Seaborg Institutes: Emerging Topics in Actinide Materials and Science: Separations/Forensics
Sponsored by: TMS Structural Materials Division, TMS: Nuclear Materials Committee
Program Organizers: J. Rory Kennedy, Idaho National Laboratory; Taylor Jacobs, Helion Energy; Krzysztof Gofryk, Idaho National Laboratory; Assel Aitkaliyeva, University of Florida; Don Wood, Idaho National Laboratory
Monday 8:30 AM
March 20, 2023
Room: 28A
Location: SDCC
Session Chair: Rory Kennedy, INL; Don Wood, Idaho National Laboratory
8:30 AM Introductory Comments
8:35 AM Invited
Next Steps for Actinide Separations & Reprocessing: Jenifer Shafer1; 1Colorado School of Mines
The most developed reprocessing technology in existence is PUREX. PUREX was developed nearly 70 years ago as a part of U.S. efforts during the Cold War. Actinide separations needs were different then and received robust government support. Consequentially, the production of pure plutonium streams was considered technologically important and the costs incurred from large footprint dissolution processes and waste treatment practices was considered irrelevant. While the PUREX process has been converted to support commercial nuclear power efforts in various countries, the technology is expensive and requires government support to develop a commercially viable fuel feedstock. While the separations step individually represents a relatively small cost compared to the broader facility, all headend steps and backend waste treatments support the separation and these drive significant cost. This presentation will consider technologies that can both 1) limit the production of pure plutonium streams and 2) decrease the cost of reprocessing technologies.
9:05 AM Invited
Actinide Electrochemistry at Metal Oxide Electrodes: Christopher Dares1; Jeffrey McLachlan1; Xiangyang Hou1; Evan Jones1; Gabriela Ortega1; Travis Grimes2; 1Florida International University; 2Idaho National Laboratory
Precise oxidation state control is imperative to nuclear fuel recycling. Actinides of relevance to nuclear fuel reprocessing (U, Np, Pu, and Am) exist in oxidation states from +6 to +3. In aqueous acidic solutions, the hexa- and pentavalent states they exist as actinyl cations. Most solvent extraction methods developed to separate these elements from fission products rely on differences in bonding properties. The stronger Lewis acids (hexavalent and tetravalent) can thus be separated from the weaker. During extraction, oxidation state stability changes with the change in coordination and solvent environment often resulting in unfavorable oxidation state changes like the generation of a pentavalent species. We herein will present work on the development and use of functionalized metal oxide electrodes and evaluate their electrochemical properties with uranium and other actinides. This includes surface functionalization with ligands to favor high or low oxidation states and the resultant differences in uranium electrochemistry.
9:35 AM
Methodology and Density of PuCl3-NaCl Mixtures: Michael Woods1; Toni Karlsson1; Ruchi Gakhar1; 1Idaho National Laboratory
The development of molten salt reactors and their associated components demands reliable and accurate thermophysical property data for design and validation. A candidate fuel salt, PuCl3-NaCl (36 mol% PuCl3) has been synthesized and studied at the Idaho National Laboratory. This study has determined the density of PuCl3-NaCl at multiple compositions and temperatures, providing data for validation of modeling efforts and making improvements on the buoyancy method for density measurements of actinide-bearing molten salts.
9:55 AM
Melting Temperature Method for Determining the Concentration of Pu-metal in PuCl3 Salt: Toni Karlsson1; Cynthia Adkins1; 1Idaho National Laboratory
A sodium-chloride plutonium-trichloride binary salt system has been fabricated for thermophysical property investigations with the goal of informing molten salt reactor fuel development. A simultaneous thermal analyzer (STA) was deployed to investigate purity of the plutonium-trichloride feedstock utilized during binary salt fabrication. Subsequently, the STA was used to develop a phase diagram for the sodium-chloride plutonium-trichloride salt. Six different molar ratio salt samples were measured to develop the phase diagram. The phase diagram results were compared with the limited available literature values for this binary salt system.
10:15 AM Break
10:35 AM Invited
Actinide Science for Post Detonation Nuclear Forensic Analyses: Mathew Snow1; David Chichester1; James Johnson1; Tommy Holschuh1; Jessica Meiers1; Jacob Brookhart1; 1Idaho National Laboratory
Full abstract is currently under review and will be available shortly
11:05 AM Invited
Local Structure and Distribution of Impurities in Plutonium Materials for Nuclear Forensics: Sarah Hickam1; Kasey Hanson1; Harry Jang1; Arjen van Veelen1; Daniel Olive1; Nicholas Edwards2; Alison Pugmire1; 1Los Alamos National Laboratory; 2SLAC National Accelerator Laboratory
Synchrotron X-ray absorption spectroscopy (XAS) is an established method for acquiring element-specific local structure information from materials. Combining this method with x-ray fluorescence (XRF) elemental mapping provides the ability to quickly locate particles or “hot spots” of interest with up to 1 μm resolution and then obtain local structure information from individual points. One potential application of this technique is nuclear forensics, where there is a need to identify particles and then rapidly and nondestructively acquire information. Our work uses the combination of XRF and XAS to identify potential forensic signatures of PuO2 particles and bulk Pu metal samples. One focus is the investigation of impurities in these materials, which is made possible by the low detection limits (ppm) and element-specific nature of XAS. Our observations of differences in impurity local structure and distribution with different Pu metal oxidation conditions demonstrate the potential application of this technique for nuclear forensics.