Justification of level values in steam generators with V-392m reactor unit during normal operation and normal operation disturbance

Abstract

The ability to carry the load during transients without achieving the operating conditions of the safety and emergency control action of the reactor is called the dynamic stability of the NPP power unit. Water level control in steam generators RU VVER-1200 (V-392M) is carried out to maintain a balance between steam removal, purging and water supply. A change in the water level in the steam generator caused by transients can lead to the achievement of technological protection and blocking settings, followed by the shutdown of the main circulation pump and a reduction in load. An analysis of the commissioning tests of the Novovoronezh, Leningrad and Belorussian NPP power units, as well as the shutdowns of the main equipment due to changes in the level in the steam generators, allowed us to identify possible ways to increase the dynamic stability of the VVER-1200 power units. Maintaining the nominal water level in the steam generator makes it possible to prevent steam from entering the turbine with an increased humidity of more than 1%. There are real perspectives for VVER-1200 power units dynamic stability improving by upgrading the shut-off valves at the steam generator power supply unit with increased performance and appropriate adjustments to the water level settings in the steam generator. Increasing the dynamic stability of the VVER-1200 power units will make a significant additional contribution to the economic attractiveness of the improved nuclear power plant design of domestic design.