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)
1) Adjust to 2.5MHN03 - 1M Al(NO3)3
2) 0.05M Sulfamic Acid + 0.2M Ascorbic Acid
3) 0.4 to 0.5M Sodium Nitrite
Rinse
20 mL 3MHN03
Th Removal
3mL 9MHCI/30mL
8MHCI
Pu Elution
30mL
0.10MHC1 - 0.05MHF - 0.1M NH4l
2mL TEVA Resin
(50-100 um)
4mls 0.02M H2SO4 + 3mls 16M HN03
Evaporate/ash
Electrodeposition
Remove TRU cartridge:
1) Elute Am with
12mL 4M HCI
2) Elute U with
20mL 0.1M ammonium
bioxalate
2.0mL TRU-Resin
(50-100 um)
Collect, evaporate, dissolve in 6M HNO3
SR Resin
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)
1)
2)
3)
4)
5)
6)
7)
8)
9)
10)
11)
12)
110
93.3
92.6
95.2
101.5
99.3
97.7
115.4
107.9
106.8
101.6
102.6
Avg. = 102.0% (7.0% @1s)
% Recovery (Electroplating* )
1)
2)
3)
4)
5)
6)
7)
8)
9)
10)
11)
84.4
72.4
69.3
69.6
79.8
84.5
79.1
85.5
84.8
77.0
82.5
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
Recovery
1)
2)
3)
4)
5)
6)
7)
8)
9)
10)
94.0
92.5
101
100
111
91.0
91.9
105
109
88.9
Avg. =98.4% (7.9% @1s)
% Np-237
Recovery
***
***
***
***
***
88.1
86.7
102.9
102.0
94.2
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
3067 samples
June 2000 - January 2002
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)
2)
3)
4)
5)
6)
7)
8)
9)
10)
93.2
92.1
107.4
70.3
102.4
103.0
100.2
103.3
102.6
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
Rinse
10mL 3MHN03
Th Removal
3mL 9MHCI/7mL
8MHCI
Pu Elution
20 mL
0.10MHC1 - 0.05MHF - 0.1M NH4l
1mL TEVA Resin
% Bias Plot for DOELAP Proficiency Test
60.0
% Bias
40.0
20.0
0.0
-20.0
-40.0
Pu-238
Urine %Bias
Pu-239 /240
U-234
Fecal %Bias
U-238
Np-237
Acceptable Lower %
Am-241
Sr-90
Acceptable Upper %
% RSD Plot for DOELAP Proficiency Test
50.0
% RSD
40.0
30.0
20.0
10.0
0.0
Pu-238
Urine %Bias
Pu-239 /240
Fecal %Bias
U-234
U-238
Acceptable Upper %
Np-237
Am-241
Acceptable Upper %
Sr-90
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 HCl0.05M HF
Average Column Spike Recoveries
ICP-MS
Element % Recovery
Ag
106
Al
As
B
Ba
Be
Ca
Cd
Ce
Cr
Cu
Fe
Ga
101
88
89
106
90
NA
94
108
103
106
106
101
Element % Recovery
Hf
90
Element
Se
% Recovery
87
Hg
77
Si
132
K
La
Li
Mg
Mo
Na
Nb
Ni
P
Pb
S
102
108
101
103
101
98
98
103
154
99
NA
Ta
V
W
Zn
Zr
84
104
113
91
63
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