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Published byJunior Scott Modified over 9 years ago
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New Applications of Rapid Column Extraction for Methods at SRS Sherrod L. Maxwell III Savannah River Site
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Recent Developments/Applications Current Actinide Methods –Pu/Np/U/Am Sequential methods using TEVA/UTEVA/TRU Resin in F Area Process Lab (alpha, TIMS, ICP-MS) –Sequential Pu/Am/ Sr using TRU/SR Resin in Bioassay Lab New Applications –Sequential column extraction in Bioassay Lab to replace anion resin methods for Pu,Np and U plus enhanced Sr method using cartridge technology –UTEVA for Pu/U removal for Pu/U oxides (Impurity assay) –Actinides in soil using Diphonix Resin-microwave digestion
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Bioassay Application Current methods –Pu-acidified 500 mL samples/evaporated -AG-1 anion resin –U-acidified 50 mL samples/evaporated -AG-1 anion resin –Pu/Am/Sr- 500 mL calcium phosphate/ TRU + SR Resin Need more efficient, consistent, sequential methods; larger aliquots for special samples
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Bioassay Application Sherrod L. Maxwell, David J. Fauth, Gerald D. Levi New Methods –Expand use of calcium phosphate precipitation (500 ml to 1000+ mL) –Enhance vacuum column extraction with cartridge work –Pu (Np when Pu-236 tracer used) on TEVA –U on UTEVA –Pu, (Np)/U using TEVA/UTEVA cartridge technology –Pu, (Np)/Sr using TEVA/Sr cartridge technology
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Bioassay Application Advantages –Faster, more consistency, less acid waste; reduced labor costs; facilitates sequential analysis; better alpha peak resolution –Better detection limit for uranium-500 mL+ sample (vs. current 50 mL sample size) –Cartridge technology more efficient; eliminates large sequential load solutions (evaporation steps)
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Challenges Optimize nitrate levels for Pu, Np on TEVA and U, Sr UTEVA/SR Resin work using cartridges Achieve adequate Th-228 removal for Pu/U work Interface with current electroplating practices (Phase II, go to cerium fluoride precipitation)
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Bioassay Implementation Status Final testing near completion Implementation over next 3 to 4 months Pu-TEVA Pu, Np -TEVA Pu, (Np)-Sr -TEVA/SR Resin Pu, (Np)-U -TEVA/UTEVA
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Sample Preparation Tracer addition (Pu-242 or Pu-236, U-232) Routine calcium phosphate precipitation –3 mmol Ca (120 mg )+ 15 mmol (NH 4 ) 2 HPO 4 Precipitate/centrifuge/redissolve/ash Redissolve in 6 mL of 6M HNO 3 Add 2.5 M Al(NO 3 ) 3 -scrubbed using UTEVA –7.5 mL for for Pu, Np or Pu, Np/U –5 mL for Pu, Np/Sr Valence adjust Pu and Np: 1; ferrous sulfate 1mL 1.5 M FeSO 4. 2; sodium nitrite (1mL of 3M NaNO 2 )
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Sample Preparation (contd.) Add 16M HNO 3 as appropriate to increase acidity of load solution –1 mL for Pu, Np/U(adjust acidity to 2.5 to 3.5M) –2 mL for Pu, Np/Sr (adjust acidity to 4.5-5M)
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Pu, Np/U Using TEVA/UTEVA RESIN
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Pu-Recoveries Using TEVA/UTEVA Resin 500 mL urine sample/ Pu-242 tracer= 1.25 dpm %Recovery (microprecipitation) % Recovery (Electroplating* ) 1)1101) 84.4 2) 93.32) 72.4 3)92.63) 69.3 4) 95.24) 69.6 5) 101.55) 79.8 6) 99.36) 84.5 7) 97.7 7) 79.1 8) 115.48) 85.5 9) 107.99) 84.8 10)106.8 Avg. =102% Avg. = 79% *Add 4 mL 0.02M H2SO4 to enhance F removal during solution cleanup
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U Recoveries Using TEVA/UTEVA Cartridge 500 mL urine sample / U-232 tracer= 0.582 dpm % Recovery (Electroplating*) 1) 77.1 2) 84.5 3) 95.5 4) 75.9 5) 73.5 6) 71.1 7) 65.0 8) 74.7 9) 88.0 10)106.2 Avg. =81% * Used 0.02MHCl-0.02MHF instead of 0.02M H2SO4 for electroplating
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Pu/Sr Using TEVA/SR Resin
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Sr Recoveries using TEVA/Sr Cartridge 500 mL urine sample Sr-90 spiked in samples: 206 dpm Measured dpm % Recovery 180 87.4 17987.9 18991.7 17986.9 19795.6 Avg 18589.7 Sr-90 Spiked after precipitation: Measured:% Recovery 215104% 216105%
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Pu/U Removal for Impurity Assay Sherrod L. Maxwell, Sheldon. T. Nichols, Vernon Jones, Maureen Schilb Background AG MP-1 Anion Resin for Pu Removal prior to ICP-AES 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 resin –Increased need to analyze mixed Pu/U materials requiring Pu/U removal UTEVA Resin offers improved impurity recovery and removes Pu and U
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UTEVA Removal of Pu and U UTEVA Resin (diamylamylphosphonate) –Recovers all impurities except Au* –Zr, Ta, Hf, Nb require dilute HF in column load 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 Load solution: 10 mL 8 M HNO3-0.04M HF Column Rinse: 14 mL 8M HNO3 (optional with HF) (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., balancing Si background at ICP-torch due to HF) Adjust to 25 mL in graduated tube Pu/U recovery from resin: 20 mL 0.1M HCl-0.05M HF Status: In Use
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Analysis of CRM-124 Uranium Oxide Standards ElementMeasured Ref. Prepared Value/ %Difference (ppm) dc arc range (ppm) Al102105(81-120)-3% Be11.612.5 (10-17)-7% Cr55.4 52 (50-64)+6% Mg 52.451 (37-86)+3% Mo53.7 50 (30-50)+7% Na 230 200 (189-252)+15% Ni 106102 (92-158)+4% V 24.2 25 (23-30)-3% W105 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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Actinide Recovery Method for Large Soil Samples Sherrod L. Maxwell and Sheldon. T. Nichols Eliminate sample matrix using Diphonix Resin (load in HCL-HF) Microwave Diphonix Resin to release actinides Apply sequential actinide analysis using TEVA/UTEVA+ TRU Resins, followed by Am-REE on TEVA Resin Successfully applied to 10 gram soil fusions/leaches
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Summary New implementation of rapid column methods in bioassay lab will result in significant time/cost savings New use for UTEVA resin improves impurity analysis for Pu/U oxides/metals Diphonix resin eliminates matrix problems with large soil samples
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