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A NALYTICAL S EPARATIONS G ROUP Megan Bennett, Ashlee Crable, Sherry Faye, Narek Gharibyan, Julie Gostic, and Chris Klug Subgroup Leader: Ralf Sudowe.

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Presentation on theme: "A NALYTICAL S EPARATIONS G ROUP Megan Bennett, Ashlee Crable, Sherry Faye, Narek Gharibyan, Julie Gostic, and Chris Klug Subgroup Leader: Ralf Sudowe."— Presentation transcript:

1 A NALYTICAL S EPARATIONS G ROUP Megan Bennett, Ashlee Crable, Sherry Faye, Narek Gharibyan, Julie Gostic, and Chris Klug Subgroup Leader: Ralf Sudowe

2 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

3 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 ProjectileCompound Nucleus Fission Products Figure adapted from presentations by Dawn Shaughnessy and Ken Moody Hot Fusion or

4 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

5 Homolog Results Group IV Batch Results Using DGA resin Group V Batch Results Using DGA Resin

6 DGA Column Extractions Sample Loading: 1.0 M HNO 3 / 0.1 M HF, 1 mL Strip 1 (Pa): 0.4 M HNO 3 /0.2 M HF, 5 mL Strip 2 (Ta): 8M HNO 3 /0.2 M HF, 6 x 5 mL Strip 3: 0.1 M Ammonium Bioxalate, 5 mL Recovery >90% for all radionuclides. Strip 2

7 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 90 Sr using vacuum-assisted extraction chromatography (Sr·Spec resin cartridges) in the presence of Ca 2+

8 SEM image of bone ash

9 LSC results of spiked bone ash samples

10 Effect of bacteria on sorption of RN to soil (Sherry Faye) Sorption of 241 Am and 233 U 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.

11 Results 233 U Sorption in the Presence of Shewanella Tuff Surface Morphology using SEM

12 Measurement of neutron capture on Am- 241 (Narek Gharibyan) Objective Nuclear reactions Investigation 241 Am 242 Cm IT 242 Am β-β- (n,γ) 141 y h d Separation of curium from americium for neutron capture cross section and isomeric ratio measurements ( 242m+g Am from 241 Am) Am/Cm separation methods with extraction chromatography resins from Eichrom that would not require changing Am (III) oxidation state.

13 TEVA resin results Effects of various nitrates (LiNO 3, KNO 3, NaNO 3, Al(NO 3 ) 3, Mg(NO 3 ) 2, Ca(NO 3 ) 2 ) on Am/Cm separation: N + NO 3 - R CH 3 R R R = C 8 H 17 and C 10 H 21 Trialkyl, methylammonium nitrate K Li(NO 3 ) 3

14 TRU resin results Acid dependency (HNO 3, HCl) on Am/Cm separation from various resins:

15 Automated Rapid Separations (Julie Gostic)

16 Laboratory Samples (3M HNO 3 -1 M Al(NO 3 ) 3, 1.5M Sulfamic and Ascorbic Acids, 3.5M NaNO 2 ) Discard Eluent Am TRU TEVA Discard Eluent 5 6 Pu 6 5 TEVA Disconnect Cartridges U TRU 8 Th Removal, 4M HCl – 0.2 HF Sample Loading Rinse: 3M HNO 3 Cartridge Pre-treament: 3M HNO 3 7 Elution, 4M HCl 8 9 Elution, 0.1 M Ammonium Bioxalate 4 Cartridge Waste 5 Rinse: 3 M HNO 3 6 Elution, 0.1M HCl-0.05M HF-0.03 M TiCl 3

17 Laboratory standards, no counter ions present Efficiency and Recovery of samples in Vacuum Box

18 Counter Ion Effects on Extraction Efficiency

19 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. 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

20 Preliminary resins studied TRU-like resins – CMPO and TBP coated on a polymer support Comparison of commercial and homemade resins with CMPO and TBP

21 Extraction Chromatography Resin Development and Testing 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 Column breakthrough (Eu) Am/Eu Separation in HNO 3

22 UNLV Deep Burn Repository Performance Tasks (You???) Project Summary SNF Source Term Models Based on LWR Fuel Cladding Failure UO 2 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

23 Predicting Repository Performance Work 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

24 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

25 C ONCLUSIONS 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


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