Identification of seismic structures, systems and components of PHEC system of Fast Breeder Test Reactor

The reactor shutdown is followed by power decay and the decay heat removal is carried out by different decay heat removal (DHR) systems based on the plant configuration. In FBTR, normal mode of DHR is by the primary and secondary sodium loops and through steam generators (SG) with trap doors of the SG casing open. For DHR by normal mode, at least one primary and secondary loop should be available. Pre-Heating and Emergency Cooling (PHEC) is an engineered safety system for DHR in situations where sodium flow cannot be maintained in primary as in case of non-availability of both the primary sodium pumps or due to leak outside the reactor double envelope. This paper presents the methodology adopted for identification of seismic structures and components (SSC), the estimation of component fragility for SSC and the system capacity assessment for PHEC. This analysis is carried out as part of seismic re-evaluation of FBTR.