Development of a Method for Calculating ASW Frequencies in VVER-440 Pressurizer

In this paper, a digital acoustic model of pressurizer (DAMP) for the VVER-440 is verified. A new method for calculating acoustic standing waves (ASW) generated in the pressurizer as a whole, its parts and pipelines connected to it has been developed and the calculated values of the ASW frequencies were consistent with the measured readings of the pressure pulsation sensors (PPS) signals. Calculations were made according to the formula of Thomson using the electroacoustic analogy method using the acoustic compliance and acoustic mass of the pressurizer and various combinations of pipelines connected to it. It is concluded that the calculated ASW frequencies depend on the operating conditions of the installation and can fall into the same frequency band of the pressurizer as a whole, its parts and associated pipelines. At the same time, the acoustic properties of the compensator and various combinations of pipelines connected to it turned out to be the same as those of a set of Helmholtz resonators operating at the same time.