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 Improvements
• SRS Environmental Monitoring lab
– faster water and air filter analysis for actinides
– improved soil-fecal sludge analyses (wastewater treatment plant
samples)
• SRS Bioassay lab
– improved Pu-Np column extraction for urine (better Pu
stripping/less volume)
– faster fecal analysis method (no microwave)
• Central Laboratory (process lab)
– improved Pu, Np in HEU and LEU samples
– TEVA + Pu-236 tracer
SRS Environmental Monitoring Lab
• Vacuum box systems and stacked cartridges
• Significant cost and time savings vs. gravity flow
• Tested both stacked UTEVA+ TRU and TEVA+TRU
methods
– both methods work very well; much faster than gravity flow
– eliminated evaporation of Am fraction: use 5 mL con HF
– use 50 ug cerium instead of 100 ug to improve peak resolution
SRS Environmental Monitoring Lab
• Showed stacked TEVA+TRU can be used on water
samples
– just like urine method- no iron interference
– may have some advantages for air filters (Po-210 interference)
• Po-210 can interfere with U-232 on UTEVA
– allows Pu AND Np together on TEVA
– use Ti (III) reductant in Pu strip from TEVA when performing
cerium fluoride microprecipitation
Pu, Np/Am, U, Sr on TEVA/TRU RESIN
(Water/Air filters)
1) Redissolve in 10 mL 3M HN03 - 0.5M Al(NO3)3
2) Add 0.5 mL 1.5M Sulfamic Acid + 1 mL 1.5M Ascorbic Acid
3) Add 1 mL 3.5M Sodium Nitrite
Rinse
20 mL 3M HN03
Th Removal
3mL 9M HCI/25mL
8MHCI
Pu Elution
20mL
0.10M HCl - 0.05MHF - 0.03M TiCl3
Add 0.5 mL 3M sodium nitrite
2mL TEVA Resin
(50-100 um)
Cerium fluoride
Alpha spectrometry
Remove TRU cartridge:
1) Elute Am with
15mL 4M HCI
2) Elute U with
10mL 0.1M ammonium
bioxalate
2.0mL TRU-Resin
(50-100 um)
Collect, evaporate, dissolve in 6M HNO3
Sr Resin
Pu-242 Tracer Recoveries
1000 mL water samples/ Pu-242 tracer= 4.40 dpm
Calcium phosphate precipitation
% Pu242 Recovery
UTEVA+TRU Method
% Pu242 Recovery
TEVA+TRU Method
1)
2)
3)
4)
101
106
106
108
1)
2)
3)
4)
5)
6)
99.3
105
105
109
98.6
102
105% (2.8% @1s)
Avg. =
103% ( 3.8% @1s)
Avg. =
Am-243 Tracer Recoveries
1000 mL water samples/ Am-243 tracer= 3.84 dpm
Calcium phosphate precipitation
% Am-243 Recovery
UTEVA+TRU Method
% Am-243 Recovery
TEVA+TRU Method
1)
2)
3)
4)
5)
6)
105
100
91.5
98.7
102
106
1)
2)
3)
4)
5)
6)
98.4
99.0
107
100
106
105
101% (5.2% @1s)
Avg. =
103% ( 3.8% @1s)
Avg. =
U-232 Tracer Recoveries
1000 mL water samples/ U-232 tracer= 5.45 dpm
Calcium phosphate precipitation
% U-232 Recovery
UTEVA+TRU Method
% U-232 Recovery
TEVA+TRU Method
1)
2)
3)
4)
5)
6)
92.9
98.2
96.2
94.9
91.6
93.2
1)
2)
3)
4)
5)
87.5
93.5
97.4
92.4
94.0
94.5% (2.6% @1s)
Avg. =
93.0% ( 3.8 % @1s)
Avg. =
SRS Environmental Monitoring Lab
• Actinides in soil-fecal samples
– dissolution and column flow problems with current method
– need total dissolution/eliminate flow problems & low uranium
– use Diphonix resin technology as in bioassay lab
• Initial testing encouraging
• Use sodium peroxide/sodium hydroxide fusion (Zr crucibles)
• Precipitate actinides as hydroxides; redissolve in HCL-HF/also boric
acid fraction
• 4 mLs Diphonix Resin + small volume HEDPA strip (15-20 mLs)
• Faster HEDPA destruction method (no microwave)
– modified Fenton’s Reagent method
• Routine size Eichrom columns
Diphonix Stripping-HEDPA
0.5M HEDPA
Strip Volume
1) 3 mL resin
2) 4 mL resin
3) 4 mL resin
4) Direct -HEDPA
15 mL
15 mL
20 mL
20 mL
Avg=
% Pu242
Tracer
104
99
105
113
105 %
% U232
Tracer
96
97
84
113
98 %
Redissolve in 10 mLs 6M HNO3 and 10 mls 2.5M aluminum nitrate (to avoid
phosphate interference), then TEVA+ TRU Column extraction
Soil-Fecal Sludge Samples
Pu-242
% Recovery
1) 101%
2) 69 %
3) 84%
4) 49 %
Avg= 76%
Pu-238
pCi/g
0.435
0.484
0.442
0.448
0.452 (4.8% @1s)
