The safe operation of a nuclear power plant depends on the reliability and safety of the reactor plant, which in turn requires careful monitoring of the equipment at the manufacturing and operation stages. This monograph critically examines the fundamental effects of hydrodynamic and vibration load formation on the modern power unit of the VVER-1200 nuclear power plant, which is originally designed in Russia, as well as the causes and main sources of vibration in the main circulation loop and their energy contribution. Practical examples are used to explain how vibration stress can be reduced and the hydrodynamic status of the circuit improved. Current research on the vibroacoustics of some non-Russion nuclear reactors is also included.