STEAM SYSTEM AND FEEDWATER SYSTEM FAILURES

The adequacy of the EGCR steam and feedwater systems for continued heat removal from the core was assessed for the following accidents: steam line failures, steam generator internal failures, and feedwater system failures. The reaction of the reactor coolant blowers and vessel cooling compressors to steam- helium mixtures was evaluated. The steam generator isolation systems are described. The containment system was found to be adequate to prevent activity release to the atmosphere in the event of all credible steam line or feedwater system failures. The design of the drum water level automatic isolation system does not prevent activity release during certain credible steam generator failures, however, this activity is released at the top of the plant stack and does not result in a dose which exceeds the acceptable yearly exposure. (M.C.G.