Design modifications of Instrumentation and Control System of future FBRs based on feedback from safety review and commissioning experience

The purposes of Instrumentation and Control systems are to assist the operator in controlling the plant at the specified power level, monitor the plant and warn of deviations from normal conditions, prevent accidents by carrying out independent automatic safety and control actions, and mitigate consequences of an accident automatically. Design of I&C for PFBR is done in line with 'AERB Safety Criteria for design of fast reactors' and to suit operational and environmental conditions. I & C of PFBR uses hybrid system consisting of computer based control system and hard wired system. Safety critical systems are built using triple redundant computer systems and / or hardwired systems. Safety related systems use dual redundant VME based real time computers and non safety class I & C systems are built using predeveloped systems. For future FBR designs, thrust is given to align with Gen IV requirements and our experiences with safety review and commissioning also demands design enhancements. The core temperature monitoring probe is designed with three thermocouples for each fuel sub-assembly. Also the thermocouple channels will have indigenously developed hardware. Indigenisation has resulted in economic benefits. Triple redundant computer systems will have diverse computers running software developed by different agencies. The non-safety systems will use wireless interface for signal and command transfer. (author)