2013 abstract book ASNFC-Shanghai

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Shanghai, Nuclear fuel cycle Asian Symposium
Reprocessing of Spent Nuclear Fuel
Radionuclides, Technetium, Actinides, Transuranium elements

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2013 abstract book ASNFC-Shanghai

  1. 1. Contents Plenary Lectures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1 Some Hot Issues on Nuclear Energy Chemistry in China . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 . Present Status of Nuclear in Japan after the Accident of Fukushima Daiichi . . . . . . . . . . . . . . 3 Session 1: General Issues on Nuclear Energy and Fuel Cycle . . . . . . . . . . . . . . . . . 5 . 1.1 Envision of World Nuclear Energy / Fuel Cycle Development and China's Action . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 . 1.2 The Role of Advanced Reprocessing Technology on 3S (Safety, Security, and Safeguards) in Nuclear Fuel Cycle and Radioactive Waste management . . . . . . . . . . . . 7 . 1.3 Flexible Fuel Cycle Initiative to Cope with the Uncertainties after Fukushima Daiichi NPP Accident . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8 1.4 Advanced Fuel Cycle : Status and Technology Development at KAERI . . . . . . . . . . . . . . 9 . 1.5 The Nuclear Education and Training Program at University of California Irvine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10 Session 2: Basic Chemistry of Actinides and Fission Products . . . . . . . . . . . . . . .11 2.1 Utilization of Technetium and Actinide Compound Synthesis and Coordination Chemistry for the Nuclear Fuel Cycle: Exploring Separations, Fuels, and Waste Forms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 . 2.2 Heptavalent State of Transuranium Elements, Technetium and the Other Elements of the Periodic Table . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 2.3 DFT Study on a Trivalent Uranium Complex Promoted Functionalization of Carbon Dioxide and Carbon Disulfide . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 . 2.4 Using Phosphonates to Probe Structural Differences Between the Transuranium Elements and Their Proposed Surrogates . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 . 2.5 From Thorium to Curium: Unprecedented Structures and Properties in Actinide Borates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .18 2.6 Diamides of Dipicolinic Acid in Complexation and Separation of Selected Metals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .20 2.7 Recovery of Uranium by Adsorbents with Amidoxime and Carboxyl Groups: A Density Functional Study . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 2.8 Theoretical Studies on the Electronic Structure and Chemical Bonding of UX5–(X = F, Cl) Complexes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .23 . 2.9 First-principles Calculation of Intrinsic and Defective Properties of UO2 and ThO2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 2.10 Modeling the Autocatalytic Reaction between TcO4- and MMH in HNO3 Solution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 2.11 Fluorescent BINOL-Based Sensor for Thorium Recognition and a Density Functional Theory Investigatio . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 .
  2. 2. 2.12 Exceptional Selectivity for Actinides by N,N’-Diethyl-N,N’-Ditolyl-2,9Diamide-1,10-Phenanthroline Ligand: A Combined Hard-Soft Atoms Principle# . . . . . . . . .28 2.13 The Studies on Optimization of the Separation Method of Am and Cm . . . . . . . . . . . . .29 2.14 Burn-up Calculation of Plutonium in Fusion-fission Hybrid Reactor . . . . . . . . . . . . . . . .30 2.15 [UO2(NO3)4]2- Complex in Ionic Liquids Investigated by Optical Spectroscopic and Electrochemical Studies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 2.16 Complexation of Uranyl by Neutral Bidentate Phosphonate Ligands in Ionic Liquids . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33 . Session 3: Waste Management . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .35 3.1 Sorption of Uranium and Rhenium in the Presence of Fulvic Acids . . . . . . . . . . . . . . . . .36 3.2 Oxalic Acid Effect on the Diffusion of Se(IV) and Re(VII) in Bentonite . . . . . . . . . . . . . . .37 3.3 Migration of Actinides and fission products in Environments . . . . . . . . . . . . . . . . . . . . . .39 3.4 Development of Negative Ce Anomalies in Biogenic Mn Oxide: the Role of Microorganism on REE Mobility during the Bio-oxidation of Mn2+ . . . . . . . . . . . . . . . . . . . . .41 3.5 New Biotechnology Methods for Radioactive Wastes Treatment . . . . . . . . . . . . . . . . . . . 42 3.6 Removal of Radioactive Cesium from Soil and Sewage Sludge Contaminated by Fukushima Daiichi NPP Accident . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .43 3.7 Synthesis of Multifunctional Silica-based Adsorbents and Their Application in Decontamination of Radioactive Contaminated Wastewater . . . . . . . . . . . . . . . . . . . . . . . 45 . 3.8 Remove uranium and Fluorine from Wastewater . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .46 3.9 Irradiation Stability of the Tributyl Phosphate Solvent Extraction System . . . . . . . . . . . . 48 . 3.10 U(VI) Sorption on Silica in the Presence of Short Chain Mono-carboxylic Acids . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .50 3.11 Effect of Some Ions on the Sorption of Th(IV) to K-feldspar . . . . . . . . . . . . . . . . . . . . . 51 . 3.12 Uranyl Ions Sorption to TiO2 and Interaction with Sorbed FA: Experiments and Modeling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .52 3.13 Thermal Decomposition Behavior of Nitrate Solution Containing Di-nbutylephosphate in Vitrification Process . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .53 3.14 Study on the Synthesis of AMP Loaded Silica and Its Adsorption Behavior for Cs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .54 3.15 Selective Adsorption and Stable Solidification of Sr by Potassium Titanates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .56 3.16 Adsorption and Stable Solidification of Cesium by Insoluble Ferrocyanide Loaded Porous Silica Gels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57 . 3.17 Separation of Nuclides by Different Types of Zeolites in the Presence of Boric Acid . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .58 Session 4: Transmutation, Resources and Materials Utilization, etc. . . . . . . . . . . .59 4.1 Hydriding Properties of Uranium Alloys - Their Meaning for Nuclear Fuel Cycle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60 4.2 Microstructural Study of As-Cast U-Rich U- Zr Alloys . . . . . . . . . . . . . . . . . . . . . . . . . . . 61 .
