Document: NRC Regulatory Guide
Document ID: cfc61809-5745-460f-8a26-13c168659924
Document Type: regulatory_guide
Title: Identification and Characterization of Seismic Sources and Determination of Safe Shutdown Earthquake Ground Motion
Source: NRC Regulatory Guide Division 1
Source URL: https://www.nrc.gov/docs/ML0037/ML003740084.pdf
Revision Date: 2023-06
Chapter: 
Section ID: RG-1.165
CFR Part: 
CFR Title: 

Content:
uld be performed. 1.165-3 For existing nuclear power plant sites where addi tional units are planned, the geosciences technical in formation originally used to validate those sites may, be inadequate, depending on how much new or addi tional information has become available since the ini tial investigations and analyses were performed, the quality of the investigations performed at the time, and the complexity of the site and regional geology and seismology. This technical information should be utilized along with all other available information to plan and determine the scope of additional inves tigations. The investigations described in this regula tory guide are performed primarily to gather informa tion needed to confirm the suitability of the site and to gather data pertinent to the safe design and construc tion of the nuclear power plant. Appropriate geologi cal, seismological, and geophysical investigations are described in Appendix D to this guide. Geotech nical investigations are described in Regulatory Guide 1.132, "Site Investigations for Foundations of Nuclear Power Plants" (Ref. 8). Another important purpose for the site-specific investigations is to de termine whether there are new data or interpretations that are not adequately incorporated in the existing PSHA data bases. Appendix E describes a method for evaluating new information derived from the site specific investigations in the context of the PSHA. These investigations should be performed at four levels, with the degree of their detail based on distance from the site, the nature of the Quaternary tectonic regime, the geological complexity of the site and re gion, the existence of potential seismic sources, the po tential for surface deformations, etc. A more detailed discussion of the areas and levels of investigations and the bases for them is presented in Appendix D to this regulatory guide. The levels of investigation are char acterized as follows. 1. Regional geological and seismological