Document: NRC Regulatory Guide
Document ID: a094549d-8685-4dad-b90f-c28c7d279a53
Document Type: regulatory_guide
Title: Geologic and Geotechnical Site Characterization Investigations for Nuclear Power Plants + HISTORY – HISTORY 08/2021 – DG-1392 , Proposed Revision 3 07/2014 – Periodic Review of Revision 2 – Reviewed with no issues identified 02/2001 – DG-1101 , Proposed Revision 2 (Rev. 3)
Source: NRC Regulatory Guide Division 1
Source URL: https://www.nrc.gov/docs/ML2119/ML21194A176.pdf
Revision Date: 2023-05
Chapter: 
Section ID: RG-1.132
CFR Part: 
CFR Title: 

Content:
eatures such as surficial indicators of subsurface dissolution; rock unit contacts), and • engineering geology (including soil conditions and soil types, chemically or physically weathered zones and horizons, and areas exhibiting material properties conducive to soil liquefaction). All maps produced should include standard map labels such as scales, a north arrow, map projection information, title, and citation of original data or data sources. 4.3 Subsurface Investigations Subsurface investigations expand knowledge of the three-dimensional distribution of geologic features and characteristics and geotechnical engineering properties at the site and in borrow areas. Subsurface investigations also provide information on potential natural hazards such as nontectonic underground features (e.g., dissolution cavities), hidden faults, soft zones, or geologic contacts. The investigations should use a variety of appropriate methods, including borings and excavations augmented by geophysical measurements and geophysical surveys. Appendix C to this guide tabulates methods of conducting subsurface investigations. Techniques employing different measurement approaches should be used to determine geologic conditions and geotechnical engineering properties to account for uncertainties in the data and to cross-check the conformability and reasonableness of the data obtained during site investigations. An adequate number of tests for each method should be performed to quantify the mean and variability of pertinent site parameters and geotechnical engineering properties of subsurface materials. Locations and depths of borings, excavations, and geophysical measurements should be selected such that site-specific geology and foundation support conditions are sufficiently defined in both lateral extent and depth to permit the suitable design of all necessary excavations and engineered structures. The information acquired should also support development of geologic cross sections and