  3. 3. 4.3 Production of Standard Particles and Their Application in Particle Analysis for Nuclear Safeguards . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63 4.4 Après ORIENT, A New P&T Challenge to Transmute Radioactive Wastes into Resources . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64 . 4.5 The Numerical Analysis about the Creation of Strategic Important Elements by Nuclear Transmutation Processes of Fission Products . . . . . . . . . . . . . . . . . . .66 Session 5: Hydro-Separation Technologies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68 . 5.1 Current Status of Reprocessing Process using Pyridine Resin in Hydrochloric Acid Solution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69 . 5.2 Studies on the Advanced Hybrid Reprocessing System “FluoMato” Process . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71 5.3 R&D Efforts Using Novel Extractants for the Development of ‘Green’ Separation Technologies Relevant in the Back-End of Nuclear Fuel Cycle . . . . . . . . . . . . . .73 5.4 Preparation of High Purity Thorium by Centrifugal Extraction . . . . . . . . . . . . . . . . . . . . . 75 . 5.5 Development of Selective Separation Method for Nuclear Rare Metals Using Highly Functional Xerogel Microcapsules . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76 . 5.6 Novel Pillar[5]arene-Based Phosphine Oxides as Extractants for the Segregation of f-Block Elements from Acidic Media in Biphasic Systems . . . . . . . . . . . . . . .77 5.7 Synthesis and Adsorptivity of Acryloylmorpholine Resin for Selective Separation of U(VI) in Nitric Acid Media . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .79 5.8 Adsorption Behavior of Am(III) and Ln(III) from Nitric Acid Solution onto isoHexyl- BTP/SiO2 -P Adsorbent. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .80 5.9 Preparation of Anion Exchanger by Pre-irradiation Grafting Method and Its Adsorptive Removal of Rhenium as an Analogue of Radioactive Technetium . . . . . . . . . . .81 5.10 Adsorption of Th4+ from Aqueous Solution onto Poly(N,Ndiethylacrylamid e-co-acrylic acid) Microgels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .82 5.11 Recovery of 233U from Irradiated Thorium Oxide Using 5% TBP as Extractant . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .85 5.12 Synthesis and Characterization of UO2 2+-ion Imprinted Polymer for Separation and Preconcentration of Trace Uranyl Ions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86 . 5.13 Solid Phase Extraction Using N-doped Carbonaceous Covalent Organic Frameworks for Treatment of Uranium (VI) Ions from Water Solutions . . . . . . . . . . . . . . . . .88 5.14 Extraction of Thorium(IV), Uranium(VI) and Rare Earths with NTAamide . . . . . . . . . . . 90 . 5.15 Adsorption and Separation Characteristics of Thorium from Nitric Acid Solution Using Silica-Based Anion Exchange Resins . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91 . 5.16 Adsorption and Elution of Rhenium (VII) with a Porous Silica-based Anion Exchanger AR-01 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .93 5.17 Study on the Properties of isoBu-BTP/SiO2-P Adsorbent in the Separation of Minor Actinides . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94 5.18 Removal of Th4+ Ions from Aqueous Solutions by Graphene Oxide . . . . . . . . . . . . . . .95
  4. 4. 5.19 Influence of γ-irradiation on the isoBu-BTP/[C2mim][NTf2] Extracting System during Dy(III) Extraction . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . 96 5.20 Ethanolamine-isocyanate Modified Graphite Oxide for Selective Solid-phase Extraction of Uranium .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98 . 5.21 Separation Behavior of Rare Metals by Functional Xerogels Impregnated with MIDOA Extractant . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100 Session 6: Pyro-Separation Technologies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .101 6.1 Recent Study on Pyrochemical Treatment of Spent Nitride Fuels in JAEA . . . . . . . . . . 102 . 6.2 Thorium based Molten Salt Fuel Cycle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103 6.3 The Study on the Solubility of Rare Earth Oxides in a New Molten Salts LiCl-NaCl-MgCl2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 104 6.4 Separation of SmCl3 and DyCl3 by Galvanostatic Electrolysis in LiCl-KCl Melts at Magnesium Electrodes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .106 6.5 Electrochemical Extraction of Holmium in LiCl-KCl-HoCl3 Melts on a Nickel Electrode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 108 . 6.6 Electrochemical Behaviors of REs in FLINAK Eutectics . . . . . . . . . . . . . . . . . . . . . . . . 110 . 6.7 Electrochemical Behavior of Cerium and Electrodeposition of Al–Li–Ce Alloys from Molten Chlorides . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 111 . 6.8 Electrochemical Extraction of Thulium in LiCl–KCl Melt Containing TmCl3 at Liquid Zn Electrodes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .112 6.9 Electrochemical Behavior of Erbium and Aluminum in the LiCl-KCl Eutectic . . . . . . . . .114 6.10 Electrochemical Extraction of Samarium from LiCl-KCl Melt by forming Sm-Zn Alloys . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 116 . 6.11 Molecular Dynamics Simulation of Molten LiF-ThF4 Salt Systems . . . . . . . . . . . . . . 117 Session 7: Innovative Materials and Separation . . . . . . . . . . . . . . . . . . . . . . . . . . .118 7.1 Study on Proton Beam Irradiation of Ionic Liquid . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 119 7.2 Surface Modification of Carbon Nanomaterials and their Application in Radionuclide Pollution Cleanup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 121 . 7.3 Extraction Uranium from Aqueous Solution with Malonamide into Ionic Liquid . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 122 . 7.4 Extraction of Uranium(VI) and Thorium(IV) Ions from the Aqueous Phase into an Ionic Liquid by 4-oxaheptanediamides . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .125 7.5 Radiation Effect on EuIII Extraction Ability of BTPhen ILs System . . . . . . . . . . . . . . . 127 7.6 Separation of Uranyl Species Using Task-specific Ionic Liquid, [Hbet][Tf2N] . . . . . . . . 129 7.7 Dissolution of UO2 in the System of [Imim][FeCl4]-DMSO . . . . . . . . . . . . . . . . . . . . . . 130 7.8 Influence of Solvent Structural Variations on the isoBu-BTP [Cnmim][ NTf2] Extracting System during Eu(III)/Dy(III) Extraction . . . . . . . . . . . . . . . . . . . . . . . . . . .132 7.9 Extraction of Several Rare-earth Metal Ions Using isoBu-BTP[C2mim][ NTf2] System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 134 .
  5. 5. 7.10 Electrodeposition of Rh(III) and Pd(II) from 1-Ethyl-3-Methylimidazolium Trifluoroacetate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 136 7.11 Adsorption of Thorium on Magnetic Multi-walled Carbon Nanotube . . . . . . . . . . . . . . 138 . 7.12 A Catechol-like Phenolic Ligand-functionalized Hydrothermal Carbon : One-pot Synthesis, Characterization and Sorption Behavior towards Uranium . . . . . . . . . .139 7.13 A Simple Approach to Highly Efficient Uranium Selective Sorbent : Preparation and Performance of a Novel Amidoxime-functionalized Hydrothermal Carbon . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .141 7.14 Amidoxime-Grafted Multiwalled Carbon Nanotubes by Plasma and its Application in the Removal of Uranium . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 143 . 7.15 Amino Functionalized MIL-101 Metal–Organic Frameworks (MOFs) for U(VI) Capture . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .144 7.16 A Novel Functionalized 2-D COF Materials : Synthesis and Application as Selective Solid-phase Extractant in Separation of Uranium . . . . . . . . . . . . . . . . . . . . . . . . .145 7.17 Comparation of Ce(IV) Stripping Rate from TBP and DBP . . . . . . . . . . . . . . . . . . . . . 147 . 7.18 Impact of Low Molecular Weight Organic Acids on Uranium Uptake and Distribution in a Variants of Mustard (Brassica juncea var.tumida) . . . . . . . . . . . . . . . . . . . 148 . 7.19 Sorption of Selenium(IV) on Modified Bentonit . .. . . . . . . . . . . . . . . . . . . . . . . . . . 149 7.20 Pyrohydrolysis of Fluorides from Thorium-based Molten Salt Reactor . . . . . . . . . . .151 7.21 Comparative Study on Sorption of Eu(III) to Two Kinds of Mica Muscovite and Phlogopite . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 152 . 7.22 Sorption of Np(V) onto Na-bentonite : Effect of equilibrium time, pH, ionic strength and temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .154 7.23 Application and Evaluation of Radioisotope in Tracer Technique. . . . . . . . . . . . . . . . .155 7.24 Extraction of U(VI) and Th(IV) from Aqueous Solution into Ionic Liquid or N-pentanol Using Methylimidazole Derivatives as Extractants . . . . . . . . . . . . . . . . . . . . . . 156 .
