Rapid Extraction Methods for the Process Laboratory

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Rapid Extraction Methods for the Process
Laboratory

• S. L. Maxwell, III
• V. D. Jones
• S. T. Nichols
• J. Satkowski
• M. A. Bernard
• Westinghouse Savannah River Site

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Improvements In Column Extraction

• 1990s Need to upgrade radiochemistry methods at
  SRS
• Methods developed and implemented
• Rapid Column Extraction Applications at SRS
• Pu, Np, U, Am, Th, Sr, Tc-99 for waste and
  process solutions at SRS (tandem methods)
• E. Philip Horwitz, S.L. Maxwell et al., Analytica
  Chimica Acta, 310, 63, (1995).
• TEVA UTEVA TRU sequential methods
• Applied primarily to waste tank samples

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Improvements In Column Extraction

• Upgraded process laboratory methods in 1996
• Pu and Np by alpha spectrometry
• U by laser phosphorescence
• Pu and U actinide isotopicsTIMS
• S.L. Maxwell III, Rapid Actinide-Separation
  Methods, Radioactivity and Radiochemistry, 8, No
  4, 36, (1997)
• Pu-TEVA (valence-ferrous sulfate/sodium nitrite)
• Np-TEVA (valence-ferrous sulfamate ascorbic
  acid)
• U on UTEVA (valence-ferrous sulfamate)
• Dual column TEVA UTEVA cartridge
  (valence-ferrous sulfate/sodium nitrite)

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Improvements In Column Extraction

• Expanded to characterization of metals/oxides
• UTEVA method for Pu/U oxides (Impurity assay in
  mixed oxide or actinide process
  solutions1998-1999)
• Trace actinides in mixed oxide materials (Np, Th,
  Am extraction for ICP-MS using TEVA,
  UTEVA1998-1999)
• New UTEVA method for Pu and U-Isotope Dilution
  Mass spectrometry in mixed oxides (strip Pu
  separately using 3M HNO3-0.2MHF) -(2000)

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UTEVA Pu/U Separation for IDMS Assay by TIMS

• Currently Pu isotopics on TEVA U on UTEVA
• For mixed U/Pu solutions requiring
  assay/isotopics, combine on UTEVA
• Approach
• Load on UTEVA
• Strip Pu first using 3M HNO3-0.2M HF, then strip
  U with 0.02M HNO3-0.005M HF.
• Reduces labor costs and improves productivity

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UTEVA Pu/U Separation for IDMS Assay by TIMS

• 1 mL UTEVA resin
• U-233 (140 ug) and Pu-244 (0.7 ug) spiked samples
• Load solution 5 mL 2.5 M HNO3-0.5M Al (NO3) 3
• Valence adjustment to Pu (IV) with ferrous
  sulfate/nitrite
• Column rinse 13 mL 3M HNO3
• Pu strip 5 mls 3M HNO3 -0.2M HF (ash well to
  remove F)
• U strip 5 mL 0.02M HNO3 -0.005M HF

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Np, Th in Mixed Oxide by ICP-MS

• Material dissolution by microwave
• Dilution in glove box separation in radiohood
• Np and Th on 1 mL TEVA resin
• Load solution 2.5M HNO3-0.5M Al(NO3) 3
• Reduce Pu to Pu3 ferrous sulfamate ascorbic
  acid
• 3M HNO3 rinse
• Pu 3 / U 6 not retained on TEVA
• Strip NpTh together using 5 mL 0.02M HNO3-0.005M
  HF
• Use 2nd TEVA column to remove nearly all UPu
• Dilute and analyze by ICP-MS
• 95 recovery

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UTEVA Pu/U Removal for Metals Assay

• Background
• AG MP-1 Anion resin for Pu removal prior to
  ICP-AES/MS of impurities in metal/oxides to
  removal spectral interference
• Problem at least partial retention of Au, Ag,
  Pt, Ir, Pd, Nb, Tl, La, Ce and Ta on anion resin
• Increased need to analyze mixed Pu/U materials
  requiring Pu/U removal
• UTEVA resin offers improved impurity recovery and
  removes both Pu and U

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UTEVA Pu/U Removal Method

• UTEVA resin (diamylamylphosphonate)
• Recovers all impurities except Au
• Zr, Ta, Hf, Nb require dilute HF in column load
  (and/or rinse) solution
• Handles Pu, U or Pu/U mixtures
• Large 10 mL columns remove 200 mg or more of Pu/U
• Au done by dilute HCL-HF cation method

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UTEVA Pu/U Removal Method for Impurities Assay

• Glove box separation for Pu materials
• Load solution 10 mL 8 M HNO3-0.04M HF
• Column rinse 14-19 mLs 8M HNO3 (optional with
  HF)
• Adjust to 25 or 30 mL in graduated tube
• Pu/U recovery from resin 20 mL 0.1M HCl-0.05M HF
• Note
• No HF in rinse to enhance Pu retention still
  adequate recovery of Zr, Ta, Hf, Nb
• May increase HF with U only to increase Ta, etc.,
  but minimize to minimize Si background at
  ICP-torch due to HF
• Load solution can be larger
• HF in rinse may be necessary if HF is less in
  load solution

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Average Column Spike RecoveriesICP-AES
Element Recovery Element Recovery Element
Recovery

• Ag 92 Hf 84 Se 101
• Al 99 Hg 69 Si 151
• As 90 K 87 Ta 69
• B 100 La 100 V 98
• Ba 100 Li 97 W 106
• Be 98 Mg 105 Zn 101
• Ca 94 Mo 98 Zr 63
• Cd 96 Na 105
• Ce 103 Nb 99
• Cr 102 Ni 101
• Cu 98 P 161
• Fe 106 Pb 84
• Ga 104 S 97

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Average Column Spike RecoveriesICP-MS
Element Recovery Element Recovery Element
Recovery

• Ag 106 Hf 90 Se 87
• Al 101 Hg 77 Si 132
• As 88 K 102 Ta 84
• B 89 La 108 V 104
• Ba 106 Li 101 W 113
• Be 90 Mg 103 Zn 91
• Ca NA Mo 101 Zr 63
• Cd 94 Na 98
• Ce 108 Nb 98
• Cr 103 Ni 103
• Cu 106 P 154
• Fe 106 Pb 99
• Ga 101 S NA

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Analysis of CRM-124 Uranium Oxide Standards
Measured Ref. Prepared Value/ Element (ppm)
dc arc range (ppm) Difference

• Al 102 105 (81-120) -3
• Be 11.6 12.5 (10-17) -7
• Cr 55.4 52 (50-64) 6
• Mg 52.4 51 (37-86) 3
• Mo 53.7 50 (30-50) 7
• Na 230 200 (189-252) 15
• Ni 106 102 (92-158) 4
• V 24.2 25 (23-30) -3
• W 105 100 (86-95) 5
• Zn 110 102 (75-115) 8
• Zr 108 100 (67-100) 8
• measured single solution analyzed once by
  ICP-AES and ICP-MS

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Am in Mixed Oxide by ICP-MS

• Use solution (8M HNO3) from initial UTEVA resin
  separation (10 ml resin) for metal impurities
• No retention of Am on UTEVA resin
• Remove traces of uranium and plutonium using 2 ml
  UTEVA column
• 2 mL aliquot
• 8 mL 8M HNO3 column rinse
• Dilute to low acid
• Analyze by ICP-MS

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Summary

• Process column methods
• Faster and more rugged
• Reduced labor costs
• Better accuracy and precision
• Reduced rework
• No mixed waste solvents