Neutronic Simulation of Fuel Assembly Vibrations in a Nuclear Reactor
Artikel i vetenskaplig tidskrift, 2020

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.

time domain modeling

Neutron noise

neutron diffusion approximation

frequency domain modeling

fuel assembly vibrations


A. Vidal-Ferrandiz

Universitat Politecnica de Valencia (UPV)

A. Carreno

Universitat Politecnica de Valencia (UPV)

D. Ginestar

Universitat Politecnica de Valencia (UPV)

Christophe Demaziere

Chalmers, Fysik, Subatomär, högenergi- och plasmafysik

G. Verdu

Universitat Politecnica de Valencia (UPV)

Nuclear Science and Engineering

0029-5639 (ISSN)

Vol. 194 11 1067-1078

Core monitoring techniques and experimental validation and demonstration (CORTEX)

Europeiska kommissionen (EU) (EC/H2020/754316), 2017-09-01 -- 2021-08-31.


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