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:
S 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 Report 3002004396, “High Frequency Program: Application Guidance for Functional Confirmation and Fragility Evaluation,” if the GMRS from the reevaluated seismic hazard exceeds the design basis seismic hazard above 10 Hz. 6.1.2.2. Case 2: Demonstration of Reasonable Protection Based upon the Expedited Seismic Evaluation Process The EPRI report 3002000704, “Seismic Evaluation Guidance: Augmented Approach for the Resolution of Fukushima Near-Term Task Force Recommendation 2.1: Seismic,” (Ref. 38), described an expedited seismic evaluation process (ESEP) to evaluate the seismic ruggedness of SSCs for a review level ground motion (RLGM) derived by linearly scaling the design basis seismic hazard by the maximum ratio of it to the GMRS for the reevaluated seismic hazard in the 1 to 10 Hz range, with this ratio limited to a maximum of two times the design basis seismic hazard. Alternatively, licensees conducted the ESEP using the GMRS itself. The ESEP evaluated seismic adequacy of components in a single success path for core cooling, reactor coolant system makeup and containment capabilities for the RLGM or the GMRS resulting from the reevaluated seismic hazard. This process was endorsed by the NRC by letter dated May 7, 2013 (Ref. 39). Staff Position: The ESEP demonstrates reasonable protection of evaluated SSCs necessary for the maintenance or restoration of core cooling and containment capabilities for those licensees having reevaluated seismic hazards less than twice the design basis seismic hazard. 1. SSCs not within the scope of the ESEP should be evaluated for reasonable protection as follows: a. Qualitatively based on Seismic Experience. EPRI NP-6041-SL and EPRI TR- 104871, “Generic Seismic Technical Evaluations of Replacement Items for Nuclear Power