  6. 6. Plenary Lectures 1
  7. 7. Some Hot Issues on Nuclear Energy Chemistry in China Zhifang Chai Nuclear Energy Chemistry Group, Key Laboratory of Nuclear Analytical Techniques Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, China E-mail: chaizf@ihep.ac.cn Nuclear energy future in China will be still bright following the Fukushima Accident. The reason is straightforward: (1) Nuclear energy, per se, is a safe and clean energy source; (2) China can not survive as a productive economy without nuclear energy, and in the meantime it needs to control the emission of the green house gas. Therefore, there is a strong impetus to develop nuclear energy in China, which is now experiencing a renaissance. In this talk, the recent achievements in nuclear energy chemistry of China are selectively highlighted, with emphasis on the extraction of uranium from seawater, front-end chemistry, actinide coordinated chemistry associated with nuclear fuel fabrication, actinide solution chemistry and nuclear fuel reprocessing. Another key issue is how to apply nano-materials and nano technology in nuclear energy chemistry. Some positive measures for promotion of the nuclear energy chemistry in China will be addressed, and future perspectives will be briefly outlined as well. Nuclear energy chemistry in China needs new thoughts, new methods and new materials; needs multidisciplinary research; and, particularly, needs bright young scientists. Acknowledgement This work was supported by Natural Science Foundation of China (Grants 91026007, 91226201 and 11275219) and the "Strategic Priority Research Program" of the Chinese Academy of Sciences (Grants XDA030104). References 1. WQ Shi, YL Zhao, ZF Chai. Radiochim Acta. 2012, 100: 529. 2
  8. 8. Present status of nuclear in Japan after the accident of Fukushima Daiichi Toshio Wakabayashi Tohoku University, Japan The great earthquake of magnitude 9 and the later tsunami on March 11, 2011 gave very serious damages to the East Japan area. About nuclear power plants of the East Japan, 11 plants were operated before the earthquake and all the plants were automatically safely stopped at the time of the earthquake. However, as for Fukushima Daiichi Nuclear Power Plant, a large quantity of radioactive materials was released by meltdown of the core and the hydrogen explosions of reactor buildings after tsunami. Many inhabitants within the area of 30km of Fukushima Daiichi nuclear power plants are now evacuating. Present status of nuclear in Japan after the accident of Fukushima Daiichi is introduced in this paper. The status of Fukushima Daiichi nuclear power station and the status of the long-and-mid term roadmap towards the decommissioning are shown as follows. Cold Shutdown Condition is maintained at Unit 1-3. Measures to complement status monitoring are being implemented. The RPV bottom temperature and the PCV gaseous phase temperatures at Units 1-3 were approx.30-50 degrees (as of October 19) and fulfill the requirement (100 degrees or less). The highly radioactive water accumulated in the building basement is treated to be used for reactor cooling. The contaminated water generated in this process treated and stored. Preparation for fuel removal from the spent fuel pool is in progress. Debris removal from the upper part of Units 3-4 Reactor Building is in progress to prepare for fuel removal from the spent fuel pool. The Nuclear Regulation Authority(NRA) was established in September 2012 to absorb and learn the lessons of the Fukushima Daiichi nuclear accident of March 11, 2011. The fundamental mission of the NRA is to protect the general public and the environment through rigorous and reliable regulations of nuclear activities. The new regulatory requirements were decided taking into account the lessons-learnt from the accident at Fukushima Daiichi Nuclear power plants. Main requirements are shown as follows. (1) Measures to prevent core damage(postulate multiple failures) (2) Measures to prevent containment vessel failure (3) Measures to suppress radioactive materials dispersion (4) Consideration of internal flooding (5) Consideration of natural phenomena in addition to earthquakes and tsunamis--volcanic eruptions, tornadoes and forest fires (6) Response to intentional aircraft crashes Concerning the reprocessing plant of the Japan Nuclear Fuel Limited(JNFL) in Rokkasho, the completion timing of the reprocessing plant is being examined based on the evaluation status of the 3
  9. 9. nuclear power station and trend of the new regulatory requirements on cycle facilities. The new process will be notified as soon as it has been organized. JNFL has been constructing the Vitrification Technology Development Facility, which is the base of research and development, within the reprocessing site in order to further improve vitrification technology. The Japan Atomic Energy Agency(JAEA) will be reformed to focus on the Fukushima Daiichi nuclear accident support, the research for enhancement of nuclear safety, the basic nuclear research, and R&D for nuclear fuel cycle including Monju development. 4
  10. 10. Session 1: General Issues on Nuclear Energy and Fuel Cycle 5
  11. 11. ENVISION OF WORLD NUCLEAR ENERGY /FUEL CYCLE DEVELOPMENT AND CHINA’s ACTION GU Zhongmao China Institute of Atomic Energy / Shanghai Jiaotong University The worldwide nuclear energy development including China after Fukushima nuclear accident is briefly viewed. The international general trend of fuel cycle for sustainable development is envisioned, and China’s efforts to develop advanced nuclear fuel cycle are described. Data shows that the global nuclear energy development has stepped out of the shadow of Fukushima accident. Advanced nuclear fuel cycle, or Fast reactor cycle, is a sustainable way of nuclear fission energy. Such understanding is becoming the consensus of the world nuclear community. China has a big nuclear energy program and must establish an advanced nuclear fuel cycle system, which is geared to the international trends. 6
