Lambda modes comparison for different approximations of the neutron transport equation: Diffusion, SN and SP3

[EN] The methods presented in this paper solve the Simplified Spherical Harmonics approximation to the mul- tidimensional neutron transport equation. 1D, 2D and 3D systems were modeled with Cartesian geome- try using the finite difference method to discretize the spatial variables. The method is abl...

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Detalhes bibliográficos
Autores: Morató-Rafet, Sergio, Kochunas, B., Larsen, E. W., Downar, T., Miró Herrero, Rafael|||0000-0003-1012-0869, Verdú Martín, Gumersindo Jesús|||0000-0001-5098-080X
Formato: artículo
Fecha de publicación:2021
País:España
Recursos:Universitat Politècnica de València (UPV)
Repositorio:RiuNet. Repositorio Institucional de la Universitat Politécnica de Valéncia
Idioma:inglés
OAI Identifier:oai:riunet.upv.es:10251/184702
Acesso em linha:https://riunet.upv.es/handle/10251/184702
Access Level:acceso abierto
Palavra-chave:Simplified spherical harmonics
SP3
Multigroup
Finite difference method
Multiple eigenvalues
Boundary conditions
Lambda modes
INGENIERIA NUCLEAR
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Descrição
Resumo:[EN] The methods presented in this paper solve the Simplified Spherical Harmonics approximation to the mul- tidimensional neutron transport equation. 1D, 2D and 3D systems were modeled with Cartesian geome- try using the finite difference method to discretize the spatial variables. The method is able to simulate any energy group discretization, including up-scattering terms. The Krylov Shur method was used to cal- culate the solution of the steady-state equation by solving a generalized eigenvalue problem. This methodology has the capability to calculate any number of eigenfunctions. A formulation review of the Simplified Spherical Harmonics is explained in this work, as well as, a study of the boundary condi- tions for different approaches of the finite difference method. The results calculated by this methodology are compared with the discrete ordinates and diffusion approximation methods, all of them, using the same spatial discretization in order to show the different accuracy of each method without influence of the method used for discretizing the spatial variable. The results show the validity of each method for different benchmark problems.