added Entry-Topical Term  

Nuclear engineering.

Subject Added Entry-Topical Term  

Thermodynamics.

Index Term-Uncontrolled  

Reactor kinetics

Index Term-Uncontrolled  

Monte Carlo solution

Index Term-Uncontrolled  

Quasi-static methods

Index Term-Uncontrolled  

Parareal algorithm

Added Entry-Corporate Name  

University of Michigan Nuclear Engineering & Radiological Sciences

Host Item Entry  

Dissertations Abstracts International. 84-12B.

Host Item Entry  

Dissertation Abstract International

Electronic Location and Access  

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Control Number  

joongbu:643495