An Interval Approach for Robust Control of a Large PHWR with PID Controllers

A nuclear reactor exhibits changing behavior with variation in reactor power. Further, uncertainties in the measurement of the actual power produced by the reactor, the heat transfer from the fuel to the coolant and the reactivity change due to the change in the fuel and coolant temperatures and condition of the core, make it necessary to adopt a robust control approach for design of control systems for such plants. In this paper a 540 MWe Indian PHWR consisting of 14 zones has been modeled using inexact models incorporating bounded parametric variations in power, heat transfer from the fuel to the coolant and temperature coefficients of reactivity of fuel and coolant. These inexact models are then used to obtain a robust and optimal PID controller gains for controlling the reactor power with specified time response under parametric variations, using an interval approach. The methodology is established with credible MATLAB simulations.