Plant emergencies reliability issues

Two studies resolved the Unresolved Safety Issue A-44, "Station Blackout." The first siudy, The Reliability of Emergency AC Power Systems in Nuclear Power Plants," when combined uh die lelevant loss-oToffsite-power frequency, provides estimates of station-blackout frequencies lor 18 nuclear power plants and 10 generic designs. The study also identified the design and operational features most important to the reliability of AC power systems. The second study, "Station Blackout Accident Analysis" (NUREG/CR-3226), focused on the relative importance to risk of laiion blackout events and the plant design and operational features that would reduce this risk. 

Since (1) the Nuplex 80+ Advanced Control Complex incorporates adequate and reliable instrumentation for the rapid detection of a Loss-of-Feedwater event by the plant operators and for monitoring the subsequent actions to achieve a safe shutdown, and (2), emergency procedure guidelines are provided for this event, this safety issue is resolved for the System 80+ Standard Design. 

Generic Safety Issue (GSI) II.E.l.l in NUREG-0933 (Reference 1), addresses the TMI-related requirement [10 CFR 50.34(f)(1), Reference 2] that all operating plants and plants under construction re-evaluate their emergency feedwater (EFW) system designs with respect to reliability and availability. 

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