VVER 1000 Pressurizer System and Control Modelling in Dymola

The pressurizer is responsible for controlling the pressure and temperature in the primary circuit of the nuclear power plant. It is basically a pressure vessel, filled partially with water and partially with steam at saturation state. The controlling process can be described by two regimes, either by the self-control regime or by the automatic control regime. This paper is describing the simplified automatic control regime on the model of the pressurizer in the primary circuit of VVER 1000 made in Dymola software with the ClaRa library. Reactor power change and corresponding steam generator power change are the actuators in the simulation. The behaviour of the coolant level and pressure in the pressurizer is simulated in the model and it is then compared with data provided by the supplier of VVER 1000.