p. 1 DOE Office of Nuclear Energy Nuclear Fuels Resources Workshop Plenary Closing Session October 14, Potential scientific impactPotential technological impact Summary of research directionScience and Technology challenges Panel Title: Basic science to understand how amidoxime works New ligand design principle for uranyl ions A guide to improve performances New stripping strategy What is the structure of coordination sites? What basic thermodynamic and kinetic properties of amidoxime complexation processes? Synthesis of model compounds Spectroscopic and structural characterization Thermodynamic & kinetic investigation

p. 2 DOE Office of Nuclear Energy Nuclear Fuels Resources Workshop Plenary Closing Session October 14, Potential scientific impactPotential technological impact Summary of research directionScientific challenges Extraction: Uranyl binding mechanism in amidoxime adsorbents? Synthesis of simple analogs Structural studies to characterize coordination modes Solution studies to characterize binding affinity, selectivity and kinetics of binding. Model potential species using electronic structure calculations Uranium complexation in AO polymers is not understood. What is the main uranyl binding motif in these materials? Fundamental understand of why these polymers work. Provide a basis to design improved adsorbents based on the amidoxime functional group. Improved adsorbent performance will result in significant cost reduction years

p. 3 DOE Office of Nuclear Energy Nuclear Fuels Resources Workshop Plenary Closing Session October 14, Potential scientific impactPotential technological impact Summary of research directionScience and Technology challenges Panel Title: Physical Oceanography and Related None Identify locations (appropriate currents and temperature; plus deal with environmental and regulation issues) Refine technology (mooring design, process optimization) Carry out tests to optimize system design for present chemistry Document the intersection of appropriate temperatures, appropriate currents and legally permissible sites

p. 4 DOE Office of Nuclear Energy Nuclear Fuels Resources Workshop Plenary Closing Session October 14, Potential scientific impactPotential technological impact Summary of research directionScientific challenges Resource Extraction: Sorbent Enhancement New composite materials built from nanoporous components to enhance extractant transport, diffusion, and binding Can stable polymeric or inorganic supports with significantly enhanced surface areas and mass transport properties be developed to increase both capacity and efficiency of uranyl adsorption under seawater conditions? More efficient extraction Higher binding capacity New material synthesis and processing techniques Increase system durability Reduce transportation and processing costs Reduce overall nuclear resource costs

p. 5 DOE Office of Nuclear Energy Nuclear Fuels Resources Workshop Plenary Closing Session October 14, Potential scientific impactPotential technological impact Summary of research directionScientific challenges Extraction: Enhanced ligands for UO 2 2+ sequestration Identify donor groups (phosphate, amide, imine, hydroxamate, etc.) Computer-aided design of candidate ligand structures that can be incorporated in adsorbents Synthesis of compounds Structural studies to characterize coordination modes Solution studies to characterize binding affinity, selectivity and kinetics of binding. Develop improved ligands for removal of uranyl cation from seawater: increased affinity and selectivity rapid kinetics stable in marine environment synthetically accessible and cheap easily stripped How ligand structure impacts uranyl binding How variation in donor groups influences uranyl binding – cooperativity effects Improved adsorbent performance will result in significant cost reduction years

p. 6 DOE Office of Nuclear Energy Nuclear Fuels Resources Workshop Plenary Closing Session October 14, Potential scientific impactPotential technological impact Summary of research directionScientific challenges Resource Estimation and Exploration: Uranium complexation thermodynamics and kinetics To study fundamental uranium complexation experimentally and to model these processes computationally What are the unique thermodynamic and kinetic properties of polymer adsorbents associated with uranyl sorption processes? Better understanding of uranium coordination chemistry Better methodologies for computing metal-ligand coordination thermodynamics Development of chelators with better binding characteristics More efficient uranium extraction

p. 7 DOE Office of Nuclear Energy Nuclear Fuels Resources Workshop Plenary Closing Session October 14, Potential scientific impactPotential technological impact Summary of research directionScientific challenges Develop New functional group incorporation, grafting, and attachment chemistries Are there new synthetic techniques for incorporation of a high density of binding sites into adsorbent supports? Higher binding capacity More efficient extraction New surface chemistry Reduce transportation and processing costs Reduce overall uranium extraction costs Resource Extraction: Increasing functional Group Density

p. 8 DOE Office of Nuclear Energy Nuclear Fuels Resources Workshop Plenary Closing Session October 14, Potential scientific impactPotential technological impact Summary of research directionScientific challenges Resource Extraction: Leverage of nanotechnology Develop new nanostructured materials as novel sorbents for selective uranium binding Can recent breakthroughs in nanotechnology be used to make advanced adsorbents for recovery of uranium from seawater? Enhanced extractant transport and diffusion New nanoscience and nanotechnology Increase system durability Reduce transportation costs Reduce overall nuclear resource costs

p. 9 DOE Office of Nuclear Energy Nuclear Fuels Resources Workshop Plenary Closing Session October 14, Potential scientific impactPotential technological impact Summary of research directionScience and Technology challenges Panel Title: Photopolymerization/Photografting Straightforward grafting/polymerization methods using readily available, low cost UV light sources, materials, and synthetic techniques. Screen potential ligand technology using benchtop equipment. High capital cost and availability of high energy radiation. Can reasonable degree of grafting be achieved using lower energy radiation? Radical decay between irradiation and grafting. This approach opens door for widespread research in uranium absorption. Wide range of chemistries (e.g. thiol ‘click’, living radical) available. Primarily surface modification which could lead to more efficient adsorption and preserved fiber integrity, durability, and longevity. This approach opens door for widespread research in uranium absorption. Simultaneous radical generation and grafting. Initial evaluation of effectiveness within 3 years.

