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:
60 cm wide by 90 cm long by 60 cm deep immediately, adjacent to the clipped area, placing the removed dirt on the tarpaulin. Usually, the sod can be cut out in blocks, making it easy to replace after sampling. Smooth the long side of the trench adjacent to the clipped area with a flat blade shovel or mortar trowel, making it perpendicular to the surface. Take the first 5-cm increment by pushing a three-sided square pan with cutting edges on the open side (' 5 cm x 15 cm x 5 cm deep) into the side 5 cm below the ground surface. Use a sharp flat-bladed knife to score the edges. then 4.5-3 rcrnmve the first cut and seal in a small plastic bag. Cut away the topsoil on either side of the first cut to make a ,he.-f about 45 cm long by 15 cm wide and 5 cm from the ,irface. Lightly brush away any particles that may have faLlen on the shelf. Apin, push the open-end cutting pan into the side, cut, and remove the next 5-cm-thick incremental sample. Continue this procedure until samples have been taken to the desired depth. The actual depth of a cut can be determined between cuts by placing a two by four on the surface and measuring the distance from the lower surface of the two by four to the subsurface. When all of the samples have been taken, fill the trench with dirt from the tarpaulin, and replace the sod taken from the trench. A depth profile is useful only for finding the relative vertical distribution of the radionuclide. Therefore, it is necessary to sample deeply enough that close to 100 percent of the radionuclide is measured. Since only 230 cm2 of surface area at one spot is umpled when depth increments are taken, the integrated deposit is not necessarily representative of the area. 2. Equipment Three-sided square pan with cutting edges on. open side (15 cm x 15 cmx 5 cm deep made of 0.16-cm-thick cold-rolled steel, welded at the comers). Plastic bags, 52 x 23 x 0.02 cm (20i x 9 x o0o00 in.) Mortar trowel Long flat-bladed knife Meter stick (or 24-in. ruler) One 1.5