FEEDFORWARD DIGITAL CONTROL OF NUCLEAR REACTORS.

Practical automatic controllers for the position of control rods have been developed using stepper motors with the two-fold objective of minimizing reactor power deviations about the set point in a mean square sense and allowing changes in set point to be made in a rapid, accurate and stable manner. However, these systems being basically of the feedback type, have certain inherent drawbacks such as instability at higher values of gain and the presence overshoots and undershoots in their step responses. A relatively new technique, the feedforward control technique, has been successfully incorporated in the design of an analog positioning servo-mechanism and is currently being employed in the design of digital control systems as well. This paper is concerned with the development of a digital control system for reactor control using the feedforward technque. A scheme employing this technique is proposed and analysed particularly from the point of view of stable operation at very high values of system gains.