Document: NRC Regulatory Guide
Document ID: db0cf2ba-a5df-49f8-9003-005c7f8bd08a
Document Type: regulatory_guide
Title: Combining Modal Responses and Spatial Components in Seismic Response Analysis (Rev. 3)
Source: NRC Regulatory Guide Division 1
Source URL: https://www.nrc.gov/docs/ML1814/ML18142B201.pdf
Revision Date: 2023-06
Chapter: 
Section ID: RG-1.92
CFR Part: 
CFR Title: 

Content:
t insights from this benchmark will inform the need to update certain aspects of the regulatory positions in RG 1.92. 2. What is the impact on internal and external stakeholders of not updating the RG for the known issues, in terms of anticipated numbers of licensing and inspection activities over the next several years? RG 1.92 is used when a licensing activity involves a seismic response analysis of an SSC that requires the combination of modal responses or spatial components. It applies to any new application or review of plant modifications requiring a RSA. However, this RG is considered mostly applicable in new reactor applications. Since none is anticipated in the next several years (2 to 5 years), updating this RG is not critical at this time. For small modular reactors the NuScale design certification is almost complete and the existing guidance was deemed acceptable for a design certification. 3. What is an estimate of the level of effort needed to address identified issues in terms of full-time equivalent (FTE) and contractor resources? NRC staff requires approximately 2.5 FTEs to complete the proposed rigorous benchmarks of the RSA methods and the 100-40-40 rule, and identification or development of approaches to consider HRHF response spectra, as described above inIssues (A) through (C). This level of effort also includes documenting the results in a report, developing the revised RG, and discussing the analytical results and any resultant changes/additions to the regulatory guidance with staff in the NRC program offices. Based on the results of these activities, contractor support may be required for a consensus review by an external expert panel. 4. Based on the answers to the questions above, what is the staff action for this guide (Reviewed with no issues identified, Reviewed with issues identified for future consideration, Revise, or Withdraw)? Reviewed with issues identified for future consideration. 5. Provide a conceptual plan and timeframe to