Document: NUREG-0800
Document ID: 010ad62f-cd7b-4f06-9f81-a781faf5701b
Document Type: srp
Title: ENGINEERED SAFETY FEATURE VENTILATION SYSTEM
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0520/ML052070560.pdf
Revision Date: 2023-06
Chapter: 9
Section ID: 9.4.5
CFR Part: 
CFR Title: 

Content:
release of radioactive materials in gaseous effluents during normal reactor operation, including anticipated operational occurrences. Regulatory Guides 1.140 and 1.52 present methods acceptable to the Commission staff with regard to design, testing, and maintenance criteria for air filtration and adsorption units of normal ventilation exhaust systems and of engineered safety feature atmosphere cleanup systems used in light-water-cooled nuclear power plants. Atmosphere cleanup systems are included in the design to reduce the quantities of radioactive materials in gaseous effluents released to the environment. Meeting these requirements provides assurance that release of radioactive materials entrained in gaseous effluents will not exceed the limits specified in 10 CFR Part 20 for normal operation and anticipated operational occurrences.57 6. Compliance with 10 CFR 50.63 requires a demonstration that the plant has the capability to withstand and recover from a station blackout (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. Regulatory Guide 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