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:
. Digest with some stirring for about an hour. 4. Remove from the hotplate and cool. Carefully add 20 ml of HCI (38%) and stir. Heat on a hotplate for 45 minutes with occasional stirring. 5. Add about 5 g of powdered boric acid, and digest for an additional 1. min. Stir occasionally. 6. Add about 200 ing of sodium bisulfite and digest on a hotplate. Continue heating and evaporate to a liquid volume of-10 ml. 7. Add -50 ml of water and digest on a hotplate with stirring for -10 min to dissolve soluble salts. 8. Cool. Using a wash bottle, transfer approximately equal parts of the total sample into two 220-mI centrifuge bottles. (Note 4) 9. Add I ml of iron carrier solution (10 mg Fe/ml) to each centrifuge bottle and stir. 10. Add NaOH (50% solution) with stirring to each bottle to a pH of -9. Add 5-10 ml excess of NaOH and stir for I min. I1. Centrifuge for -5 min, decant, and discard the supernate. 12. Dissolve the precipitate with about 30 ml of 8N HNO3 saturated with boric acid. Digest in a hot water bath for 10 min. 13. Cool and centrifuge for -5 mrin. Decant the supernate into the original 250 ml PTFE beaker and save. 4.5-7 4. Wash the residue with 8N HNO3 saturated with boric acid, centrifuge for S min. and combine supernates. Discard the residue. S. Heat the supernate on a hotplate and evaporate to near drynes. 6. Add -30 ml of water and heat to disolve the salts. Cool, and tramfer equal portions into centrifuge tubes. 17. Add NH4FOH, dropwise with stirring, to a pH of -9. 18. Centrifuge and discard the supemate. 19. Dissolve the precipitate with a minimum of concentrated !1N 3 O (70%) and transfer using 8N HNO3 solution into a 250-ml beaker. Add 8N HNOs to a vowume of approximately 75 ml. (Note 5) 20. Add -200 mg of sodium nitrite (NaNO 2 ) crystals and stu with a stirring rod, bring to a quick gentle boil on a hotplate, and cool. Avoid prolonged heating. 21. Passr through an anion-exchange resin column previously pretrested with SN WO3. WsA with six column