A time and frequency domain analysis of the effect of vibrating fuel assemblies on the neutron noise
Journal article, 2019

The mechanical vibrations of fuel assemblies have been shown to give rise to high levels of neutron noise, triggering in some circumstances the necessity to operate nuclear reactors at a reduced power level. This work analyses the effect in the neutron field of the oscillation of one single fuel assembly. Results show two different effects in the neutron field caused by the fuel assembly vibration. First, a global slow variation of the total reactor power due to a change in the criticality of the system. Second, an oscillation in the neutron flux in-phase with the assembly vibration. This second effect has a strong spatial dependence that can be used to localize the oscillating assembly. This paper shows a comparison between a time-domain and a frequency-domain analysis of the phenomena to calculate the spatial response of the neutron noise. Numerical results show a really close agreement between these two approaches.

Fuel assembly vibrations

Time domain

Neutron diffusion

Frequency domain

Neutron noise


Antoni Vidal

Polytechnic University of Valencia (UPV)

A. Carreño

Polytechnic University of Valencia (UPV)

Damian Ginestar

Polytechnic University of Valencia (UPV)

Christophe Demaziere

Chalmers, Physics, Subatomic and Plasma Physics

Gumersindo Verdu

Polytechnic University of Valencia (UPV)

Annals of Nuclear Energy

0306-4549 (ISSN)


Core monitoring techniques and experimental validation and demonstration (CORTEX)

European Commission (Horizon 2020), 2017-09-01 -- 2021-08-31.

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Signal Processing

Other Electrical Engineering, Electronic Engineering, Information Engineering



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