Document: NRC Regulatory Guide
Document ID: bbd6ed7f-058c-4bd2-8849-f708d0179bbf
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:
and SSCs within the scope of the demonstration considering all pertinent failure modes (both the individual and system level failure modes) that could prevent the functional performance needed for the mitigating strategies as discussed in provisions c through k below. This should include consideration of seismic interactions, evaluation of soil related failure modes, and consequential failures. c. Licensees should evaluate structures containing cooling and makeup water, fuel, and equipment relied on for the mitigating strategies under NEI 12-06, Rev. 1A, Sections 3.2.1.3.3 through 3.2.1.3.7, 3.2.2.5, and footnote 4 to Section 3.2.3 for robustness as defined in NEI 12-06, Rev. 1A, Appendix A using the reevaluated seismic hazard rather than the design basis seismic hazard. Deformation of the structures is acceptable so long as they will remain functional (i.e., retain the fluids and allow access for deployment and use of the equipment as well as support equipment functionality). d. Licensees should evaluate delivery systems for cooling and makeup water and fuel relied on for the mitigating strategies under NEI 12-06, Rev. 1A, Sections 3.2.1.3.4, 3.2.1.3.10, 3.2.2.5 and 3.2.2.13 for robustness as defined in NEI 12-06, Rev. 1A, Appendix A using the reevaluated seismic hazard rather than the design basis seismic hazard. Deformation of the systems is acceptable so long as they will remain functional (i.e., retain the fluids and allow their flow). e. Licensees should evaluate portable equipment and the means to move that equipment that is stored as described in NEI 12-06, Rev. 1A, Section 5.3.1.1.a to confirm that securing and protection from seismic interactions at the new seismic hazard level remains acceptable. The structure housing the equipment should be evaluated to confirm it has adequate seismic margin to protect the equipment at the reevaluated seismic hazard. f. Licensees should evaluate portable equipment and the means to move that equipment that is stored as