Implementation of Reactor Control Rod Position Sensing/Display Using a VLSI Chip
Imbaby Ismail Mahmoud · Advances in computer and electrical engineering book series · 2016
The chapter describes the use of CPLDs and FPGAs devices in Nuclear Power Plant (NPP) Instruments. The design, simulation, implementation and test of a reactor control rod position sensing electronic unit intended as a replacement of the outdated Russian type in old power reactors is presented. The signals are generated from12 ring-shaped pair of inductively coupled coils surrounding the reactor moving rod. The implementation involves both analog and digital design. The designed digital circuit has 12 TTL outputs working in a 1-out-of-12 mode, excluding both double [2-out-of-12] and no-output state. To avoid a flickering display during transition between two neighboring positions, some sort of hysteresis is implemented. One time this hysteresis is implemented through a state machine deriving up/down counter. The state machine is synthesized targeting a Xilinx Spartan XL device. To reduce the possibility of power failure effects, another circuit consists of combinatorial logic and implemented in CPLD is presented. However, energy harvesting methods in NPPs can support counter based design.