  12. 12. The Role of Advanced Reprocessing Technology on 3S (Safety, Security, and Safeguards) in Nuclear Fuel Cycle and Radioactive Waste management Jor-Shan CHOI 1 1 UC Berkeley Nuclear Research Center, University of California at Berkeley, CA, USA, Email: jorshan@yahoo.com, jorshan@nuc.berkeley.edu ABSTRACT: In the IAEA “Milestones in the Development of a National Infrastructure for Nuclear Power”, the importance of nuclear safety, security, and safeguards /nonproliferation (3S) in the peaceful use of nuclear energy was recognized. In 3S, nuclear safety deals with the prevention and mitigation of nuclear accidents and the release of radioactivity; nuclear security deals with the prevention and detection of and response to the theft, sabotage, unauthorized access, illegal transfer, or other malicious acts involving nuclear and radiological materials or their associated facilities; and nuclear safeguards/nonproliferation deals with the prevention of the spread of nuclear weapons, or materials used in fabricating such weapons. In the aftermath of the Fukushima accident in March 2011, issues associated with managing and disposing of used nuclear fuel moved “front-and-center”. The event exposed the safety concern in prolong storage of used fuel in water pool, it also highlighted the intractably technical, institutional, and societal problems in used-fuel management. Used fuel contain the radioactivity which if released, could cause a widespread radiological consequences and environmental contamination. They also contain materials (i.e., unfissioned235U and plutonium) that if separated, are the aspired targets for terrorists, and perhaps even for the host countries producing such materials for use in improvised or stockpiled nuclear devices. Thus, used-fuel management involving advanced reprocessing technologies has all the characteristics of 3S. Advanced reprocessing technology employing pyro-processing recovers from used fuel the transuranic that contains plutonium; minor actinide (i.e., neptunium, americium, curium); and a small percentage of lanthanide for recycling in future metal-fuel fast reactors. The pyro technology is advocated as proliferation resistant because plutonium is not cleanly separated. The advanced aqueous process based on selective adsorption technology aims to separate plutonium and minor actinide cleanly for recycling in existing LWRs and future fast reactors. The aqueous technology is advocated as beneficial to radioactive waste management. The questions of “what is the motivation for used-fuel treatment technologies?” and “what is the role which advanced reprocessing technologies can play in nuclear fuel cycle and radioactive waste management?” would be assessed here, in the context of the nuclear 3S. KEYWORDS: 3S, nuclear safety, security, safeguards, used fuel, advanced reprocessing technologies, pyro-processing, aqueous process based on selective adsorption technology. Viewpoints expressed here are those of the author and not necessarily those of his affiliation. 7
  13. 13. Flexible Fuel Cycle Initiative to Cope with the Uncertainties after Fukushima Daiichi NPP Accident Tetsuo Fukasawa Hitachi-GE Nuclear Energy, Ltd. 3-1-1 Saiwai, Hitachi, Ibaraki, 317-0073 Japan, Tel: +81-294-55-4319, Fax: +81-294-55-9904 E-mail: tetsuo.fukasawa.gx@hitachi.com Fast breeder reactors (FBR) nuclear fuel cycle is needed for long-term nuclear sustainability while preventing global warming and maximum utilizing the limited uranium (U) resources. The “Framework for Nuclear Energy Policy” by the Japanese government on October 2005 stated that commercial FBR deployment will start around 2050 under its suitable conditions by the successive replacement of light water reactors (LWR) to FBR [1]. Even after Fukushima Daiichi Nuclear Power Plant accident which made Japanese tendency slow down the nuclear power generation activities, Japan should have various options for energy resources including nuclear, and also consider the delay of FBR deployment and increase of LWR spent fuel (LWR-SF) storage amounts. As plutonium (Pu) for FBR deployment will be supplied from LWR-SF reprocessing and Japan will not possess surplus Pu, the authors have developed the flexible fuel cycle initiative (FFCI) for the transition from LWR to FBR [2]. This FFCI system is also effective after the Fukushima accident for the reduction of LWRSF and future LWR-to-FBR transition. The outline of FFCI shown in Fig. 1 consists of U removal as LWR-SF reprocessing and Pu+U(+MA) recovery as reprocessing of U removal residue (recycle material, RM) and FBR-SF. The U removal residue has less than 1/10 of the LWR-SF amounts and higher Pu concentration with FP, which enables the compact interim Pu storage with high proliferation resistance and compact Pu+U(+MA) recovery just before FBR use. Removed U is easily re-enriched after purification for LWR reuse. MA would be recovered from stored RM after the development of partitioning and transmutation technology. In this work, the amounts of Pu, reprocessing, LWR-SF were calculated and compared for the FFCI and the ordinary cycle with full LWR/FBR-SF reprocessing, which revealed that the FFCI could supply enough Pu and no excess Pu to FBR in any cases. [1] Atomic Energy Commission of Japan, “Framework for Nuclear Energy Policy”, October 11, 2005. [2] T. Fukasawa, et al., “Flexible LWR-to-FBR Transition Fuel Cycle System”, Proc. GLOBAL 2011, No. 355737, Makuhari, Japan, December 11-16, 2011. LWR Spent fuel Most U removal RM Storage Fresh Pu+U(+MA) fuel recovery FBR Recovered U Fresh fuel U Storage FP(+MA) Spent fuel RM: Recycle Material, most U removal residue which contains Pu+U+MA+FP MA: Minor Actinides, Np+Am+Cm; FP: Fission Products Fig. 1 The outline of Flexible Fuel Cycle Initiative (FFCI) system 8
  14. 14. Advanced Fuel Cycle : Status and Technology Development at KAERI J.H. Leea,*, H.S. Leeb,c,*, J.W. Leec, J.M. Hurc, J.K. Kimc, S.W. Paekc, I.J. Choc, W.I. Koc, I.T. Kimc, G.I. Parkc and H.D. Kimb, c a Department of Nanomaterials Engineering, and bGraduate School of Green Energy Technology, Chungnam National University, 79 Daehak-ro, Yuseong-gu, Daejeon 305-764, Republic of Korea c Nuclear Fuel Cycle Process Development Division, Korea Atomic Energy Research Institute, 1045 Daedukdaero, Yuseong, Daejeon 305-353, Republic of Korea * Corresponding author: jonglee@cnu.ac.kr, hslee5@kaeri.re.kr Pyroprocessing technology has been actively developed at Korea Atomic Energy Research Institute (KAERI) to meet the necessity of addressing spent fuel management issue. This technology has advantages over aqueous process such as less proliferation risk, treatment of spent fuel with relatively high heat and radioactivity, and compact equipments. This presentation describes the pyroprocessing technology development at KAERI from head-end process to waste treatment as well as safeguards R&D. The unit process with various scales has been tested to produce the design data associated with scale-up and selected data will be presented in this presentation. Pyroprocess integrated inactive demonstration facility (PRIDE) was constructed at KAERI and it began test operation in 2012. The purpose of PRIDE is to test the process regarding unit process performance, remote operation of equipments, integration of unit processes, scale-up of process, process monitoring, argon environment system operation, and safeguards-related activities. The test of PRIDE will be promising for further pyroprocessing technology development. Fig. 1. Exterior of PRIDE (left) and Bird’s-eye view of argon cell (right) 9
