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:
-1392, Appendix D, Page D-2 APPENDIX D, Cont’d. STRUCTURE SPACING OF BORINGS2 OR SOUNDINGS MINIMUM DEPTH OF PENETRATION Buildings, retaining walls, concrete dams Principal borings: one boring at the center of safety-related structures and additional borings along the periphery, at corners, and other selected locations. For larger, heavier structures, such as the containment and auxiliary buildings, at least one boring per 900 m2 (10,000 ft2) (approximately 30 m (100 ft) spacing). One boring per 30 m (100 ft) for essentially linear structures. At least one-fourth of the principal borings and a minimum of one boring per structure to penetrate into sound rock or to a depth equal to dmax. Others to a depth below foundation elevation equal to the width of structure or to a depth equal to the width of the structure or to a depth equal to the foundation depth below the original ground surface, whichever is greater.3 Earth dams, dikes, levees, embankments Principal borings: one per 30 m (100 ft) along axis of structure and at critical locations perpendicular to the axis to establish geological sections with ground water conditions for analysis.2 Principal borings: one per 60 m (200 ft) to dmax. Others should penetrate all strata whose properties would affect the performance of the foundation. For water-impounding structures, to sufficient depth to define all aquifers and zones of underseepage that could affect the performance of structures.2 Deep cuts,4 canals Principal borings: one per 60 m (200 ft) along the alignment and at critical locations perpendicular to the alignment to establish geologic sections with ground water conditions for analysis.2 Principal borings: one per 60 m (200 ft) to penetrate into sound rock or to dmax. Others to a depth below the bottom elevation of excavation equal to the depth of cut or to below the lowest potential failure zone of the slope.2 Borings should penetrate pervious strata below which ground water may influence stability.2