Surveillance requirements : need and effectiveness at nuclear power stations

The Tarapur Atomic Power Station has five engineered safeguard systems for : (1) core spray and containment cooling, (2) auto blow-down, (3) primary and secondary containment isolation, (4) emergency ventilation and (5) emergency power supply. The function of each system is explained in brief. Various surveillance checks as stipulated in the technical specifications for each of them and also for reactor protection system, control rod drive system and liquid poison system are given along with a schedule of checks. These checks have revealed the defective components and faults in the scheme and thus helped to rectify them in time. This point is illustrated by relating experiences in this regard. (M.G.B.)