摘要
Destructions at Fukushima Daiichi NPP （nuclear power plant） caused by earthquake have shown that design level of seismic influences on the equipment has been exceeded. The accident demonstrated the need for stricter regulations to ensure the seismic resistance of NPP and the need to develop and implement additional anti-seismic procedures in the course of their operation. To proof seismic reliability of NPP systems and components must be made special studies of logarithmic decrement of systems NPP and components. The correct definition of coolant thermodynamics parameters and acoustic parameters are necessary to evaluate logarithmic decrement of coolant systems NPP and their components and consequently for providing of NPP seismic reliability. The proof of presence of a gas phase in the coolant inside reactor is of great importance for practice because of its influence on coolant acoustical parameters and consequently on range of frequency of seismic-acoustical resonance type interaction. Results are obtained by using of known methods in oscillation theory, general acoustics, thermodynamic, electro-mechanical analogies. As well as using experimental data obtained from the vibration dynamical controls reactor WWER-1000.
