Document: NRC Regulatory Guide
Document ID: 8e45dce1-e1e7-4415-b1dd-7e2a610e545b
Document Type: regulatory_guide
Title: Fire Protection for Nuclear Power Plants (Rev. 4)
Source: NRC Regulatory Guide Division 1
Source URL: https://www.nrc.gov/docs/ML2023/ML20231A835.pdf
Revision Date: 2023-06
Chapter: 
Section ID: RG-1.189
CFR Part: 
CFR Title: 

Content:
amples of components that should be considered part of the safe-shutdown success path and components that are important to safe shutdown are listed below. Appendix H to NEI 00-01, Revision 4, provides additional information about the classification of safe-shutdown equipment when applied in conjunction with this guide. Examples of Safe-Shutdown Success Path SSCs • reactivity control SSCs that are required to achieve and maintain cold-shutdown reactivity conditions • reactor coolant makeup SSCs that are required to maintain the reactor coolant level above the top of the core for BWRs and within the level indication in the pressurizer for PWRs • reactor heat removal SSCs that are required to achieve and maintain decay heat removal • process monitoring SSCs that are required to provide direct readings of the process variables necessary to achieve and maintain safe shutdown • supporting SSCs that are required to provide the process cooling, lubrication, and other functions necessary to permit the operation of the equipment used to achieve and maintain safe shutdown • significant diversion paths from flowpath that would lead to core damage or cause reactor coolant loss if diverted for 1 hour or less DG-1359, Page 82 • power supplies for safe-shutdown success path components Examples of SSCs Important to Safe Shutdown • success path supply tank spurious drain or bypass • decay heat removal system valves, when not part of safe-shutdown success path • HVAC systems and components required to provide cooling to success path components to the extent that cooling is required for post-fire safe shutdown • power-operated relief valves and safety relief valves not part of safe-shutdown success path • spurious start of equipment not relied on for a safe-shutdown success path, which could cause overfill conditions • small diversion paths from success path flowpath (smaller than the significant diversion paths described above) • multiple separate small