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Technical Updates on UTEVA, TEVA and TRU Resins. Anil Thakkar & Michael Fern Eichrom Technologies, Inc. Paris May 14, 2002. Topics. UTEVA Resin: Decontamination of Po-210 U-232 yields TEVA Resin: Decontamination of U-nat/Th in Tc-99 region TRU Resin: Am recoveries.
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Technical Updates on UTEVA, TEVA and TRU Resins Anil Thakkar & Michael Fern Eichrom Technologies, Inc. Paris May 14, 2002
Topics • UTEVA Resin: • Decontamination of Po-210 • U-232 yields • TEVA Resin: • Decontamination of U-nat/Th in Tc-99 region • TRU Resin: • Am recoveries
U-232 Yields • Unrealistic high U-232 yields reported with UTEVA resin in samples with high in Pb-210
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
Effect of Uranium Strip Solution no ferrous added210Pb/210Po spike (1100 pCi)
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
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
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.
BWXT’s 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.
BWXT’s 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
Possible Solutions for Decontamination • Use of fluoride to complex the residual Th-234 on the column • Two fluoride solutions tested: • Hydrofluoric acid • Sodium fluoride
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 HNO3OR with 25 ml of 1M NaF/0.02 HNO3 • Rinse with 5 ml of 0.1M HNO3 • Extrude resin in LSC vial • Added 15 ml of cocktail and count
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
TRU Resin: History • Historical problems with Am recoveries from TRU Resin (HCl strip.) • Suspected Extractant Leaching handled with wet ashing of HCl Strip Solution
TRU Resin Cartridges 1) TRU Resin 2) TRU Resin with a ‘post’ Prefilter layer
Am-243 Spike Test 1) Spike 10 ml of 3M HNO3 with 6.52 dpm of Am-243 2) Load solution on TRU cartridges (assisted with VBS, flow rate 1ml/min) 3) Rinse with 10 ml of 3M HNO3 4) Rinse with 5ml of 0.5M HNO3 5) Strip Am with 9M + 4M HCl
Cerium Fluoride Precipitation Four different preparation prior to CeF3 ppt. • 1) Digested with Aqua-regia • 2) Undigested • 3) Changed molarity (~0.5 M HCl) • 4) Digested with 10% H2SO4
ACW03 tested for Am • 0.5 L of Eichrom tap water spiked with Am-243 • Precipitated Am with calcium phosphate • Scavenge ppt. and dissolve in the load solution • Followed ACW03 procedure using UTEVA/TRU cartridges • Collect Am fraction
ACW03…continued 6) Evaporate Am fraction to dryness 7) Add 0.5 ml of conc. HCl and dilute to 15 ml of DI water 8) Perform CeF3 ppt.
Conclusion • Am recoveries improved by changing the concentration on HCl prior to CeF3 • TRU resin cartridge performed well once the HCl concentration was changed