Two-stage modelling of hexagonal fuel assemblies vibration considering mechanical nonlinearities

• Published in: Progress in nuclear energy (New series) Vol. 138; p. 103825
• Main Authors: Zeman, V., Dyk, Š., Hlaváč, Z.
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01.08.2021; Elsevier BV
• Subjects: Assemblies; Assembly; Coolant pressure pulsations; Couplings; Friction; Friction vibration; Fuel assembly; Fuels; Grooves; Mathematical models; Mechanical properties; Nonlinear vibration; Nonlinearity; Nuclear fuels; Nuclear reactor; Nuclear reactor components; Pressure vessels; Vibration; Friction vibration; Fuel assembly; Nonlinear vibration; Coolant pressure pulsations; Nuclear reactor
• ISSN: 0149-1970; 1878-4224
• DOI: 10.1016/j.pnucene.2021.103825

The paper presents a complex modelling concept for the nuclear fuel assembly vibration caused by the coolant pressure pulsations generated by the main circulation pumps. The method is based on the two-stage modelling with the reactor’s global model at the first stage and the detailed model of the particular fuel assembly at the second stage. This approach allows respecting all the relevant mechanical nonlinearities — clearances and friction in the key-groove couplings between the reactor core barrel and the pressure vessel and the internal impact or the friction interaction of the fuel assemblies. Numerical simulations allow better interpretation of monitoring data concerning the fuel burn-up. •Two-stage model: reactor (1st stage) and fuel assembly (2nd stage).•Fuel assembly model with inner nonlinearities.•Friction/impact contact in key-groove couplings at the reactor stage.•Excitation by pressure pulsations of coolant.•Burnup of the chosen fuel assembly is considered.