Transcript Technical Updates on UTEVA, TEVA and TRU Resins Eichrom Technologies, Inc.
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 HNO 3 /1M Al(NO 3 ) 3. with 2 mL of 0.6M Ferrous sulfamate and 200 mg of ascorbic acid .
2) Rinse sample beaker with 5 mL of 3M HNO 3 3) Rinse column with 5 mL of 3M HNO 3 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 Ferrous
210 Pb/ 210 Po spike (1100 pCi) Method Ferrous Activity in U Region (dpm) 230 No ferrous 3.5
Effect of Additional 3M HNO 3 210 Pb/ 210 Po spike Rinse Additional Rinse (mL) 0 10 20 30 Activity in Uranium Region (dpm) 92 pCi spike no ferrous 1080 pCi spike ferrous 3.0
230 1.6
- 0.23
- - 28
Effect of Uranium Strip Solution no ferrous added 210 Pb/ 210 Po spike (1100 pCi) Uranium Strip Solution 0.01M HCl 0.1M HCl 1M HCl Activity in Uranium Region (dpm) No ferrous 3.5
ferrous 230 1.3
0.16
- 1.84
Additional Rinse/1M HCl Strip Combo Method Original procedure 30 mL HNO 3 Rinse only 1M HCl Strip only 30mL rinse + 1M Strip Activity in Uranium Region (dpm) 230 28 1.84
1) Load sample on UTEVA with 10 ml of 3M HNO 3 /1M Al(N0 3 ) 3 with 2 mL of 0.6M Ferrous sulfamate and 200 mg of ascorbic acid 2) Rinse sample beaker with 5 mL of 3M HNO 3 3) Rinse column with 5 mL of 3M HNO 3 4) Rinse column with 10 mL of 3M HNO 3 (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 A good decontamination of Po-210 in U-232 region can be achieved by additional 3M HNO 3 rinse on UTEVA and eluting uranium selectively with 1M HCl • 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. • Solid samples are digested and dissolved finally in 20 ml of 0.1M HNO 3 • 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. • Spiked 20 ml of 0.01M HNO 3 U-234/238 with ~2000 dpm of • Load on TEVA Resin column • Rinse with 25 ml of 0.1M HNO 3 • Extrude resin in LSC vial • Added 15 ml of cocktail and count • Use of fluoride to complex the residual Th-234 on the column • Two fluoride solutions tested: – Hydrofluoric acid – Sodium fluoride • Spiked 20 ml of 0.01HNO 3 with ~2000 dpm of U-234/238 • Load on TEVA Resin column • Rinse with 5 ml of 0.1M HNO 3 • Rinse with 25 ml of 0.5M HF/0.02M HNO 3 OR with 25 ml of 1M NaF/0.02 HNO 3 • Rinse with 5 ml of 0.1M HNO 3 • Extrude resin in LSC vial • Added 15 ml of cocktail and count BWXT’s ProcedureTest Results Rinse volume used=25 mL TEVA Lot # 0.1M HNO 3 (CPM) TEA06309 72 0.5M HF /0.02M HNO 3 (CPM) 14.84 18.9 13.1 1M NaF /0.02M HNO 3 (CPM) Not tested 15.36 TE0K TEVA Cl form Blank 24.5 14.7 + 0.9 15.36 14.7 + 0.9 15.0 14.7 + 0.9 • 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 1) TRU Resin 2) TRU Resin with a ‘post’ Prefilter layer 1) Spike 10 ml of 3M HNO 3 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 HNO 3 4) Rinse with 5ml of 0.5M HNO 3 5) Strip Am with 9M + 4M HCl Four different preparation prior to CeF 3 ppt. – 1) Digested with Aqua-regia – 2) Undigested – 3) Changed molarity (~0.5 M HCl) – 4) Digested with 10% H 2 SO 4 Resin Type TRU Am Strip Solution 9M HCl + 4M HCl Digested with Aqua regia 89 % + 3% No digestion 48 % + 3% Changed molarity 97 % + 7% Digested with H 2 SO 4 84 % + 6% TRU with prefilter layer 9M HCl + 4M HCl 89 % + 5% 62 % + 5% 97 % + 3% 82 % + 23% Resin Type TRU Am Strip Solution 9M HCl + 4M HCl TRU with prefilter layer 9M HCl + 4M HCl Changed molarity First Run 97 % + 7% Changed molarity RERUN 93 % + 10% 97 % + 3% 95 % + 4% • 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 6) Evaporate Am fraction to dryness 7) Add 0.5 ml of conc. HCl and dilute to 15 ml of DI water 8) Perform CeF 3 ppt. Resin Type UTEVA / TRU Am Strip Solution 9M HCl + 4M HCl UTEVA / TRU with prefilter layer 9M HCl + 4M HCl Changed molarity 89 % + 10% 89 % + 11% • Am recoveries improved by changing the concentration on HCl prior to CeF 3 • TRU resin cartridge performed well once the HCl concentration was changed Revised Procedure
Summary
TEVA Column: Tc-99 Issues
BWXT’s Tc-99 Procedure
BWXT’s Procedure tested at Eichrom
Possible Solutions for Decontamination
Decontamination of Th-234
Conclusion
TRU Resin Cartridges
Am-243 Spike Test
Cerium Fluoride Precipitation
Am-243 recoveries (n=4)
RETEST: Am-243 recoveries (n=4)
ACW03 tested for Am
ACW03…continued
Tap Water: Am-243 recoveries (n=5)
Conclusion