Robust Control of Nuclear Reactors with Proportional—Integral-Derivative (PID) Controllers: The Fractional Order (FO) and Interval Approaches

Control of a nuclear reactor poses a challenge to a control-system designer due to the inherent nonlinear and a time varying nature of the associated dynamics which changes with the power level and the depletion level of the radio-active fuel in the reactor core. A constraint on the rate of rise of reactor power poses an additional challenge restricting the operation of a Nuclear Power Plant (NPP) mostly as a base load station. Conventional reactor control approaches aim to achieve a stable reactor period around a designated reactor power level—which is usually 100% Full Power (FP), with refinements like flux-tilt control and zonal power level variations within a narrow range using reactivity devices distributed across the reactor core. A bulk power controller is invoked either to raise the reactor power to a steady operational level or during a sharp reduction, known as a step-back and seldom in a demand following mode.