p. 10 DOE Office of Nuclear Energy Nuclear Fuels Resources Workshop Plenary Closing Session October 14, Potential scientific impactPotential technological impact Summary of research directionScientific challenges Resource Extraction: Enhanced uranium stripping To better understand uranium coordination chemistry to identify best stripping methods Is any better and cleaner stripping process or recycling strategy to efficiently recycle adsorbents? New knowledge about uranium chemistry Improved product separation and recovery techniques Less secondary wastes Selective stripping for better uranium purity and for recovery of other valuable co- products

p. 11 DOE Office of Nuclear Energy Nuclear Fuels Resources Workshop Plenary Closing Session October 14, Potential scientific impactPotential technological impact Summary of research directionScientific challenges Extraction: Recognition of the [UO 2 (CO 3 ) 3 ] 2- dianion Evaluate speciation as a function of concentration up to the lower limit of the technique and then extrapolate to the seawater concentration. De novo structure-based design and high throughput screening to identify host structures that complement the targeted species. Speciation of uranyl ion at seawater concentrations Achieving significant binding affinity for an anionic metal complex Better understanding of uranyl speciation in seawater Development of characterization techniques applicable to extremely low concentrations and complex media. Demonstrate the feasibility of outer-sphere host- guest complexation Significant improvement of selectivity for uranyl over competing transition metals years

p. 12 DOE Office of Nuclear Energy Nuclear Fuels Resources Workshop Plenary Closing Session October 14, Potential scientific impactPotential technological impact Summary of research directionScience and Technology challenges Panel Title: Resource Extraction Impact of biofouling on extraction technologies Need for actual field testing, or raw seawater studies in controlled tanks New antifouling strategies Characterization of microbial interaction with novel material types May force selection or rejection of some materials System design concerns to ameliorate fouling 3-5 years for early impact Determine potential impact biofouling may have on extraction technologies: Interference of molecular foulants (peptides, polysaccharides, nucleic acids) on nanomaterials Impact of fouling coatings on U-recovery process (calcite or silica oozes) Potential for organisms to degrade sorbants

p. 13 DOE Office of Nuclear Energy Nuclear Fuels Resources Workshop Plenary Closing Session October 14, Potential scientific impactPotential technological impact Summary of research directionScience and Technology challenges Panel Title: Resource Extraction Site Selection and Permitting for Sorbent fields Lab tank testing of U-saturated sorbant materials with model organisms. Test uptake potential, leaching, grazing Industry cannot begin to write an environmental impact statement without conducting basic research to understand issues such as: Potential toxicity and leaching of sorbant chem Potential entry of concentrated U into food web Durability of material under field conditions Model and test the impact of design local ocean current, benthic ecology, marine mammals, fish May result in the selection or rejection of certain chemistries. Empirical testing will provide valuable data about bioaccumulation of U in primary producers through higher order predators Impacts system design and location considerations What’s the timescale in which that impact may be felt?

p. 14 DOE Office of Nuclear Energy Nuclear Fuels Resources Workshop Plenary Closing Session October 14, Potential scientific impactPotential technological impact Summary of research directionScience and Technology challenges Panel Title: Resource Extraction Permitting DOE policy maker level action Consider site selection issues for marine hydrokinetic power Will impact ability to conduct field tests and to engage industry– no industry investment likely if no clear path to approval Will impact site selection and feasibility studies– may never be able to leave the laboratory Minimum of 3-5 years Policy concern: begin dialogue to determine who has oversight for site selection and environmental impact statements (EIS) State, EPA, NOAA, Coast Guard, Navy, DOE, etc

p. 15 DOE Office of Nuclear Energy Nuclear Fuels Resources Workshop Plenary Closing Session October 14, Potential scientific impactPotential technological impact Summary of research directionScience and Technology challenges Panel Title: Resource Extraction Cost analysis of tying U-extraction to desalination Full analysis of water technologies, need, new and existing plant expansion, implementation forecasts Model extraction potential for various desal technologies (RO, MSF, emerging methods) Model flow dynamics (shorter residence time on materials Less environmental impact and lower permitting barriers Use of enriched brines at elevated temperatures may improve extraction efficiency for some ligand materials Fewer complications: no field deployment and recovery Value added for another industry Desalination will grow as an industry– Water wars in the west coast are worsening, demand is growing, and CA cannot continue to drain the Colorado River. Florida’s aquifers are not meeting demand. Pumping costs are not a factor for U extraction- the water is the primary commodity and will drive the creation of the pump facility. The waste flow is an untapped byproduct concentrated brine at an elevated temperature. Need to forecast the growth of desal in US and model extraction potential from various desal technologies (brine types). U extraction (and other minerals) becomes added value to desal facility

p. 16 DOE Office of Nuclear Energy Nuclear Fuels Resources Workshop Plenary Closing Session October 14, Potential scientific impactPotential technological impact Summary of research directionScience and Technology challenges Panel Title: Resource Extraction Biogenic ligands for U-extraction Phage display, clone and subclone active sites from chelators, metaloproteins, reductases Molecular modeling and synthetic biological design Clone and mass-express ligands Discover/engineer new ligands Develop screening processes Biomolecular engineering and cloning Scaled production and linkage chemistry Low cost, green fabrication New classes of ligands Minimum of 3-5 years Explore the use of biogenic ligands (e.g. metalloproteins, U-reductase, peptide aptamers) for U extraction; these offer the potential for lower cost “green” fabrication and easier recovery of the extracted U (partial denaturation using mild heat, salt wash, or pH change) Explore efficiency, stability, and cost Compare with synthetic ligands for same parameters Explore best substrates and attachment methods