Recent Improvements in Rapid Column Separation Methods at SRS

S. L. Maxwell, III, D. J. Fauth, R. C. Henderson, J. J. Smiley, S. R. Johnson

Westinghouse Savannah River Site

Recent Column Extraction Applications

• Column Extraction Applications at SRS– Soil and Fecal Sample Analyses

• Actinides in soil using Diphonix Resin-microwave digestion – S.L. Maxwell III and S. Nichols, “Actinide Recovery Method for Large

Soil Samples”, Radioactivity and Radiochemistry, 11, No 4, 46, (2000)

• Pu, Am in fecal samples using Diphonix Resin-microwave digestion and TEVA+TRU Resin, (1999)

– S.L. Maxwell and D. Fauth, “New Fecal Method for Pu and Am”, Journal of Radioanalytical and Nuclear Chemistry, Vol. 250, No. 1 , 2001

Recent Column Extraction Applications

• Column Extraction Applications at SRS, contd.

– Bioassay: urine• Column extraction in Bioassay Lab for Pu, Np, Am, U plus Sr method

using cartridge technology – S.L. Maxwell III and D. Fauth, “Rapid Column Extraction Methods for Urine”,

Radioactivity and Radiochemistry, 11, No 3, 28, (2000)

Bioassay Urine Methods

• Improve chemical recoveries, improve Th-228 removal and reduce labor costs/rework– Pu (+Np when Pu-236 tracer used) on TEVA Resin

– Pu, Np, U, Am, Sr • Single two cartridge TEVA/TRU column plus SR Resin

• No iron in urine allows novel, stacked TEVA+TRU column

• Pu, Np on TEVA; U, Am on TRU cartridge in stacked column

• Sr collected, evaporated, redissolved, separated on SR Resin column

Urine Batch: Calcium Phosphate Precipitation

Pu, Np/Am, U, Sr on TEVA/TRU RESIN (URINE)

Rinse20 mL 3MHN03

Th Removal3mL 9MHCI/30mL

8MHCI

Pu Elution30mL

0.10MHC1 - 0.05MHF - 0.1M NH4l

1) Adjust to 2.5MHN03 - 1M Al(NO3)3

2) 0.05M Sulfamic Acid + 0.2M Ascorbic Acid3) 0.4 to 0.5M Sodium Nitrite

Remove TRU cartridge:1) Elute Am with

12mL 4M HCI2) Elute U with

20mL 0.1M ammoniumbioxalate

2mL TEVA Resin(50-100 um)

2.0mL TRU-Resin(50-100 um)

Collect, evaporate, dissolve in 6M HNO3SR Resin

Electrodeposition

4mls 0.02M H2SO4 + 3mls 16M HN03

Evaporate/ash

TEVA+ TRU Stacked Column: Pu, Np, U, Am

TRU Cartridge: U, Am Stripping

SR Cartridge: Sr-90 Separation

TEVA Pu Tracer Recoveries

500 mL urine sample/ Pu-242 tracer= 1.25 dpm / One TEVA Column Fe+AA/+NO2

%Recovery (CeF3 microprecipitation) % Recovery (Electroplating* )

1) 110 1) 84.4

2) 93.3 2) 72.4

3) 92.6 3) 69.3

4) 95.2 4) 69.6

5) 101.5 5) 79.8

6) 99.3 6) 84.5

7) 97.7 7) 79.1

8) 115.4 8) 85.5

9) 107.9 9) 84.8

10) 106.8 10) 77.0

11) 101.6 11) 82.5

12) 102.6

Avg. = 102.0% (7.0% @1s) Avg. = 79.0 (6.2% @1s)

*Add 4 mL 0.02M H2SO4 to enhance F removal during solution cleanup for plating

TEVA- Np-237 , Pu-236 Recoveries

500 mL urine sample/ Np-237 spike= 1.40 dpm/Pu-236=0.425 dpm

Single TEVA column (CeF3 microprecipitation)

