Auto-tuning PID Controller for NuScale Nuclear Reactor using Point Reactor Kinetics Model Simulator

Nuclear power plants are one of the main focuses of national research in Indonesia for the 2020-2024 period, which aims to develop the first nuclear power plant prototype. As a step to support this goal, this paper introduces a model of the NuScale reactor that can be combined with a control prototype and application of an auto-tuning proportional- integral-derivative (PID) control strategy that is applied to the reactor power control system. Non-linear modeling is arranged in a state-space model that describes the parameters of the reactor primary loop system. State-space computing is implemented in the Laboratory Virtual Instrumentation Engineering Workbench (LabVIEW) software which can be combined with attractive simulator devices according to the technology in the NuScale reactor. PID auto-tuning control is used as a power controller by adjusting the reactivity of 4 types of control rods in the reactor core. PID control parameter is set based on an algorithm that identifies the ultimate gain, ultimate period, dead time, and time constant based on Ziegler and Nichols’ heuristic methods. Results of verification with NuScale reactor data that have obtained design approval from the United State Nuclear Regulatory Commission (NRC) show error values below 1% on main parameters such as power, neutron flux, fuel temperature, coolant temperature, reactor pressure, and coolant flow. Reactor control simulation is run using step signal input and ramp signal in a load-following mode in the power range of 90% full power to 100% full power. The result of comparison with manual PID control shows that auto-tuning PID shows better performance and stability in maintaining reactor power in start-up and load-following operation.