00J01587-01.ppt
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
00J01587-01.ppt
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
00J01587-01.ppt
Improvements In Column Extraction
• Upgraded process laboratory methods in 1996– Pu and Np by alpha spectrometry
– U by laser phosphorescence
– Pu and U actinide isotopics—TIMS
• 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)
00J01587-01.ppt
Improvements In Column Extraction
• Expanded to characterization of metals/oxides:– UTEVA method for Pu/U oxides (Impurity assay in mixed oxide or
actinide process solutions—1998-1999)
– Trace actinides in mixed oxide materials (Np, Th, Am extraction for ICP-MS using TEVA, UTEVA—1998-1999)
– 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
00J01587-01.ppt
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 Pu+3: ferrous sulfamate + ascorbic acid
– 3M HNO3 rinse
– Pu +3 / U +6 not retained on TEVA
– Strip Np+Th together using 5 mL 0.02M HNO3-0.005M HF
• Use 2nd TEVA column to remove nearly all U+Pu
• 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
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
Element % Recovery Element % Recovery Element % Recovery
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Average Column Spike RecoveriesICP-MS
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
Element % Recovery Element % Recovery Element % Recovery
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Analysis of CRM-124 Uranium Oxide Standards
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
Measured Ref. Prepared Value/Element (ppm) dc arc range (ppm) %Difference
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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