% Pu-236 % Np-237

Recovery Recovery

1) 94.0 ***

2) 92.5 ***

3) 101 ***

4) 100 ***

5) 111 ***

6) 91.0 88.1

7) 91.9 86.7

8) 105 102.9

9) 109 102.0

10) 88.9 94.2

Avg. =98.4% (7.9% @1s) Avg. = 94.8% (7.6% @1s)

Additional bias comparison on 24 samples: -1.49% +/- 6% estimate of bias

Bioassay Lab Alpha Counters

Bioassay Lab Gas Proportional Counters:Sr

%bias Np Control Samples

-80%

-60%

-40%

-20%

0%

20%

40%

60%

80%Bias = -2.5% RSD = 11.0 June 2000 - January 20023067 samples

TRU Resin -Am Tracer Recoveries

500 mL urine sample/ Am-243 tracer= 1.55 dpm / TRU cartridge after TEVA SA+AA/+NO2 / load TEVA and TRU at same time/remove TRU cart./elute Am

% Am-243 Recovery (Electroplating)1) 93.2

2) 92.1

3) 107.4

4) 70.3

5) 102.4

6) 103.0

7) 100.2

8) 103.3

9) 102.6

10) 94.7

Avg. = 96.9% (10.6% @1s)

Microwave Digestion of Diphonix: Fecal Method

2

Pu on TEVA RESIN(2nd Column to Remove all Th-228)

• Redissolve in 7.5mL 3M HN03 + 1mL 2.5M Al(NO3)3

• Add 0.5mL 1.5M Ferrous Sulfate + 1mL 1.5M Ascorbic Acid• Add 1mL 3.5M Sodium Nitrite• Add 1mL 16M Nitric Acid

Th Removal3mL 9MHCI/7mL

8MHCIRinse

10mL 3MHN03

Pu Elution20 mL

0.10MHC1 - 0.05MHF - 0.1M NH4l

1mL TEVA Resin

% Bias Plot for DOELAP Proficiency Test

-40.0

-20.0

0.0

20.0

40.0

60.0

Pu-238 Pu-239 /240 U-234 U-238 Np-237 Am-241 Sr-90

% B

ias

Urine %Bias Fecal %Bias Acceptable Lower % Acceptable Upper %

% RSD Plot for DOELAP Proficiency Test

0.0

10.0

20.0

30.0

40.0

50.0

Pu-238 Pu-239 /240 U-234 U-238 Np-237 Am-241 Sr-90

% RS

D

Urine %Bias Fecal %Bias Acceptable Upper % Acceptable Upper %

UTEVA Pu/U Removal for Metals Assay at Savannah River

• 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

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

Average Column Spike RecoveriesICP-MS

Element % Recovery Element % Recovery Element % Recovery

Ag 106 Hf 90 Se 87

Al 101 Hg 77 Si 132As 88 K 102 Ta 84B 89 La 108 V 104Ba 106 Li 101 W 113Be 90 Mg 103 Zn 91Ca NA Mo 101 Zr 63Cd 94 Na 98Ce 108 Nb 98Cr 103 Ni 103Cu 106 P 154Fe 106 Pb 99Ga 101 S NA

Process Lab Improvements

• Process samples to support HEU Blenddown processing

• Improvements:– Pu and Np are key product specification measurements

– Pu-236 tracer for Pu and Np on TEVA resin in HEU and LEU process solutions

– 1 mL TEVA cartridges to ensure total Th-228 removal (separated twice on TEVA)

– use Ti (III) reductant in Pu strip from TEVA

Summary

• New rapid column extraction methods have greatly improved radiochemical separation technology– process lab support

– bioassay lab applications

– environmental lab work

• Vacuum-enhanced column and cartridge extraction methods have enhanced lab capabilities– simpler, faster, less rework, less waste

• Rapid extraction technology continues to advance at the frontier of radioanalytical chemistry