Control of the nuclear steam generators using adaptive dynamic sliding mode method based on the nonlinear model

The water level control problem of steam generators has been a main cause of unexpected shutdowns of nuclear power plants which must be considered for plant safety and availability. The control problem is challenging, especially at low power levels due to shrink and swell phenomena and flow measurement errors. Moreover, the dynamics of steam generator vary as the power level changes. Therefore, it is necessary to improve the water level control system of SG. In this paper, at the first a nonlinear model based on the fundamental conservation equations for mass, energy and momentum is presented for the nuclear steam generator which is validated with other computer programs and experimental results and then, an adaptive dynamic sliding mode control method is applied for the level control problem of U-tube steam generators based on the presented nonlinear model. The proposed method exhibits the desired dynamic properties during the entire output tracking process independent of perturbations. Simulation results are presented to demonstrate the effectiveness of the proposed controller in terms of performance, robustness and stability. Simulation results confirm the improvement in transient response obtained by using the proposed controller.