Enhancing Seismic Resilience and Dynamic Performance in NPPs With VVER-1200

In this paper, we investigate the cause-and-effect relationships governing the operational dynamics of the reactor plant (RP) and changes in noise signals. Focusing on anomalous states in the VVER-1200 RP, exemplified by power units No. 1 and 2 at Novovoronezh NPP-2, we introduce a method for determining the acoustic bandwidth. This method establishes a correlation between experimentally extrapolated and calculated Acoustic Standing Wave (ASW) frequencies. Resonances in oscillatory processes reveal accelerated wear in primary circuit equipment. We emphasize the necessity of pressure pulsation sensors (PPS) in the noise measurement system for precise dynamic load evaluation during NPP operation and earthquakes. Experimental data collected during commissioning at new NPP power units, under realistic equipment conditions, offers critical insights. The study highlights the potential risk of a beyond-design-basis accident, particularly during local earthquakes. These findings underscore the significance of comprehensive analyses and the integration of practical, experimental data to inform safety measures and design considerations within NPP.