Technical Updates on UTEVA Resin and TEVA Resin

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Technical Updates on UTEVA Resin and TEVA Resin
Denver May 2, 2002
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Topics

• UTEVA Resin
• Decontamination of Po-210
• U-232 yields
• TEVA Resin
• Decontamination of U-nat/Th in Tc-99 region

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U-232 Yields

• Unrealistic high U-232 yields reported with UTEVA
  resin in samples with high in Pb-210

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Current Procedure

• 1) Load sample on UTEVA resin with 10 ml of 3M
  HNO3/1M Al(NO3)3. with 2 mL of 0.6M Ferrous
  sulfamate and 200 mg of ascorbic acid.
• 2) Rinse sample beaker with 5 mL of 3M HNO3
• 3) Rinse column with 5 mL of 3M HNO3
• 4) Rinse column with 5 mL of 9M HCl
• 5) Rinse column with 20 mL of 5M HCl/0.05M Oxalic
• 6) Elute U with 15 mL of 0.01M HCl

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Effect of Ferrous210Pb/210Po spike (1100 pCi)
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Effect of Additional 3M HNO3 Rinse 210Pb/210Po
spike
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(No Transcript)
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Effect of Uranium Strip Solution no ferrous
added 210Pb/210Po spike (1100 pCi)
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Additional Rinse/1M HCl Strip Combo
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Revised Procedure

• 1) Load sample on UTEVA with 10 ml of 3M HNO3/1M
  Al(N03)3 with 2 mL of 0.6M Ferrous sulfamate and
  200 mg of ascorbic acid
• 2) Rinse sample beaker with 5 mL of 3M HNO3
• 3) Rinse column with 5 mL of 3M HNO3
• 4) Rinse column with 10 mL of 3M HNO3 (3x)
• 5) Rinse column with 5 mL of 9M HCl
• 6) Rinse column with 20 mL of 5M HCl/0.05M Oxalic
• 7) Elute U with 15 mL of 1M HCl

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Summary

• A good decontamination of Po-210 in U-232 region
  can be achieved by additional 3M HNO3 rinse on
  UTEVA and eluting uranium selectively with 1M HCl

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TEVA Column Tc-99 Issues

• Problem reported by Darrin Mann (BWXT, Oak Ridge,
  Tn) with bias high Tc-99 recoveries in samples
  with natural uranium.
• Th-234 interference was detected in Tc-99 region.

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BWXTs Tc-99 Procedure

• Solid samples are digested and dissolved finally
  in 20 ml of 0.1M HNO3
• Load sample on TEVA column
• Rinse column with 25 ml of 0.1M HNO3
• Extrude resin from the column in a LSC vial.
• Add cocktail and count on LSC.

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BWXTs Procedure tested at Eichrom

• Spiked 20 ml of 0.01M HNO3 with 2000 dpm of
  U-234/238
• Load on TEVA Resin column
• Rinse with 25 ml of 0.1M HNO3
• Extrude resin in LSC vial
• Added 15 ml of cocktail and count

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Possible Solutions for Decontamination

• Use of fluoride to complex the residual Th-234 on
  the column
• Two fluoride solutions tested
• Hydrofluoric acid
• Sodium fluoride

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Decontamination of Th-234

• Spiked 20 ml of 0.01HNO3 with 2000 dpm of
  U-234/238
• Load on TEVA Resin column
• Rinse with 5 ml of 0.1M HNO3
• Rinse with 25 ml of 0.5M HF/0.02M HNO3 OR with
  25 ml of 1M NaF/0.02 HNO3
• Rinse with 5 ml of 0.1 HNO3
• Extrude resin in LSC vial
• Added 15 ml of cocktail and count

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BWXTs ProcedureTest ResultsRinse volume
used25 mL
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Conclusion

• Decontamination of Th-234 in Tc-99 region can be
  accomplished with additional fluoride rinse on
  the TEVA Resin columns
• Fluoride in the form of 1M NaF or 0.5M HF
  solutions could be used to remove the residual
  amounts of Th-234