Upload
giancarlo-blankinship
View
232
Download
0
Tags:
Embed Size (px)
Citation preview
ANALYTICAL SEPARATIONS GROUP
Megan Bennett, Ashlee Crable, Sherry Faye,
Narek Gharibyan, Julie Gostic, and Chris Klug
Subgroup Leader: Ralf Sudowe
Common Research Goals
Develop better separation schemas for various radioisotopes (Sr, An, Transactinides) in aqueous systems Basic Science Applications Environmental Emergency Response Nuclear Forensics
Sorption/Desorption Studies Characterizing various forms of
chromatographic separation procedures
Heavy Element Chemistry (Megan Bennett & Julie Gostic)
Chemical characterization of transactinides: elements 104 and 105
Studying the nuclear and chemical properties of the heavy elements or transactinides provides validation of predicted periodic trends and illustrates the importance of relativistic effects as a causality for deviations in periodicity.
Reaction Products
Target Nucleus
Projectile Compound Nucleus
Fission ProductsFigure adapted from presentations by Dawn Shaughnessy and Ken Moody
Hot Fusion
or
Element 104 & 105 Chemistry
Objective
Analytical Challenges Rapid Large number of exchange steps Highly Selective Continuous process Samples easily prepared for α spec
Investigation
Develop separation methods that will allow us to separate a few atoms from a sea of other constituents
Using Group IV/V chemical homologs, we can determine which extraction chromatography resins are the best candidates
Homolog Results
Group IV Batch Results Using DGA resin
Group V Batch Results Using DGA Resin
DGA Column Extractions
Sample Loading: 1.0 M HNO3/ 0.1 M HF, 1 mLStrip 1 (Pa): 0.4 M HNO3/0.2 M HF, 5 mL
Strip 2 (Ta): 8M HNO3/0.2 M HF, 6 x 5 mLStrip 3: 0.1 M Ammonium Bioxalate, 5 mL
Recovery >90% for all radionuclides.
MS-5 Fractional Radionuclide Activity Distribution
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
SampleLoad
Strip 1 Strip 2-1
Strip 2-2
Strip 2-3
Strip 2-4
Strip 2-5
Strip 2-6
Strip 3
Experimental Fraction
Act
ivit
y F
ract
ion
243Am 237Np 233Pa (182 Ta)Avg
Strip 2
Analysis of Bone Ash and other matrices(Ashlee Crable)
Developing more efficient separation methods for Sr and Actinides in various environmental matrices
Problem Statement
Preliminary Objective
The current analytical methods that exist for determining total strontium contamination in various matrices are greatly influenced by the presence of other matrix constituents such as calcium and phosphates. This presents a particular problem for determining total deposition in bone (hydroxyapatite).
To determine the separation efficiency of 90Sr using vacuum-assisted extraction chromatography (Sr·Spec resin cartridges) in the presence of Ca2+
SEM image of bone ash
LSC Bone Ash Runs (0 - 4 days)
0
100
200
300
400
500
600
700
LOAD RINSE STRIP
CP
M
0.1 M NIST
0.4 M NIST
0.8 M EBON
LSC results of spiked bone ash samples
Effect of bacteria on sorption of RN to soil (Sherry Faye)
Sorption of 241Am and 233U to Volcanic Tuff in the Presence of Shewanella oneidensis (MR-1)
Objectives:To obtain data on sorption kinetics, equilibrium and fundamental surface interactions of radionuclides to volcanic tuff, commonly found in the Southern Nevada areas of Yucca Mountain and the Nevada Test site.
To obtain a better understanding of surface interactions of the Shewanella oneidensis (MR-1) culture with tuff and radionuclides.
Results
% sorbed vs time
0102030405060708090
100
0.00 20.00 40.00 60.00 80.00
Time (h)
% s
orbe
d
U-233 + tuff
no tuff
10 4̂ cells/g
10 6̂ cells/g
10 8̂ cells/g
10 1̂0 cells/g
233U Sorption in the Presence of Shewanella
Tuff Surface Morphology using SEM
Measurement of neutron capture on Am-241 (Narek Gharibyan)
Objective
Nuclear reactions
Investigation
241Am
242Cm
IT
242Am β-
(n,γ) 141 y
16.02 h
162.8 d
Separation of curium from americium for neutron capture cross section and isomeric ratio measurements (242m+gAm from 241Am)
Am/Cm separation methods with extraction chromatography resins from Eichrom that would not require changing Am (III) oxidation state.
