Study on Gray code control rod position indicator

A new control rod position indicator for water reactors, the Gray code cont rol rod position indicator, is introduced in this paper. The indicator cons ists of a primary winding, several grouped secondary coils and one coding b ar, which is composed of m sections of magnetic core and q sections of non- magnetic portions arranged alternately on the longitudinal axis of the rod housing. As the control rod is withdrawn, the coding bar passes the coils a nd changes their output signals. By picking up and processing the signals, n bits of Gray code, which are related to the rod position, are obtained. C ompared with a combination coding rod position indicator, each Gray code in dicates a step. Compared with the coil-coding rod position indicator, the G ray code rod position indicator is simpler in structure and more reliable i n operation, so it is a good control rod position indicator for water react ors. (C) 1998 Elsevier Science S.A. All rights reserved.