Spatial Power Control of Singularly Perturbed Large Nuclear Reactor

Abstract

Controlling of large nuclear reactors is a challenging task due to simultaneouspresence of both the slow and the fast varying dynamic modes. This paper presents the designof linear quadratic regulator for spatial power control of a large Advanced Heavy Water Reactor(AHWR). The AHWR system is represented by 90 first order nonlinear differential equationswith 5 input and 18 output variables. After linearization, the original ill-conditioned systemof AHWR is represented into standard singularly perturbed two-time-scale form and then it isdecomposed into two comparatively lower order subsystems, namely, ‘slow’ subsystem and ‘fast’subsystem of orders 73 and 17 respectively. Two individual optimal controllers are developed forboth the subsystems and then a composite controller is obtained for original higher order system.This composite controller is applied to the vectorized nonlinear model of AHWR. From dynamicsimulation of the nonlinear model of the reactor in representative transients, the suggestedcontrol scheme is found to be superior to other methods.