Th, Pu & U Separation Using TEVA and UTEVA Resin Eichrom Workshop at RRMC 12 November, 2002 Knoxville, TN

Objective To develop a quick method for the separation of Th, Pu and U in water samples

Tracers U232 tracer cleanup required to remove daughter Th228 Followed David Sill (NAREL)’s BaSO4 procedure Pu242 and Th229 used for plutonium and thorium Pu236 better choice if Np measurement is required

Sample Preparation 1 liter aliquots of acidified water samples were spiked with Th229, Pu242 and U232 tracers Samples were heated to near boiling for 2 hours A Ca3(PO4)2 precipitation was performed Decant supernatant, centrifuge and collect the precipitate

Load Solution Dissolve precipitate in 3M HNO3/1M Al(NO3)3 solution Add ferrous sulfamate and NaNO2 Load on TEVA and UTEVA Resin cartridge in tandem

Proposed Procedure 1) Attach TEVA resin and UTEVA resin cartridges in tandem 2) Load 10 ml of 3M HNO3/1M Al(N03)3. with 2 mL of 0.6M Ferrous sulfamate followed with 1 ml of 3M NaNO2 3) Rinse sample beaker with 5 mL of 3M HNO3 4) Rinse cartridge with 5 mL of 3M HNO3 5) Separate TEVA and UTEVA cartridges

Proposed Procedure continued TEVA cartridge 1) Rinse with 30 ml of 3M HNO3 2) Elute Th with 20 ml of 9M HCl and 5 ml of 6M HCl 3) Elute Pu with 20 ml of 0.02M TiCl3/0.05M HCl/0.05M HF (Np eluted in this fraction)

Proposed Procedure continued UTEVA Cartridge 1) Rinse with 5 ml of 9M HCl 2) Elute U with 15 ml of 1M HCl

Direct Spike Results (Proposed Procedure)

U fraction contaminated with Pu

Improvements Needed Possible Pu valence adjustment for better recoveries U recoveries need to be higher Better decontamination for U fraction

Possible Solutions for Improvements 1) Use 2 ml of ferrous sulfamate + 0.5 ml of NaNO2 2) Use 1 ml of ferrous sulfamate + 1 ml of NaNO2 3) Increase U and Pu strip volumes 4) Add oxalic acid rinse on UTEVA

Direct Spike Results (2 ml of Ferrous+0.5ml of NaNO2 ) * With 25 ml of Pu strip volume **With 20 ml of U strip volume & oxalic acid rinse

Direct Spike Results (1 ml of Ferrous + 1ml of NaNO2) *With 25 ml of Pu strip volume **With 20 ml of U strip volume & oxalic acid rinse

Revised Procedure 1) Load sample on TEVA resin and UTEVA resin cartridges in tandem with 10 ml of 3M HNO3/1M Al(N03)3. with 1.0 mL of 0.6M ferrous sulfamate and 1 ml of 3M NaNO2 2) Rinse sample beaker with 5 mL of 3M HNO3 3) Rinse cartridge with 5 mL of 3M HNO3 4) Separate TEVA and UTEVA cartridges

ACW13 continued TEVA cartridge 1) Rinse with 5 ml of 3M HNO3 3) Elute Th with 20 ml of 9M HCl and 5 ml of 6M HCl 4) Elute Pu with 25 ml of 0.02M TiCl3/0.05M HCl/0.05M HF (Np will be present in this fraction)

Revised ACW13 continued UTEVA Cartridge 1) Rinse with 5 ml of 3M HNO3 2) Rinse with 5 ml of 9M HCl 3) Rinse with 20 ml of 5M HCl/0.05M oxalic acid 4) Elute U with 20 ml of 1M HCl

Decontamination Test ~100 pCi of Am, Np, Th, Pu and U were added to the load solution Solution was processed following ACW13

Decontamination Factors

DI Water

Th229 Spectrum

U232 Spectrum

Pu242 Spectrum

Tap Water

Summary Benefits Drawbacks A quick method with consistent, reproducible recoveries Rugged enough to provide good decontamination from other actinides Drawbacks Th228 cleanup required Pu236 tracer required if Np237 measured