On-line Actinide Quantification with Extractive Scintillating Resins
Timothy A. DeVol, James E. Roane, Lara D. Hughes
Clemson University
Eichrom Users’ Group Workshop
May 4, 2004
Need for Monitoring Method
• Radionuclide contamination in natural waters– natural– anthropogenic
• Radionuclide specific and gross alpha analyses – primarily laboratory based– can be time intensive and costly
• Need for in-situ and on-line monitoring – site assessment before, during and following remedial action
Sample SamplePrep
Concentration
Separation
Detection
Data
Sample SamplePrep
ConcentrationSeparation Detection Data
Dual FunctionalitySimultaneous Concentration and Detection
Heimbuch, et al., 1964
Li and Schlenoff, 1994DeVol, et al., 1997Campi, et al., 1998Link and Synovec, 1999Egorov, et al., 1999Headrick, et al., 2000
Extractive Scintillating Resin
Inert polystyrene chromatographic supports
(100 - 150 m particle size, ~700 m2/g)
Resin Fluor Extractant
TRU ES PPO/DM-POPOP CMPO/TBP
Actinide ES -NPO Dipex®
Experimental- Flow cell procedure• Flow cell
– resin dry packed into FEP Teflon tubing – placed in front of PMT(s)
• Test procedure– conditioning, loading and washing steps with appropriate reagents– collecting on-line data during flow – pulse height spectra before and after load– aliquots of effluent analyzed off-line (mass balance)
• Radioactivity– spiked solutions of 241Am, 239Pu and 233U– Anthropogenic samples– natural groundwater containing U
Extractive Scintillator in
Flow-cellRadiation Detector
Computer
Effluent
Sam
ple
Load
ing
Sol
utio
n
Elu
ant
LSC
Simultaneous Separation and Detection
Manually controlled pump
Flow-Cell Detection Systems
Ultraviolet Illumination
Coincidence System for TRU ESModified Hidex Triathler for Actinide ESModified Eberline E-600 for Tc ES II
TRU ES Loading Profile
0
2
4
6
8
10
12
0 500 1000 1500 2000
Gro
ss C
ou
nt R
ate
(cp
s)
Time (sec)
I II III
I Condition w/ 2 M HNO3
II Load 239Pu in 2 M HNO3
III Rinse w/ 2 M HNO3
0
10
20
30
40
50
60
0.0
0.5
1.0
1.5
2.0
2.5
3.0
0 100 200 300 400 500
239
Pu
Gro
ss C
oun
tsB
ackg
rou
nd
Co
unts
Channel Number
TRU ES Pulse Height Spectra
239PuBackground
0
20
40
60
80
100
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0 1000 2000 3000 4000 5000On-
Line
Gro
ss C
oun
t Rat
e (c
ps) O
ff-Line N
et Co
unt Rate (cp
s)
Free Column Volumes (FCV)
off-line 3H
on-line 233U off-line 233U
Chromatographic capacity of the ES TRU resin as illustrated by the loading and elution of 233U
k’ ~ 3000
Sequential Elution of 241Am, 239Pu and 233U from TRU ES Resin
Off-Line Counting
On-Line Counting
Sample Load in 2-M HNO3
4-M HCl
4-M HCl + 0.02-M TiCl32-M HCl0.1-M Ammonium Bioxalate
0
50
100
150
200
250
300
350
400
450
500
0 2000 4000 6000 8000 10000Time (s)
Net
Cou
nt R
ate
(cps
)
241Am 239Pu 233U
0
5
10
15
20
25
30
0 2000 4000 6000 8000 10000Time (s)
Gro
ss C
ount
Rat
e (c
ps)
239Pu,233U
241Am, 239Pu, 233U
233U
Analysis of SRTC High Level Waste Sludge
Plot of average activity (n=3) with 1 standard deviation
100
101
102
103
Gross An3+ Pu4+ U6+
On-line avg.Off-line avg
Con
cen
trat
ion
(Bq
mL-1
)
0.00
0.25
0.50
0.75
0.0 0.1 0.2 0.3 0.4 0.5 0.6
Gro
ss C
oun
t Rat
e (c
ps)
Volume (L)
On-Line Monitoring233U in Synthetic Groundwater
CR(cps) = 0.151 + 0.650*V(L) R= 0.95
CR(cps) = 0.165 + 4.631*V(L) R= 0.99
CR(cps) = 0.159 + 2.729*V(L) R= 0.97
8.62 Bq L-1
4.92 Bq L-1
1.74 Bq L-1
0.00
0.25
0.00 0.02 0.04 0.06 0.08 0.10
Gro
ss C
ou
nt R
ate
(cps
)
Volume (L)
Background
Monitoring Natural Uranium in Water
0.00
0.10
0.20
0.30
0.40
0.50
0.00 0.02 0.04 0.06 0.08 0.10 0.12
Gro
ss C
oun
t Ra
te (
cps)
Volume (L)
CR (cps) = 0.153 + 4.884*V(L) R=0.96Expected 7.48 Bq/LMeasured 9.6 Bq/L from slope of first 50 mL
125 mL sample acidified to 0.5 M HCl
Actinide ES Resin
0
2
4
6
8
10
12
14
0 200 400 600 800 1000
y = 1.1842 + 0.011822x R= 0.99584
Gro
ss C
ount
Rat
e (c
ps)
Volume (mL)
685 g U/L17.4 Bq/L
Actinide ES Resin
1
1.5
2
0 200 400 600 800 1000
Background 1.96 backgroundNPO 30 mg/L
y = 0.99462 + 0.00083531x R= 0.90612 G
ros
s C
ou
nt
Ra
te (
cp
s)
Volume (mL)
30 g uranium/L (0.76 Bq/L)
Natural Uranium in Groundwater acidified to pH 1
Summary of Results
Resin Detector Background Count Rate (cps)
Detection Efficiency
TRU ES Coincidence system
0.14 51% (nat. U) 97% (241Am)
Actinide ES Modified Hidex Triathler
0.75 52% (nat. U) 65% (241Am)
Conclusions• Extractive scintillating resins are selective dual-purpose
media– High
– Transparent to scintillation light
• Chromatographic property of ES resin is similar to non-scintillating commercially available resin
• Quantification has been demonstrated on-line• Applicable toward environmental screening applications.
Continuing to work on solving the stability, sensitivity, benign sample matrix, and reusability issues
FUTURE WORK
• Solve the problems that affect the results, such as,– Chemical luminescence– Dark adaptation time– Signal variation with radionuclide position in flow-cell
• Optimize flow-cell geometry for maximum sensitivity
• Develop ruggedize field instrument and demonstrate in the field
• Off-line evaluation procedures
Acknowledgments
Dr. James Harvey, Dr. Jonathon Duffey, and Joel Williamson at Eichrom Technologies, Inc.
NSF SBIR Phase I contract # NSF/SBIR-9760934
DOE Office of Science (BER) grant DE-FG07-99ER62888