  15. 15. The Nuclear Education and Training Program at University of California Irvine Mikael Nilsson1*, George Miller2, A.J. Shaka2 1 Department of Chemical Engineering and Materials Science, 2 Department of Chemistry, University of California Irvine, Irvine, CA 92697-2575 * Corresponding author: nilssonm@uci.edu As we project into the future it is clear that the demand for energy, and especially clean energy, will rise. Concerns about rising CO 2 levels in the atmosphere have turned many eyes back again towards nuclear energy. In the last few years the interest in nuclear energy has increased not only in the US but in other parts of the world. In spite of unfortunate incidents, issues with nuclear power plants and their siting appear to be solvable with future generation reactor designs, and better attention to siting requirements. One issue that clearly needs research and development is the handling of nuclear materials both in preparation of new fuels and in handling spent fuels. The result is that the demand for personnel with the right type of training is increasing. Furthermore, recent events that have received much attention in the media surrounding the nuclear power plants in southern California is a clear indication that education, and particularly education of the public, in this region is needed now more than ever. At the University of California Irvine our Nuclear Group has, in the last few years, focused on training and research in the critical associated fields of radiochemistry, nuclear chemical engineering and nuclear materials. A previous radiochemistry program existed [1] and although most of the faculty from that time are gone the infrastructure remains, including a 250kW TRIGA reactor, which serves as the flagship of our program. Our current program includes 6 full-time faculty and staff members, 12-15 graduate students and 8-10 undergraduate students all involved in nuclear science research. The number of students involved has grown from none in 2008 to around 25 graduate and undergraduate students in 2013. The student demographics in our program consist of chemical engineering, materials science engineering, and chemistry majors making the current emphasis of our program on radiochemistry and nuclear chemistry. To strengthen our mission, UCI recently became part of the SUCCESS PIPELINE nuclear science security consortium [2], a group funded by the National Nuclear Security Administration (NNSA) to work on issues broadly related to nuclear security. This consortium has as its primary goal to ensure that there is a nuclear science educated workforce in the US. Collaboration with minority serving institutes is highly encouraged so that individuals from all backgrounds can have an opportunity to be included in the future nuclear science workforce. Within our program there are ample opportunities for collaborations and internships in the areas of nuclear energy (including reactor operations, and instrumentation), nuclear medicine, environmental remediation studies, and nuclear forensics. Please contact the authors with inquires about our program. [1]. V.P. Guinn, G.E. Miller, F.S. Rowland. Radiochemistry teaching and research at UC Irvine, Nucl. Technol., 27, 1, 124, (1975). [2]. http://nssc.berkeley.edu/ (Accessed Oct 14, 2013) 10
  16. 16. Session 2: Basic Chemistry of Actinides and Fission Products 11
  17. 17. Utilization of Technetium and Actinide Compound Synthesis and Coordination Chemistry for the Nuclear Fuel Cycle: Exploring Separations, Fuels, and Waste Forms K.R. Czerwinskia, A. Bhattacharyyaa, J. Droesslera, W. Kerlina, E. Johnstonea, F. Poineaua, P. Wecka, E. Kima, P. Forstera, T. Hartmanna, and A. Sattelbergera,b, a Radiochemistry Program, University of Nevada, Las Vegas, Las Vegas, Nevada, USA b Energy Engineering and Systems Analysis Directorate, Argonne National Laboratory * Corresponding author: czerwin2@unlv.nevada.edu Radiochemistry is a discipline that explores chemical and nuclear properties of elements and their isotopes. Within radiochemistry technetium and the actinides elements are unique in that they lack stable isotopes. These radioelements are germane to nuclear technology and also represent an underexplored section of the periodic table. The actinide elements compose the fuel in reactors and are produced from neutron capture. In the nuclear fuel cycle technetium has a unique role. It is produced at a significant level and is an important fission product for waste consideration. Compared to other elements on the periodic table, technetium and the actinides is less explored, especially in areas of compound synthesis and coordination chemistry. The nuclear fuel cycle offers opportunities to investigate fundamental and applied technetium and actinide chemistry in more detail, with fundamental complexation chemistry providing insight into waste forms, fuels, and separations. Examples are given for technetium and actinide solution and solid phases, with the coordination chemistry explored by spectroscopy and diffraction. An overview on technetium waste forms is provided, highlighting the need for fundamental information on this element to improved synthetic routes and understand resulting behavior. The thermal and hydrothemal based synthesis of technetium compounds is described. Spectroscopic and diffraction results are provided. Trends in the products from computation [1] and experiment are discussed, emphasizing the role of technetium-technetium interaction with oxidation state change. For waste forms, low valent or metallic phase formation demonstrates enhanced inter-technetium interactions which grants the resulting compounds resistance to corrosion or limits solubility. Development of advanced fuels can leverage innovative synthetic techniques that are utilized in the laboratory and non-nuclear industry. In particular methods that use novel reactions with common starting materials can be applied to produce fuels with suitable attributes for advanced fuel cycles. An example is provided based on the formation of uranium mononitride from dinitride starting material [2]. Uranium dinitride is air stable and can be produced from oxide starting material. Uranium dinitride pellets can be formed in air and then sintered under inert atmosphere to produce uranium mononitride. The unique method for the nitride synthesis can be coupled with established sintering techniques to produce fuel. These waste form and fuel illustrations exemplify the utility synthesis reactions can play in the future fuel cycles. A final example is provided on the utility of radioelement synthesis and coordination chemistry in solutions. In one case the use of ionic liquids as a novel media for nuclear separations is presented, emphasizing electrochemistry of the actinides. Understanding the dissolution chemistry and potentials of electrodeposition for actinides and lanthanides in the tri-methyl-n-butyl ammonium n-bis(trifluoromethansulfonylimide) ([Me3NBu][TFSI]) ionic liquid is explored. Studies of the species in the ionic liquid using UV-Visible and X-ray spectroscopy have been performed, along with electrochemistry studies and scanning electron microscopy examination of deposited phases. A method of direct dissolution is currently being investigated and has been successful for a uranium oxide and lanthanide carbonates [ 3,4]. Determining the mechanism of uranium dissolution is the near term 12
