The way the operating conditions of the circuits of nuclear power stations with VVER-1000 reactors affect the reliability of PGV-1000 steam generators

The known causes, kept in the background, for the appearance of cracks in the cold headers of PGV-1000 steam generators, the results of measurements of coolant pressure fluctuations in VVER-1000 reactor installations, the vibrations of various elements of these installations, and also the calculated estimates of the natural frequencies and of the modes of the oscillations are discussed. The effect of the regimes of the circuits in VVER-1000 reactors on the operating reliability of the headers of PGV-1000 steam generators is assessed as is that of the oscillatory characteristics of the mechanical constructions and the coolant.