Identification of sources of excitation of acoustic standing waves in the VVER-440 reactorunit

Abstract

Results of special measurements of coolant pressure oscillations in primary loops on unit No 3 of Novovoronezh NPP with VVER-440 are presented. Acoustical models and calculating algorithms for determinations of frequencies of acoustic standing waves (ASW) are designed. Models based on the Method of Electro-Acoustic Analogies gives a sensible interpretation of ASW sources. The calculated values of ASW frequencies for each acoustic element and for their compositions are presented. Identifying the sources of ASW in the first circuit held at all stages of the start-up power. Analysis of the results of comparison ASW rate with the measurement data of the main equipment vibration revealed a number of modes in which resonance of vibration with ASW occurs. Shown that developed approach can be used both in normal operation and in emergency modes for research and development of vibration - acoustic certification of reactor facilities; Improvements of process control and computer codes.