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:
is guide is acceptable when it can be shown that the alternative techniques yield satisfactory results. 4.2 Surface Investigations Detailed surface geologic and geotechnical engineering investigations should be conducted over the site area to assess all pertinent soil and rock characteristics. The definition of site area, as specified in RG 1.208, is that area within a radius of 8 kilometers (5 miles) of the site. Appendix A to this guide lists some of the special geologic features and conditions to be considered. The initial step in conducting detailed surface investigations for a site is to prepare three-dimensional topographic maps at a scale suitable for plotting the geologic features and characteristics and showing features in the surrounding area that are related, for example, to borrow areas, quarries, and access roads. Aerial photographs and stereoscopic image pairs, other remote sensing imagery (e.g., satellite imagery and LiDAR), and the results of geophysical surveys are valuable for regional analysis, determination of fault and fracture patterns, location of potential nontectonic surficial features related to possible subsurface dissolution, and other features of interest. Depending on the site, detailed mapping of the following site characteristics and associated features should be considered during conduct of the surface investigations: • topography (including geomorphic features, lineaments, paleo-landslides, closed depressions, river terraces, and alluvial and glacial deposits), • hydrology (including rivers, streams, lakes, wetlands, local drainage channels, springs, and sinkholes), DG-1392, Page 13 • geology (including outcrops; tectonic features such as faults, shear zones, and zones exhibiting strong fracturing or alteration; nontectonic features 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