  18. 18. goal of this research. Initial data support the conclusion that the dissolved uranium species in the ionic liquid is UO22+ .The equatorial coordinating oxygens could be from the small amount of water present or the sulfonyl on the [TFSI] anion. The cyclic voltammetry of U in [Me3NBu][TFSI] shows that the system can support investigation of 5 V potential windows. The electrochemistry also shows a complex series of peaks for U in [Me3NBu][TFSI]. From the initial results the examined ionic liquid system provides the necessary components to provide separations of actinides and lanthanides from spent nuclear fuel. Solution based separation of trivalent lanthanides from Am and Cm is also provided as an example of the utility of speciation and coordination chemistry in the nuclear fuel cycle. Soft donor ligands such as dithiophosphinic acids and bis-1,2,4-triazinylpyridine/bipyridine (BTP/BTBP) derivatives show significant separation selectivity. Many of these ligands are limited by poor stability, constrained working pH range, solubility in suitable solvents, and competition from counter anions. Various triazinyl and bis-triazinylpridine (H, Methyl, Ethyl, Pyridyl and Phenyl) derivatives have been synthesized and their complexation with Eu3+, Tb3+ and Cm3+ by time resolved laser fluorescence spectroscopy presented. The solvent is found to play a significant role in the complexation behavior and resulting speciation and coordination. In the acetonitrile medium, the complexes contain one ligand molecule per metal ion. Spectroscopic signatures change to ML3 species in methanol medium. For hard acceptors acetonitrile is known to be less solvating as compared to methanol. The Eu3+ ion, being a hard cation, is less solvated by acetonitrile and the nitrate counter anion strongly binds with it and the BTP molecules. When the Eu(III) complex of Py-BTP was prepared in acetonitrile medium, the single crystal XRD result shows that it acts as a tetra-dentate ligand with the stoichiometry Eu(Py-BTP)(NO3)3 resulting in 10 coordinated Eu(III) ion. The overall results show the utility of radioelement speciation, compound synthesis, and coordination chemistry in expanding general chemistry knowledge and the development of applications exploiting radionuclide synthesis, speciation, and coordination chemistry. 1. Weck, P.F., Kim, E., Poineau, F., Rodriguez, E.E., Sattelberger, A.P., Czerwinski, K.R. Inorg. Chem. 48(14), 6555-6558 (2009). 2. Yeamans, C.B., Silva, G.W.C, Cerefice, G.S., Czerwinski, K.R., Hartmann, T., Burrell, A.K., and Sattelberger, A.P. J. Nucl. Mat. 347, 75-78 (2008). 3. Hatchett, D.W., Droessler, J., Kinyanjui, J.M., Martinez, B., Czerwinski, K.R. Electrochim. Acta, 89, 144-151 (2013). 4. Pemberton, W.J., Droessler, J.E., Kinyanjui, J.M., Czerwinski, K.R., Hatchett, D.W. Electrochim Acta., 93, 264-271 (2013). Figure 2. liquid. Figure 1. EXAFS data showing uranyl in the ionic The data show the formation of oxidized uranium from species dissolution. Computation study on Tc halides showing difference with the iodine system. 13
  19. 19. Heptavalent State of Transuranium Elements, Technetium and the Other Elements of the Periodic Table K.E. Germana,*, K. Czerwinskib, M.S. Grigorieva, A.V. Safonov a, F. Poineaub, V.F. Peretrukhina a A.N. Frumkin Institute of Physical Chemistry and Electrochemistry RAS 31, Leninsky prospekt, Moscow, 119071, Russia. * - guerman_k@mail.ru b University of Nevada Las Vegas, LasVegas, USA The discovery of new compounds where transuranic elements are present in heptavalent oxidation state (1967, 1974 [1, 2]) has been the front point for its identification as a more complicated (relative to lanthanides) group in the Periodic table. This observation initiated profound comparison of these compounds to the elements of the 4th – 6th periods. Simulteneously, it formed a critical view at the limitations that were prescribed to the lighter elements in their highest oxidation states. In the transition from one chemical element to the next at the beginning of each period of the Periodic Table the maximum oxidation state of the elements monotonically increases from one to seven, after that only Ru and Os in the 5th and 6th periods continue this pattern, being oxidized up to octavalent state. In all other periods heptavalent elements are followed by elements of lower than +7 maximum valences. The heptavalent state of Np, Pu and Am was unforeseen by the actinide conception. Its discovery led to series of discussions about the similarities and differences between properties of the heptavalent transuranic elements (TRU) and elements of Group VII of the short form of the Periodic Table, indicating the need for further development of the actinide conception [3,4]. Current work continues the discussion with the use of data on the crystal structure of the new compounds of heptavalent elements published in recent years. Halogenide(VII) derivatives and heptavalent d-elements (Mn, Tc, Re) have many similarities in structure and properties. However they have some interesting differences concerning not only the redox properties, which is quite evident and understandable, but also unexpected differences in the composition and properties of their crystalline hydrates [5,6], the structure of the oxides ([7]) and acids such as [TcO 3 (OH)(H 2 O) 2 ] [8-10]. TcO 3 (H 2 O) 2 (OH) Na4 [AnO 4 (OH) 2 ](OH)∙2H 2 O [13] [10] Solid compounds of transuranic elements (VII) are obtained up to date for Np and Pu, both by solid phase reactions, and from aqueous alkaline solutions. Each year, several new compounds of heptavalent TUE are synthesized and their crystal structure is determined. TRU(VII) compounds are varied in composition and can be regarded as containing anions AnO 6 5-, AnO 5 3-, [AnO 4 (OH) 2 ]3-, [An 2 O 8 (OH) 2 ]4- and AnO 4 - [11-17]. For a number of compounds formally containing the first two types of anions the isostructurality to the corresponding ortho- and mesorhenate was established. Unlike them, compounds formally containing anions AnO 4 -, are not analogues of compounds with such a composition, formed by the elements of the seventh group of the Periodic table, and in fact they do not contain single-charged tetraoxide anions. As it was established by one of us earlier, compounds of the type MAnO 4 (·nH 2 O) (M - alkali metal) are analogs of alkaline-earth metal uranate (VI). They contain shortened linear groups AnO 2 3-, combined by bridging O atoms in the anionic layers [13]. Presence of the linear [O = An = O] groups in the crystal structure of Np, Pu, Am compounds again indicates that the "yl" group is a characteristic feature of transuranic compounds in 14
