Vibration measurements at KNK II

For the development of surveillance techniques, vibration measurements have been performed at the sodium cooled fast reactor KNK II. For this purpose the signals of neutron detectors, sodium pressure gauges, displacement transducers and strain gauges, some of them being installed within the core, have been analyzed by means of noise analysis methods. The power spectral densities of the neutron flux and the sodium pressure show distinct correlated peaks indicating vibrations of core internals