Th, Pu

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Th, Pu U Separation Using TEVA and UTEVA Resin
Eichrom Workshop at RRMC 12 November,
2002 Knoxville, TN
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Objective
To develop a quick method for the separation of
Th, Pu and U in water samples
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Tracers

• U232 tracer cleanup required to remove daughter
  Th228
• Followed David Sill (NAREL)s BaSO4 procedure
• Pu242 and Th229 used for plutonium and thorium
• Pu236 better choice if Np measurement is required

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Sample Preparation

• 1 liter aliquots of acidified water samples were
  spiked with Th229, Pu242 and U232 tracers
• Samples were heated to near boiling for 2 hours
• A Ca3(PO4)2 precipitation was performed
• Decant supernatant, centrifuge and collect the
  precipitate

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Load Solution

• Dissolve precipitate in 3M HNO3/1M Al(NO3)3
  solution
• Add ferrous sulfamate and NaNO2
• Load on TEVA and UTEVA Resin cartridge in tandem

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Proposed Procedure

• 1) Attach TEVA resin and UTEVA resin cartridges
  in tandem
• 2) Load 10 ml of 3M HNO3/1M Al(N03)3. with 2 mL
  of 0.6M Ferrous sulfamate followed with 1 ml of
  3M NaNO2
• 3) Rinse sample beaker with 5 mL of 3M HNO3
• 4) Rinse cartridge with 5 mL of 3M HNO3
• 5) Separate TEVA and UTEVA cartridges

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Proposed Procedure continued

• TEVA cartridge
• 1) Rinse with 30 ml of 3M HNO3
• 2) Elute Th with 20 ml of 9M HCl and 5 ml of 6M
  HCl
• 3) Elute Pu with 20 ml of 0.02M TiCl3/0.05M
  HCl/0.05M HF (Np eluted in this fraction)

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Proposed Procedure continued

• UTEVA Cartridge
• 1) Rinse with 5 ml of 9M HCl
• 2) Elute U with 15 ml of 1M HCl

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Direct Spike Results(Proposed Procedure)
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U fraction contaminated with Pu
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Improvements Needed

• Possible Pu valence adjustment for better
  recoveries
• U recoveries need to be higher
• Better decontamination for U fraction

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Possible Solutions for Improvements

• 1) Use 2 ml of ferrous sulfamate 0.5 ml of
  NaNO2
• 2) Use 1 ml of ferrous sulfamate 1 ml of NaNO2
• 3) Increase U and Pu strip volumes
• 4) Add oxalic acid rinse on UTEVA

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Direct Spike Results(2 ml of Ferrous0.5ml of
NaNO2 )
With 25 ml of Pu strip volume
With 20 ml of U strip volume oxalic acid rinse
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Direct Spike Results(1 ml of Ferrous 1ml of
NaNO2)
With 25 ml of Pu strip volume
With 20 ml of U strip volume oxalic acid rinse
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Revised Procedure

• 1) Load sample on TEVA resin and UTEVA resin
  cartridges in tandem with 10 ml of 3M HNO3/1M
  Al(N03)3. with 1.0 mL of 0.6M ferrous sulfamate
  and 1 ml of 3M NaNO2
• 2) Rinse sample beaker with 5 mL of 3M HNO3
• 3) Rinse cartridge with 5 mL of 3M HNO3
• 4) Separate TEVA and UTEVA cartridges

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ACW13 continued

• TEVA cartridge
• 1) Rinse with 5 ml of 3M HNO3
• 2) Rinse with 30 ml of 3M HNO3
• 3) Elute Th with 20 ml of 9M HCl and 5 ml of 6M
  HCl
• 4) Elute Pu with 25 ml of 0.02M TiCl3/0.05M
  HCl/0.05M HF (Np will be present in this
  fraction)

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Revised ACW13 continued

• UTEVA Cartridge
• 1) Rinse with 5 ml of 3M HNO3
• 2) Rinse with 5 ml of 9M HCl
• 3) Rinse with 20 ml of 5M HCl/0.05M oxalic acid
• 4) Elute U with 20 ml of 1M HCl

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Decontamination Test

• 100 pCi of Am, Np, Th, Pu and U were added to
  the load solution
• Solution was processed following ACW13

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Decontamination Factors
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DI Water
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Th229 Spectrum
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U232 Spectrum
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Pu242 Spectrum
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Tap Water
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Summary

• Benefits
• A quick method with consistent, reproducible
  recoveries
• Rugged enough to provide good decontamination
  from other actinides
• Drawbacks
• Th228 cleanup required
• Pu236 tracer required if Np237 measured