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:
el. Cool to room temperature before carefully adding HF. 4. If large centrifuge tubes are not available, it might be expeditious to perform the precipitation in a beaker fkti, to allow the precipitate to settle somewhat, to decant the supernate, and then to complete the separation by aentriftsion. 5. If the volume of the hydroxide precipitate i, considerably greater than should be expected from the 10 mg of Fe added, the final volume should be brought up to -100 nd with 8N HNOI or. alternatively, the dissolved hydroxides ahould be evaporated to salts first before addition of the 8N HNO3 solution. The final normality of the HNO0 solution is not extremely critical, but should be ip the range of 7-9. 6. In the absence of an excessive amount of salts (And this should be the case with l0g soil samples), a resin column with dimensions of approximately 1.3 cm ID by 10 cm of wet. settled resin should be adequate. E. Ekletrmdeposition 1. Add 1-1/2 to 2 ml of 4N HCI into the beaker and. wuing a "disposable pipette" (2-m gltass eye-dropper type, with 2-ml bulb), rise down the sides of the beaker with the sample solution. Transfer the solution into a plating cell. 2. Add another 1-1/2 to 2 ml of 4N .C1 solution into the beaker, rinse as above, and add to the plating call. 3. Repeat the above step with -I ml of H2 0. 4. Add a drop of thymol blue indicator solution uiid add concentrated NH4OH dropwise until the color changes to yellow. 5. Add 2N HCI solution dropwise to a salmon-pink end point. 6. Electroplate at 1.5 A for 20 min. 4.5-N 7. At the end of 20 min, add 2.3 ml of coomtrated NIl 4 OH (two shots with 2.rd disposable pipette). and leave the current on for another 20 sec. 24. Turn the current off, rinse out the solution into a beaker with H20, and dismantle the cell, Rinme the disc with H20, and dry it on a hotplate at medium heat for 5 min. The sample is ready for counting. F. Counting A properly electrodeposited sample should be free of residue. Normally, three