Pu-239/240
pCi/g
2.18
2.33
2.07
2.39
2.24 (6.5% @1s)
Soil-Fecal Sludge Samples
U-232
% Recovery
1) 56%
2) 75 %
3) 74%
4) 98 %
Avg= 76%
U-234
pCi/g
6.16
5.44
5.28
4.44
5.33 (13% @1s)
U-235
pCi/g
U-238
pCi/g
0.355
0.351
0.346
0.253
0.326 (15% @1s)
5.56
4.76
5.04
3.98
4.84 (14% @1s)
Soil-Fecal Sludge Samples
Am-243
% Recovery
1) 73%
2) 53 %
3) 64%
4) 38 %
Avg=57%
Am-241
pCi/g
0.746
0.684
0.620
0.670
0.679 (7.6% @1s)
Cm-244
pCi/g
0.506
0.506
0.462
0.378
0.464 (13% @1s)
Bioassay Lab Improvements
• Actinides and Sr-90 in urine
–
–
–
–
stacked TEVA+TRU Resin cartridges with vacuum boxes
Pu-236 tracer for Pu and Np at same time
Pu, Np (TEVA) and U, Am (TRU)
Sr (Sr Resin)
• Pu stripping improvement:
– improved Pu stripping with rongalite instead of iodide in strip
solution (less volume/faster flow rate)
– rongalite (sodium formaldehyde sulfoxylate)
– compatible with electroplating
– adjust bisulfate added for sulfate added from rongalite
decomposition (2.5 mLs 10 % bisulfate instead of 3 mLs)
Urine Batch: Calcium Phosphate Precipitation
Pu, Np/Am, U, Sr on TEVA/TRU RESIN
(URINE)
1) Redissolve in 12 mLs of 3M HN03 - 1M Al(NO3)3
2) Add 0.5 mL 1.5M Sulfamic Acid + 2 mls 1.5M Ascorbic Acid
3) Add 2 mLs 4M Sodium Nitrite
Rinse
20 mL 3MHN03
Th Removal
5mL 9M HCI/
25mL 8M HCI
Pu Elution
20mL
0.10M HCl - 0.05M HF - 0.015M Rongalite
2mL TEVA Resin
(50-100 um)
4mls 0.02M H2SO4 + 3mls 16M HN03
Evaporate/ash
Electrodeposition
Remove TRU cartridge:
1) Elute Am with
15mL 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
Pu-236 Recoveries-Urine
Using TEVA/Rongalite
Pu-236=0.426 dpm
500 mL urine
Avg Recovery=99%
160
140
120
100
80
60
40
20
0
1
2
3
4
5
6
7
8
9
10 11 12 13 14 15 16 17 18 19 20
Spiked Urine Samples: Rongalite Test
Known values:
Pu-238 =0.110 dpm/L
Pu-239 =0.857 dpm/L
Np-237=0.535 dpm/L
Avg. measured:
Pu-238 =0.143 dpm/L
Pu-239 =0.848 dpm/L
Np-237=0.508 dpm/L
1
0.9
0.8
0.7
0.6
Pu-238
0.5
Np-237
0.4
Pu-239
0.3
0.2
0.1
0
1
2
3
4
5
6
7
8
9
10
Bioassay Lab Improvements
• Bioassay: fecal method
–
–
–
–
–
wet ashing and dissolution in HCL-HF
Diphonix Resin
TEVA+TRU Resin
cartridges not stacked due to possible iron
previously evaporated load plus rinse from TEVA then redissolved,
added reductant and loaded onto TRU
– Pu, Np (TEVA) and U, Am (TRU)
– Sr (Sr Resin)
Recent Improvements in Fecal Method
• Improvements:
– no evaporation of load solution from TEVA to save time
• collect load plus minimal rinse from TEVA
• add sulfamic acid + ascorbic acid and load to TRU resin
– improved Pu stripping with rongalite instead of iodide in strip
solution
– Also testing:
• use of HEDPA strip of Diphonix instead of microwave (minimize
HEDPA to minimize phosphate and increase Al in final load solution)
• Use sodium peroxide/sodium hydroxide fusion instead of wet ashing
Microwave Digestion of Diphonix: Fecal Method
Testing using 15 mL strip with 0.04M
Rongalite; acidify to 3M HNO3, add
Al(NO3)3 and nitrite and load to
second TEVA column
Collect load and small rinse
ONLY: Eliminated evaporation
5
Pu on TEVA Resin-Fecal
(2nd Column to Remove all Th-228)
• Adjust acidity of 15 mL strip solution to 3M HNO3 using 4 mLs 16M
HNO3
• Add 1 mL of 2.5M aluminum nitrate
• Add 1mL 3.5 M Sodium Nitrite
Rinse
10mL 3MHN03
Th Removal
3mL 9MHCI/7mL
8MHCI
Pu Elution
20 mL
0.10MHC1 - 0.05MHF - 0.015M rongalite
1mL TEVA Resin
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
• SRS Environmental Monitoring lab work
– Vacuum box technology reduced method time by about 50%
– Diphonix-HEDPA may help with difficult soil-fecal samples
• Bioassay lab
– Improved Pu stripping using rongalite (85% to 99%)
– HEDPA to eliminate microwave in fecal analysis
• Process lab
– Pu-236 tracer use for Pu, Np in process lab on high uranium
samples