Control system design for the once-through steam generator of lead–bismuth cooled reactor based on classical control theory

The performance of once-through steam generator (OTSG) steam pressure control is directly related to the safe and stable operation of the lead–bismuth cooled reactor system. In this paper, the OTSG of a small lead–bismuth cooled reactor is investigated and its feedwater controller is designed based on classical control theory. A nonlinear OTSG model is first established based on the movable boundary approach, and a nonlinear feedwater system model is developed based on law of similarity and momentum conservation. Then the corresponding linearized models are obtained. On this basis, two control strategies are proposed for regulating the feedwater valve and adjusting the steam valve, and the controller is designed based on the linearized model using the analytical method. Finally, the controller is simulated using a high-order nonlinear model, which shows that both proposed control strategies can effectively control the steam pressure.