Thermoacoustic instability of the coolant in a water-moderated core

The physical model, technique and program were developed for computation of TAI borders of the coolant in a WWER core. They are based on the analysis of the conduct of condensing bubbles in stream volume, that defined by period of acoustic oscillations. On the basis of variations accounts the technique of an operative estimation of a WWER core condition is reasonable. It does not require bulky numerical accounts. The verification of settlement methods at the qualitative and quantitative level was carried out. It is shown the quite satisfactory co-ordination of settlement and experimental data. The analysis of operation experience of working power units with WWER- 1000 is submitted. As a result it is established that reactor is steady in working modes (including nominal). TAI of the coolant can arise in certain transitive or emergency operation. The existence conditions of these modes are determined and the recommendations for their elimination at operation of NPP's with WWER are reasonable