Water level measurement and control in steam generators of WWER-1000 nuclear power plants

A method is suggested for measuring the level and steam power in steam generators of WWER-1000 nuclear power plants. It enables, for steam generator level control, to eliminate components that contribute high uncertainty to the measurement as well as orifice gauges deteriorating the plant performance economy. This contributes to the reliability of the level control circuit and to the control quality, particularly during low unit power modes. The measuring method is based on physical laws controlling the phenomena occurring in the steam generator. These include the dependence of the steam content in the steam-water mixture on the steam power of the generator. This dependence can be employed for attaining a shift of the desired level value during a power change directly in the recorded level signal as well as for determining the amount of steam generated. The quality of the control making use of this level and steam power measurement technique was verified over a wide region on a unit dynamics model. (Z.M.)