Design of Central Sub Assembly Temperature Monitoring System for Prototype Fast Breeder Reactor

The Central Sub Assembly Temperature Monitoring (CSATM) System for 500 MWe Prototype Fast Breeder Reactor (PFBR) is a safety critical system. It is an independent, standalone, hardwired and diversified system to neutronic parameters. The detection of integrity of the subassembly plays a major role, because of high power density and compact core structure of PFBR fuel. To achieve this, CSATM system is provided for the measurement and detection of overshoot for Central Sub Assembly temperature. It protects the reactor from various incidents such as transient overpower at low power and high power, blockage of coolant, pipe rupture etc. CSATM system with triple modular redundancy is employed to measure the central sub-assembly outlet temperature (θ_CSA) and safety action will be initiated if temperature reaches beyond SCRAM threshold level. (author)