  20. 20. higher oxidation states V, VI, VII and at the same time does not appear in the structure of the compounds of heptavalent halogens and heptavalent Mn, Tc, Re (being present just in several Tc(V)O 2 + complexes). Compounds with anions [AnO 4 (OH) 2 ]3- are synthesized from solutions in the form of monocrystals. Recently, systematic studies on the synthesis and X-ray analysis of Np(VII) and Pu(VII) compounds of such a type have been carried out. Crystal structures of a range of Np(VII) compounds previously defined were specified. About 20 new compounds of An(VII) were synthesized, for the first time including 10 Pu(VII) compounds in the form of single crystals, their crystalline structures were defined. Generally Pu(VII) compounds are isostructural to the corresponding Np(VII) compounds, which confirms the chemical similarity of heptavalent neptunium and plutonium. Among the synthesized and examined compounds there are compounds of two new types: mixed-cationic containing two different alkali metals and Na 4 [AnO 4 (OH) 2 ](OH)·2H 2 O (An = Np, Pu) compounds containing outer OH-groups. [AnO 4 (OH) 2 ]3anions form tetragonal bipyramide in which OH-groups are in apical positions at distances An-O ~ 2.3-2.4 Å, and An= O distance in almost perfectly symmetrical square AnO 4 is ~ 1.9 Å. Distances An = O in AnO 4 groups change slightly from Np(VII) to Pu(VII). At the same time, there is a significant shortening of AnO (OH) bonds. Thus, actinide contraction in the Np(VII) and Pu(VII) compounds is anisotropic. For the first time it was found out that [AnO 4 (OH) 2 ]3- anions can occupy general positions, the orientation of OH-groups differing significantly from centrosymmetric one. Data obtained in recent years on the crystal structure of the new compounds of heptavalent neptunium and plutonium, pertechnetate and perrhenate confirm the earlier prevailing opinion [11] about the absence of a deep similarity in physico-chemical properties between the heptavalent transuranic elements and the elements of Group VII of the short form of the Periodic table and the formal nature of some of the structural similarities among the considered heptavalent compounds. References. 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. Крот Н.Н., Гельман А.Д. Докл. АН СССР, 1967, т.177. № 1. С. 124-126. Крот Н.Н., Шилов В.П., Николаевский В.Б., Пикаев А.К., Гельман А.Д. Докл. АН СССР, 1974, т.217. № 3. С. 589-592. Keller C., Seiffert H. Inorg.Nucl. Chem. Letters, 1969, vjl.5, p.1205-1208. Крот Н.Н., Гельман А.Д., Спицын В.И. ЖНХ, 1969, т. 14, с. 2633-2637. A.Ya. Maruk, M.S. Grigor’ev, K.E. German. // Russian Journal of Coordination Chemistry, 2011, Vol. 37, No. 6, pp. 444–446. Герман К.Э., Крючков С.В., Беляева Л.И. // Известия АН ССР - Сер.хим. 1987, № 10, стр. 2387. Rard, J.A., Rand, M.H., Andregg, G., Etc. Chemical Thermodynamics, Vol. 3. Chemical Thermodynamics of Technetium (M.C.A. Sandino and E. Östhols, eds.), OECD Nuclear Energy Agency, Data Bank, Issy-les-Moulineaux, France 1999, 567 p. F. Poineau, Ph. Weck, K. German, K. Czerwinski etc. // Dalton Trans. (2010) 39 (37), pp. 8616-8619. K. German, A. Maruk, F. Poineau, Ph. Weck, G. Kirakosyan, V. Tarasov, K. Czerwinski. In: 7th International Symposium on Technetium and Rhenium – Science and Utilization – Book of Proceedings - July 4 -8, 2011, Moscow, Russia (Eds.: K.E. German, B.F. Myasoedov, G.E. Kodina, A.Ya.Maruk, I. D. Troshkina). Publishing House GRANITSA, Moscow 2011, p. 99-100. F. Poineau, B. P. Burton-Pye., A. Maruk, K.Czerwinski et al. Inorganica Chimica Acta, 2013, vol. 398, p. 147–150. Krot, N. N., Gel’man, A. D., Mefod’eva, M. P., Shilov, V. P., Peretrukhin, V. F., Spitsyn, V. I.: Semivalentnoe Sostoyanie Neptuniya, Plutoniya, Ameritsiya. Nauka, Moscow (1977) [in Russian]. English translation: The heptavalent state of neptunium, plutonium and americium, UCRL TRANS11798 (VAAP/SA-81/27), LLNL, Livermore (CA 94550) (1981). Grigoriev M. S., Krot N. N. Plutonium Futures “The Science” 2008. Dijon, France, 7-11 July, 2008. Abstracts Booklet. P. 282-283. Grigoriev M. S., Krot N.N. Acta Crystallogr. Sect. С: Crystal Structure Communications. 2009. V. 65, N 12. P. i91-i93. Krot N. N., Charushnikova I. A., Grigoriev M. S. Actinide contraction in compounds of oxygenated actinide ions. XVIII Менделеевский съезд по общей и прикладной химии. Москва, 23-28 сентября 2007 г. Тезисы докладов. Т. 5. С. 299. 15
  21. 21. DFT Study on a Trivalent Uranium Complex Promoted Functionalization of Carbon Dioxide and Carbon Disulfide Dongqi Wang1,*, Zhifang Chai1, Wanjian Ding2, Weihai Fang2 1 CAS Key Laboratory of Nuclear Radiation and Nuclear Energy Techniques, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing, 100049 2 College of Chemistry, Beijing Normal University, Beijing, 100875 dwang@ihep.ac.cn We report a DFT mechanistic study on the functionalization of CO2 and CS2 promoted by a trivalent uranium complex (Tp*)2UCH2Ph. In the calculations, the uranium atom is described by a quasi-relativistic 5f-in-core ECP basis set (LPP) developed for the trivalent uranium cation, which was qualified by the calculations with a quasi-relativistic small core ECP basis set (SPP) for uranium. According to our calculations, the functionalization proceeds in a stepwise manner, and the CO2 or CS2 does not interact with the central uranium atom to form a stable complex prior to the reaction due to the steric hindrance from the bulky ligands but directly cleaves the U−C (benzyl) bond by forming a C−C covalent bond. The released coordination site of uranium is concomitantly occupied by one chalcogen atom of the incoming molecule and gives an intermediate with the uranium atom interacting with the functionalized CO2 or CS2 in an η1 fasion. This step is followed by a reorientation of the (dithio)carboxylate side chain of the newly formed PhCH2CE2−(E = O, S) ligand to give the corresponding product. Energetically, the first step is characterized as the rate-determining step with a barrier of 9.5 (CO2) or 25.0 (CS2) kcal/mol, and during the reaction, the chalcogen atoms are reduced, while the methylene of the benzyl group is oxidized. Comparison of the results from SPP and LPP calculations indicates that our calculations qualify the use of an LPP treatment of the uranium atom toward a reasonable description of the model systems in the present study. Reference: [1] E. M. Matson, W. P. Forrest, P. E. Fanwick, S. C. Bart, J. Am. Chem. Soc. 2011, 133: 4948. [2] W. Ding, W. Fang, Z. Chai, D. Wang, J. Chem. Theory Comput. 2012, 8, 3605-3617. 16