TEVA resin results
Effects of various nitrates (LiNO3, KNO3, NaNO3, Al(NO3)3, Mg(NO3)2, Ca(NO3)2) on Am/Cm separation:
N + NO3-
R
CH3
R
R
R = C8H17 and C10H21
Trialkyl, methylammonium
nitrate0
50
100
150
200
250
0.00 1.00 2.00 3.00 4.00 5.00 6.00
AmCm
k'
[LiNO3]
K’
Li(NO3)3
TRU resin results
Acid dependency (HNO3, HCl) on Am/Cm separation from various resins:
0
20
40
60
80
100
0.01 0.1 1 101
AmCm
k'
[HNO3]
P
O O
N
CMPO
P
O
OOO
TBP
Automated Rapid Separations(Julie Gostic)
Sr Elution System, Sr ResinSr Elution System, Sr Resin
Am/U Elution System, TRU ResinAm/U Elution System, TRU Resin
Pu, Np Th Elution System, TEVA Pu, Np Th Elution System, TEVA ResinResin
Sample Sample IntroductionIntroduction
Sample Sample Loading and Loading and RinseRinse
Separate Cartridge Separate Cartridge TraysTrays
Element-Specific Element-Specific Chemistry Chemistry
Start
TEVA TEVA
TRU TRUSr
LSC, GPC, MSLSC, GPC, MS
LSC, Alpha/Mass LSC, Alpha/Mass Spectrometry Spectrometry
Sample Preparation
http://www.jkem.com/spe.html
Laboratory Samples(3M HNO3-1 M Al(NO3)3, 1.5M Sulfamic and Ascorbic Acids, 3.5M NaNO2)
Discard Eluent
Am
12
3
4
TRU
TEVA
Discard Eluent
Discard Eluent
5
6
Pu6
5
TEVADisconnect Cartridges
9
7
79
8U
TRU
8
Th Removal, 4M HCl – 0.2 HF3
2
1
Sample Loading
Rinse: 3M HNO3
Cartridge Pre-treament: 3M HNO3
7 Elution, 4M HCl
8
9 Elution, 0.1 M Ammonium Bioxalate4 Cartridge Waste
5 Rinse: 3 M HNO3
6 Elution, 0.1M HCl-0.05M HF-0.03 M TiCl3
Laboratory standards, no counter ions present
Efficiency and Recovery of samples in Vacuum Box
Counter Ion Effects on Extraction Efficiency
Developing a novel extraction resin (Chris Klug)
Project Goal
Current Objective
Secondary Objective
Characterize a new extraction resin for trivalent actinide separations
Some commercially available resins use extractants from 1970s, 1960s, and earlier. Use molecules designed more recently for trivalent actinide separations in solvent extraction to maximize extraction properties.
N N
O O
R1
R2
R3
R4R5
Compare performance of our resins to commercially available resins and to solvent extraction systems
The novel resin will follow the “CHNO rule” – P or S can make incineration troublesome
Preliminary resins studied “TRU-like” resins – CMPO and TBP coated on a
polymer supportP
O O
N
CMPO
P
O
OOO
TBP
40
50
60
70
80
90
100
7001700270037004700
Wavenumber (cm^-1)
Tra
nsm
issi
on
(%
)
Comparison of commercial and homemade resins with CMPO and TBP
Extraction ChromatographyResin Development and Testing
Eu loading onto TRU-like resin
0
10
20
30
40
50
60
70
0 10 20 30 40 50 60
Fraction number
Mea
sure
d
Co
nce
ntr
atio
n
Static conditions were used to determine the resin capacity for Eu -as a homolog for Am
Eu breakthrough on a column was measured to determine the dynamic capacity
Eu and Am have been separated at unequal and equal concentrations
TRU Like resin Column Elution - Am/Eu Separation using 0.1 M HNO3
-0.2
0.2
0.6
1
1.4
1.8
0 50 100 150Fraction Number
pp
m E
u in
el
ute
d f
ract
ion
(pu
rple
d
iam
on
d)
-10
15
40
65
90
115
cpm
Am
-241
in
elu
ted
fra
ctio
n(p
ink
squ
are)
Column breakthrough (Eu)
Am/Eu Separation in HNO3
UNLV Deep BurnRepository Performance Tasks (You???)
Project Summary SNF Source Term Models
Based on LWR Fuel Cladding Failure UO2 Dissolution Kinetic
Release Model Particle Size Surface Area
Release to Near Field
TRISO Fuel Small oxide particles Intrinsic Transport Barrier
Goal: Develop Source Term Model for TRISO fuels
Predicting Repository PerformanceWork Planned at UNLV
TRISO Repository Behavior Actinide Sorption to Graphite
Determination of Equilibrium Sorption Evaluation of Sorption Kinetics
Degradation of Irradiated Graphite Evaluation of Degradation Rate for Irradiated Graphite Determination of Degradation Mechanisms
TRISO Fuel Performance Modeling Develop Source Term Model
Sorption-controlled release vs. degradation of graphite matrix?
Equilibrium Sorption vs. Desorption-kinetics controlled release?
Implement Model for Performance Assessment
Conclusions
Focusing on extraction chromatography protocols Simple, high selectivity, fast kinetics, lower waste
stream volume, and automatable Environmental sorption studies
Microbial activity should be considered for actinide transport
Sequential extraction studies will be conducted to investigate actinide sorption in soils
Develop more efficient methods for the isolation/separation of actinides in various matrices
Lessons from bone ash can be applied to cement and other construction materials
CONCLUSIONS
Basic Science Applications Develop new resins for actinide separations Develop methods suited for heavy element
chemistry Emergency Response
Developing an automatable radioanalytical protocol
Testing chromatography method on samples containing WG-Pu particulates
Forensics Capabilities Different interpretation of the same data Same samples, different analysis methods Isotopic information