Neutronic Simulation of Fuel Assembly Vibrations in a Nuclear Reactor

[EN] The mechanical vibrations of core internals such as fuel assemblies (FAs) cause oscillations in the neutron flux that require in some circumstances nuclear power plants to operate at a reduced power level. This work simulates and analyzes the changes of the neutron flux throughout a nuclear cor...

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Detalles Bibliográficos
Autores: Vidal-Ferràndiz, Antoni|||0000-0001-5449-7356, Carreño, Amanda|||0000-0003-2302-1157, Ginestar Peiro, Damián|||0000-0003-1243-6648, Verdú Martín, Gumersindo Jesús|||0000-0001-5098-080X, Demazière, C.
Tipo de recurso: artículo
Fecha de publicación:2020
País:España
Institución:Universitat Politècnica de València (UPV)
Repositorio:RiuNet. Repositorio Institucional de la Universitat Politécnica de Valéncia
Idioma:inglés
OAI Identifier:oai:riunet.upv.es:10251/176368
Acceso en línea:https://riunet.upv.es/handle/10251/176368
Access Level:acceso abierto
Palabra clave:Neutron noise
Fuel assembly vibrations
Neutron diffusion approximation
Time domain modeling
Frequency domain modeling
INGENIERIA NUCLEAR
MATEMATICA APLICADA
Descripción
Sumario:[EN] The mechanical vibrations of core internals such as fuel assemblies (FAs) cause oscillations in the neutron flux that require in some circumstances nuclear power plants to operate at a reduced power level. This work simulates and analyzes the changes of the neutron flux throughout a nuclear core due to the oscillation of a single FA without considering thermal-hydraulic feedback. The amplitude of the FA vibration is bounded to a few millimeters, and this implies the use of fine meshes and accurate numerical solvers due to the different scales of the problem. The results of the simulations show a main oscillation of the neutron flux with the same frequency as the FA vibration along with other harmonics at multiples of the vibration frequency much smaller in amplitude. Also, this work compares time domain analysis and frequency domain analysis of the mechanical vibrations. Numerical results show a close match between these two approaches for the fundamental frequency.