Control system design for a pressure-tube-type supercritical water-cooled nuclear reactor via a higher order sliding mode method

Nuclear power plants exhibit non-linear and time-variable dynamics. Therefore, designing a control system that sets the reactor power and forces it to follow the desired load is complicated. A supercritical water reactor(SCWR) is a fourthgeneration conceptual reactor. In an SCWR, the non-linear dynamics of the reactor require a controller capable of controlling the nonlinearities. In this study, a pressure-tube-type SCWR was controlled during reactor power maneuvering with a higher order sliding mode, and the reactor outgoing steam temperature and pressure were controlled simultaneously. In an SCWR, the temperature, pressure, and power must be maintained at a setpoint(desired value) during power maneuvering.Reactor point kinetics equations with three groups of delayed neutrons were used in the simulation. Higher-order and classic sliding mode controllers were separately manufactured to control the plant and were compared with the PI controllers specified in previous studies. The controlled parameters were reactor power, steam temperature, and pressure. Notably, for these parameters, the PI controller had certain instabilities in the presence of disturbances. The classic sliding mode controller had a higher accuracy and stability; however its main drawback was the chattering phenomenon. HOSMC was highly accurate and stable and had a small computational cost. In reality, it followed the desired values without oscillations and chattering.