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:
on sampler Hole is advanced and reamed by core drill while sample is retained in nonrotating inner core barrel with core catcher. Cuttings removed by circulating drilling fluid. Undisturbed samples in stiff-to-hard cohesive soil, sand with cementation, and soft rocks. Disturbed sample may be obtained in cohesionless materials with variable success. Not suitable for undisturbed sampling in loose, cohesionless soils or soft, cohesive soils. Difficulties may be experienced in sampling alternating hard and soft layers. Shot core boring (Calyx) Boring is advanced by rotating single core barrel, which cuts by grinding with chilled steel shot fed with circulating wash water. Used shot and coarser cuttings are deposited in an annular cup, or calyx, above the core barrel. Large-diameter cores and accessible boreholes in rock. Cannot be used in drilling at large angles to the vertical. Often ineffective in securing small diameter cores. Oriented integral sampling Reinforcing rod is grouted into small diameter hole, then overcored to obtain an annular core sample. Core samples in rock with preservation of joints and other zones of weakness. Samples are not well suited to tests of physical properties. Wash sampling or cuttings sampling Cuttings are recovered from wash water or drilling fluid. Samples useful in conjunction with other data for identification of major strata. Sample quality is not adequate for site investigations for nuclear facilities. Submersible vibratory (Vibracore) sampler Core tube is driven into soil by vibrator. Continuous representative samples in unconsolidated marine sediments. Because of high area ratio and effects of vibration, samples may be disturbed. Underwater piston corer Core tube attached to drop weight is driven into soil by gravity after a free fall of controlled height. Representative samples in unconsolidated marine sediments. Samples may be seriously disturbed. Cable-supported piston remains in contact with soil surface during drive.