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:
in the Central and Eastern US: Resolution of the Charleston Earthquake Issue” (Ref. 35). c. In some cases, past SPRAs were submitted for IPEEE closure that used input motions and hazard curves that preceded the LLNL and EPRI hazard curves of NUREG-1488 and EPRI NP-6395-D respectively. Consistent with the input spectrum shape used in an IPEEE, a licensee can develop an IPEEE high-confidence-of-low-probability-of-failure spectrum (IHS). Staff Position: The evaluation of redundant safe shutdown success paths under the IPEEE demonstrates the reasonable protection of equipment necessary to maintain or restore core cooling and containment capabilities for licensees provided that: a. The IHS envelopes the GMRS for the reevaluated seismic hazard from 1 to 10 Hz, with the exception of small narrowband exceedances that meet the criteria of the EPRI 1025287, “Seismic Evaluation Guidance: Screening, Prioritization and Implementation Details (SPID) for the Resolution of Fukushima Near-Term Task Force Recommendation 2.1: Seismic” (Ref. 36); and b. The previous seismic evaluation was accepted by the NRC in the letter dated May 9, 2014, (Ref. 37), or is subsequently accepted by the NRC to screen out of conducting a seismic risk evaluation based on the IHS; and DG-1301, Page 17 c. If the licensee performed an EPRI SMA, a plant-specific evaluation shows that SSCs that limit the coping duration to 72 hours are available for an indefinite period to support continued maintenance of the safe shutdown conditions. Licensees relying on the IHS to demonstrate reasonable protection of equipment necessary to maintain or restore core cooling and containment capabilities should: a. Evaluate the seismic capacity of equipment necessary to maintain or restore SFP cooling capabilities to the GMRS for the reevaluated seismic hazard; and b. Evaluate HF sensitive in-plant SSCs relied upon to maintain or restore core cooling, containment and SFP cooling capabilities using the methods of the EPRI