Document: NRC Regulatory Guide
Document ID: 688895c2-d1d9-44f3-9c79-3cf0daa88510
Document Type: regulatory_guide
Title: 
Source: NRC Regulatory Guide Division 4
Source URL: https://www.nrc.gov/docs/ML0037/ML003739541.pdf
Revision Date: 2023-06
Chapter: 
Section ID: RG-4.5
CFR Part: 
CFR Title: 

Content:
ng of the soil to considerable depths. B. Core Method Experience has shown that a total sample area of 460 to 930 cm2 (1/2 to I ft2) will provide d reasonably good estimate oftotal deposit if the area consists of a composite of ten or more individual plugs or cores, A tool for taking samples may be anything that takes a core or plug that is of equal area throughout its entire depth. A good pair of sampling tools is an 8.9-cm-diameter (3-1/2-in.-diameter) topsoil cutter that takes a 5-cm-deep (2-in.-deep) sample and a 8.3-cm-diameter (3-1[4-in.-diameter) barrel auger that cuts an 8.9-cm-diameter (3-1/2-in.-diameter) sample. The topsoil cutter is used to remove the sod to a depth of 5 cm, and the auger takes the remaining sample to the depth desired. The soil from ten cores sampled to a depth of 30 cm (12 in.) is composited to make a single sample weighing from 18 to 36 kg (40 to 80 pounds). If desired, the 0 to 5-cm sod samples may be kept separate, making a sample of higher concentration. The amount of contaminant found in the upper 5 cm and that found in the remaining subsurface are added to give the total for the 620 cm2 (0.67 ft 2) of surface represented by the ten cores. Powdery, dry, loose, single-grain soils cannot be sampled in a simple, satisfactory way by the core method. It is best to take sarpples when the soil contains enough moisture to be cohesive, even if this necessitates that, the area to be sampled be wetted by sprinkling. The procedure after the selection of an undisturbed site that meets the criteria previously discussed is as follows: Lay out a straight line transect about 4.6 m (15 ft) long. Since it may be desirable to resample the site at a later time, measure the coordinate distances to FrLed landmarks to identify the relative postion of the transect. Press the 5-cm-depth topsoil cuttei into the ground without twisting or disturbing the grass cover or surface soil. This may best be accomplished by stepping on the rim of the cutter with both