Practical experience with primary circuit vibration noise analysis at Paks Nuclear Power Plant

Automatic vibration monitoring systems have been installed for units 1-4 of the PAKS Nuclear Power Plant. During normal operation regular routine measurements are carried out on the units to analyze the changes in the vibration and to forecast the failures. The results of the measurements have been stored for later comparisons and analysis. In parallel with these tests the vibration measurements carried out during course of start up of the unit, have the aim to study the complex movement of the primary circuit, to determine the different forms of movements and to analyse the vibrational behavior of the units at different operational conditions. In relation with these tasks some special vibration measurements had taken place. An overview of normal measurements and some results are given. In connection with the evaluation of the measurements of start up, some eigen-frequencies and modes, representing the global movements of the main equipments were determined. Our efforts concentrate to examine the changes of these vibration characteristics related to the condition of the unit and the parameters of the primary circuit. (author)