Knowledge of reactor internal vibration behaviour for building expert system

Vibrations of reactor internals are studied with respect to noise diagnostics and the building of a diagnostic expert system. The basic theory is presented along with the first numerical results on the behaviour of the support cylinder represented by a cylindrical shell. The results show that level changes in the system pressure vessel-support cylinder have marked effect on the frequency spectrum of the support cylinder vibrations, which might be used to indicate the water level in the core during small LOCA and ATWS accidents and might form part of a diagnostic expert system. (author)