Document: NUREG-0800
Document ID: 33d57664-26a3-4d30-807d-2ce020de062a
Document Type: srp
Title: STATION BLACKOUT
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML1007/ML100740424.pdf
Revision Date: 2023-06
Chapter: 8
Section ID: 8.4
CFR Part: 
CFR Title: 

Content:
derlying 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 accepted methodology. For passive plant designs (e.g., AP1000), where steady-state loads should operate for up to 72 hours under SBO conditions, the staff considers the steady-state 8.4-11 Revision 1- May 2010 loading condition to be the governing factor for determining the Class 1E battery size (Refs. 28 and 34). F. Since the capacity of battery storage varies with electrolyte temperature, calculations should assume the lowest temperature normally expected of the battery. G. The capability of all systems and components necessary to provide core cooling and decay heat removal following an SBO should be determined, including station battery capacity, condensate storage tank (CST) capacity, compressed air capacity, and instrumentation and control needs. The non-safety systems identified in Appendix A to RG 1.155 are acceptable to the NRC staff for responding to an SBO. H. The ability to maintain adequate reactor coolant system inventory to ensure that the core is cooled should be evaluated, taking into consideration shrinkage, leakage from pump seals, and inventory loss from letdown or other normally open lines dependent on ac power for isolation. I. The design adequacy and capability of equipment needed to cope with an SBO for the required duration and recovery period should be addressed and evaluated as appropriate for the associated environmental conditions. This should include consideration of the