Document: NRC Regulatory Guide
Document ID: 921f4c90-482e-4f9e-a835-28839c357dcb
Document Type: regulatory_guide
Title: Flexible Mitigation Strategies for Beyond-Design-Basis Events + HISTORY - HISTORY 11/2015 – DG-1301 , Proposed Revision 0
Source: NRC Regulatory Guide Division 1
Source URL: https://www.nrc.gov/docs/ML1316/ML13168A031.pdf
Revision Date: 2023-06
Chapter: 
Section ID: RG-1.226
CFR Part: 
CFR Title: 

Content:
iance with the § 50.155(b)(1) condition of loss of all ac power is not limited to seismically-induced events; it is a necessary element of compliance for that requirement regardless of the initiating event. Because NEI 12-06, Rev. 1A, Section 5 is applicable to all power reactor licensees, conformance to NEI 12-06, Rev. 1A, Section 5.3.3 can provide the capabilities necessary to meet that element regardless of the initiating event. 2. Equipment Capacity and Capability 10 CFR 50.155(c)(1) requires that the equipment relied upon for the mitigation strategies required by § 50.155(b)(1) have sufficient capacity and capability to simultaneously maintain or restore DG-1301, Page 11 core cooling, containment, and SFP cooling capabilities for all the power reactor units within the site boundary. NEI 12-06, Rev. 1A, Section 3.2.2, Guideline (16), provides guidance for the minimum number of sets of equipment a licensee should provide in order to achieve reasonable assurance that the equipment will be available in sufficient quantity to have the capacity and capability necessary to comply with § 50.155(c)(1). This includes guidance for the provision of spare hoses and cables in a quantity that is either (1) equivalent to 10% of the total length of each type of hose or cable necessary; or (2) of sufficient length and sizing to replace the single longest run needed to support any single strategy. NEI 12-06, Rev. 1A, Sections 11.1 and 11.2 provide guidance on the quality attributes and equipment design a licensee may use to achieve reasonable assurance that the individual pieces of equipment have the capability to perform the functions they are intended for in the FLEX strategies. Staff Position: NEI 12-06, Rev. 1A, Section 3.2.2, Guideline (16) and Sections 11.1-2, provide an acceptable method to demonstrate compliance with § 50.155(c)(1). 3. Reasonable Protection 10 CFR 50.155(c)(2) requires that the equipment relied upon for the mitigation strategies required by §