Generation of isotropic and anisotropic scattering cross section for boltzmann-fokker-planck equation via extrapolation exponential function and minimized RMS errors = 외삽 지수함수와 RMS 에러를 사용한 BFP equation 의 등방성, 이방성 산란 단면적 생산

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Handling highly anisotropic scattering of fast neutrons with conventional methods usually means that high order Legendre expansions are necessary to obtain correct angular fluxes. This drawback in standard transport calculations is avoided by applying the Boltzmann-Fokker-Planck (BFP) equation which has been used in both neutral and charged-particle transport problems. Previously, Caro and Ligou, and Morel have introduced Fokker-Planck decomposition methods, which decompose elastic scattering cross section into forward-peaked and smooth components. A new method for decomposing scattering cross sections for Boltzmann-Fokker-Planck equation is presented. We start from the basic data σ(μ, E) (given by ENDF/B-VI) to get more correctly determined BFP data. In this method, we use Legendre expansion for smooth component and exponential function which Caro and Ligou used for forward-peaked component. In addition, by using RMS errors and an extra degree of freedom $\sigma_{ext}$, we conserve both moments and scattering cross section. To show the superiority of the new decomposition method, we evaluate generated BFP data with $^{238}U$ and $^{235}U$ multi-slab problems.
Advisors
Cho, Nam-Zinresearcher조남진researcher
Description
한국과학기술원 : 원자력양자공학과,
Publisher
한국과학기술원
Issue Date
2002
Identifier
174274/325007 / 020003127
Language
eng
Description

학위논문(석사) - 한국과학기술원 : 원자력양자공학과, 2002.2, [ [iii], 44 p. ]

Keywords

decomposition; anisotropic; isotropic; BFP Equation; scattering cross section; 등방성; 이방성; 산란단면적

URI
http://hdl.handle.net/10203/49442
Link
http://library.kaist.ac.kr/search/detail/view.do?bibCtrlNo=174274&flag=dissertation
Appears in Collection
NE-Theses_Master(석사논문)
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