Design and development of FPGA based safety logic units for fuel handling controls of 700 MWe PHWRs

In the existing 220 and 540 MWe PHWRs, Fuel Handling Manual and Safety Logic is implemented by interconnecting standard logic blocks using CMOS ICs. Because of large number of safety related interlocks, the density of the wiring is so enormous that it becomes difficult to troubleshoot in case of any fault or to carry out any further modifications. This paper discusses the implementation of Fuel Handling safety logic for 700 MWe PHWRs using high-density programmable devices to reduce wiring and to improve the reliability and maintainability. The fault annunciation and indication of healthiness of hardware are also incorporated. (author)