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:
viations are used in this RG ac alternating current ADAMS NRC Agencywide Documents Access and Management System AFW auxiliary feedwater AMS alternate mitigating strategy ASCE American Society of Civil Engineers BDBEE beyond-design-basis external event CFR U.S. Code of Federal Regulations DG draft regulatory guide EFW emergency feedwater ELAP extended loss of alternating current power EOP emergency operating procedure EPRI Electric Power Research Institute ESBWR economic simplified boiling-water reactor ESEP expedited seismic evaluation process DG-1301, Page 3 FLEX diverse and flexible coping strategies FR federal register FSAR final safety analysis report FSG FLEX support guidelines GL generic letter GMRS ground motion response spectrum HF high frequency HPCI high pressure core injection IAEA International Atomic Energy Agency IHS IPEEE high-confidence-of-low-probability-of-failure spectrum IPEEE individual plant examination of external events ISG interim staff guidance LLNL Lawrence Livermore National Laboratory LUHS loss of normal access to the ultimate heat sink NEA Nuclear Energy Agency NEI Nuclear Energy Institute NRC U.S. Nuclear Regulatory Commission NTTF Near-Term Task Force OECD Organization for Economic Co-operation and Development PGA peak ground acceleration RCIC reactor core isolation cooling RG regulatory guide RLE review level earthquake RLGM review level ground motion SAMGs severe accident management guidelines SEI Structural Engineering Institute SEL seismic equipment list SFP spent fuel pool SMA seismic margin assessment SPID screening, prioritization, and implementation details SRM staff requirement memorandum SPRA seismic probabilistic risk assessment SSC structure, system, and component THMS targeted hazard mitigating strategy B. DISCUSSION Reason for Issuance One of the primary lessons learned from the events at Fukushima Dai-ichi was the significance of the challenge presented by a loss of safety-related systems following the occurrence of a