Document: NUREG-0800
Document ID: 8ec28e2c-84e9-408b-afcb-1838fbfe7efc
Document Type: srp
Title: ENGINEERED SAFETY FEATURE VENTILATION SYSTEM
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0705/ML070550041.pdf
Revision Date: 2023-06
Chapter: 9
Section ID: 9.4.5
CFR Part: 
CFR Title: 

Content:
i.e., loss of offsite electric power system concurrent with reactor trip and unavailability of the onsite emergency ac electric power system). A station blackout analysis covering a minimum acceptable duration (either to “withstand” the event until an alternate ac source and shutdown systems are lined up for operation or to “cope” with it for its duration, including the associated recovery period) is required. RG 1.155 provides guidance for complying with station blackout requirements. Regardless of the extent to which the ESFVS is expected to function to maintain suitable environmental conditions during a station blackout event, equipment that is necessary to accomplish core cooling, maintenance of appropriate containment integrity, and other functions that constitute “withstanding” and/or “coping” during the event should be capable of functioning under the expected environmental conditions associated with the event. The station blackout analysis is therefore verified to appropriately address the potential failures of equipment/systems during the event (e.g., loss of or degraded operability of the ESFVS, as appropriate), the expected environmental conditions associated with the event, the operability and reliability of equipment necessary to cope with the event under the expected environmental conditions, and the habitability of plant areas requiring operator access during the event and associated recovery period. Those portions of the ESFVS that are identified in a coping analysis as necessary to support the functioning of equipment required to cope with the event or recovery therefrom are verified to be of sufficient capacity and capability to provide such support. Meeting the requirements 10 CFR 50.63 provides assurance that necessary operator actions can be performed and that necessary equipment will be functional under the expected environmental conditions during and following a station blackout, thereby ensuring that the core will be cooled