[en] Vibration monitoring and loose parts monitoring during reactor operation take an essential part in an incipient failure detection system. Within this framework extensive measurements of mechanical vibrations of primary components have been accomplished at PWR, BWR and sodium cooled reactors. The application of correlation analysis methods (e.g. auto- and crosspower spectral density formalism) to these experiments leads to a steady-state representation within the frequency domain of the vibrative behaviour of the primary circuit components. A method is presented to compute vibrational power spectral densities (VPSD's) of primary circuit components based on a finite-element representation of the primary circuit. First this method has been applied to the sodium cooled reactor KNK, Karlsruhe. Now a further application is bing developed for a BWR-nuclear power plant. (Auth.)