Document: NUREG-0800
Document ID: ac4cde5a-7464-48b8-9067-860c672cbb68
Document Type: srp
Title: STATION BLACKOUT
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0705/ML070550061.pdf
Revision Date: 2023-06
Chapter: 8
Section ID: 8.4
CFR Part: 
CFR Title: 

Content:
dices A and B to RG 1.155, as described in Subsection III.3 below. Except for passive ALWR plant designs (such as the AP1000), an AAC power source that is fully capable of powering one complete set of normal shutdown loads should be the preferred method of demonstrating compliance with 10 CFR 50.63 (Ref. 25) for new applications licensed under 10 CFR Part 52 (Ref. 5). These plants cannot use the ac-independent approach (i.e., coping with battery power). The determination of the plant’s ability to cope with an SBO should be based on the following general criteria and baseline assumptions (Refs. 7 and 38): A. Because of the presence of substantial decay heat, events initiated from 100-percent power bound the potential for core damage from an SBO. Therefore, the coping analysis should be performed assuming that the SBO event occurs while the reactor is operating at 100-percent rated thermal power and has been at this power level for at least 100 days. B. Immediately before the postulated SBO event, the reactor and supporting systems are within normal operating ranges for pressure, temperature, and water level. All plant equipment is either normally operating or available from the standby state. C. It is assumed that a reasonable set of operator actions will occur to mitigate the effects of an SBO and recover from the event. Operator actions are assumed to follow plant operating procedures for the underlying symptoms or identified event scenario associated with an SBO. Operator actions to strip nonessential loads from batteries should not be credited to commence during the first 30 minutes of the SBO event. D. Actions specified in procedures for SBO are predicated on the use of instrumentation and controls powered by vital buses supplied by station batteries. E. The dc power needs for SBO may be estimated using the same methodology for which the plant is licensed; Institute for Electrical and Electronics Engineers (IEEE) Std 485 (Ref. 14) describes the generally