  22. 22. Using Phosphonates to Probe Structural Differences Between the Transuranium Elements and Their Proposed Surrogates Juan Diwua,*, Thomas E. Albrecht-Schmittb a School of Radiation Medicine and Protection (SRMP) and School of Radiological and Interdisciplinary Sciences (RAD-X), Soochow University, Suzhou, Jiangsu 215123, China b Department of Chemistry and Biochemistry, Florida State University, 102 Varsity Way, Tallahassee, Florida 32306-4390, USA * Corresponding author: diwujuan@suda.edu.cn Transuranium elements, especially plutonium, play a special role in advanced technological societies. However, owing to their radioactivity and toxicity, the related research is severely restricted. One of the outcomes of this is the use of less toxic and less or non-radioactive surrogates for transuranium elements. These include early transition metals, especially Zr4+, lanthanides (e.g. Ce4+ and Eu3+), and the early actinides, thorium and uranium. The most central question is: do these surrogates actually mimic the chemistry of transuranics? In this work, we focused on the actinide diphosphonate system, for their importance in nuclear remediation and actinide separation processes, to answer the aforementioned question. Recently, we have crystallized trivalent, tetravalent and hexavalent transuranic diphosphonate compounds as well as their surrogates. In the trivalent series, plutonium and americium compounds were synthesized. In the tetravalent series, Ce4+ and Pu4+ were mainly explored, along with Th4+, U4+ and Np4+. The structural types vary from zero-dimensional clusters, one-demensional chains, to three-dimensional frameworks. PuO22+ phenylenediphosphonate is the only transuranic hexavalent compound that we were able to synthesize. There are a number of uranyl phases that can be compared to. Additionally, in order to study the interaction between different elements, experiments of mixing Np4+ and Pu4+ with both each other and with Ce4+ or UO22+ were conducted, which yielded both ordered and disordered heterobimetallic 4f/5f and 5f/5f phosphonates. In most of the series, significant differences are found between transuranium elements and their surrogates. There are examples where isostructural series exist, but transuranium elements still have their unique properties, which are not mimicked by the surrogates. Reference: J. Diwu and T. E. Albrecht-Schmitt, in Metal Phosphonates, chapter 19, transuranium phosphonates (Eds: Abraham Clearfield, and Konstantinos Demadis), RSC Publishing, London, 2011. 17
  23. 23. From Thorium to Curium: Unprecedented Structures and Properties in Actinide Borates Shuao Wanga,*, Evgeny V. Alekseevb, Thomas E. Albrecht-Schmittc a School of Radiation Medicine and Protection (SRMP) and School of Radiological and Interdisciplinary Sciences (RAD-X), Soochow University, Suzhou, Jiangsu 215123, China b Institute for Energy and Climate Research (IEK-6), Forschungszentrum Jülich GmbH, 52428 Jülich, Germany c Department of Chemistry and Biochemistry, Florida State University, 102 Varsity Way, Tallahassee, Florida 32306-4390, USA * Corresponding author: shuaowang@suda.edu.cn The use of molten boric acid as a reactive flux for synthesizing actinide borates has been developed in the past two years providing access to a remarkable array of exotic materials with both unusual structures and unprecedented properties. [ThB5O6(OH)6][BO(OH)2]·2.5H2O possesses a cationic supertetrahedral structure and displays remarkable anion exchange properties with high selectivity for TcO4−.[1-3] Uranyl borates form noncentrosymmetric structures with extraordinarily rich topological relationships.[4-5] Neptunium borates are often mixed-valent and yield rare examples of compounds with one metal in three different oxidation states (Fig. 1). [6-7] Plutonium borates display new coordination chemistry for trivalent actinides.[8] Finally, americium and curium borates show a dramatic departure from plutonium borates (Fig. 2), and there are scant examples of families of actinides compounds that extend past plutonium to examine the bonding of later actinides.[9-12] There are several grand challenges that this work addresses. The foremost of these challenges is the development of structure-property relationships in transuranium materials. A deep understanding of the materials chemistry of actinides will likely lead to the development of advanced waste forms for radionuclides present in nuclear waste that prevent their transport in the environment. This work may have also uncovered the solubility-limiting phases of actinides in some repositories such as the Waste Isolation Pilot Plant (WIPP), and allows for measurements on the stability of these materials. [1] S. Wang, E. V. Alekseev, J. Diwu, W. Casey, B. Phillips, W. Depmeier, T. E. Albrecht-Schmitt, Angew. Chem. Int. Ed., 2010, 49, 1057-1060 [2] S. Wang, P. Yu, B. A. Purse, M. J. Orta, J. Diwu, W. H. Casey, B. L. Phillips, E. V. Alekseev, W. Depmeier, D. T. Hobbs, T. E. Albrecht-Schmitt, Adv. Funct. Mater., 2012, 22, 2241–2250 [3] P. Yu, S. Wang, E. V. Alekseev, W. Depmeier, T. E. Albrecht-Schmitt, B. Phillips, W. Casey, Angew. Chem. Int. Ed., 2010, 49, 5975-5977 [4] S. Wang, E. V. Alekseev, W. Depmeier, T. E. Albrecht-Schmitt, Chem. Commun., 2011, 47, 10874-10885 [5] S. Wang, E. V. Alekseev, J. Ling, G. Liu, W. Depmeier, T. E. Albrecht-Schmitt, Chem. Mater., 2010, 22, 2155-2163 [6] S. Wang, E. V. Alekseev, J. Ling, S. Skanthakumar, L. Soderholm, W. Depmeier, T. E. Albrecht-Schmitt, Angew. Chem. Int. Ed., 2010, 49, 1263-1266 18
  24. 24. [7] S. Wang, E. V. Alekseev, W. Depmeier, T. E. Albrecht-Schmitt, Chem. Commun., 2010, 46, 3955-3957 [8] S. Wang, E. V. Alekseev, W. Depmeier, T. E. Albrecht-Schmitt, Inorg. Chem., 2011, 50, 2079-2081 [9] M. J. Polinski, D. J. Grant, S. Wang, E. V. Alekseev, J. N. Cross, E. M. Villa, W. Depmeier, L. Gagliardi, T. E. Albrecht-Schmitt, J. Am. Chem. Soc., 2012, 134, 10682-10692 [10] M. J. Polinski, S. Wang, E. V. Alekseev, W. Depmeier, G. Liu, R. G. Haire, T. E. Albrecht-Schmitt, Angew. Chem. Int. Ed., 2012, 51, 1869-1872 [11] M. J. Polinski, S. Wang, E. V. Alekseev, W. Depmeier, T. E. Albrecht-Schmitt, Angew. Chem. Int. Ed., 2011, 50, 8891-8894 Fig. 1. A view of crystal structure of neptunium borates with three oxidation states of neptunium Fig. 2.The synthesis schemes of trivalent actinide borate compounds and the photo showing the product crystals 19
  25. 25. Diamides of Dipicolinic Acid in Complexation and Separation of Selected Metals Alena Paulenovaa*, Joseph Lapkaa, Vasiliy Babainb, Mikhaliy Alyapyshevb, Jack D. Lawc a Oregon State University, Corvallis, OR, USA Khlopin Radium Institute, St Petersburg, Russia c Idaho National Laboratory, Idaho Falls, ID, USA b * Corresponding author: alena.paulenova@oregonstate.edu. Diamides have undergone significant studies as possible ligands for use in the partitioning of trivalent minor actinides and lanthanides.[1-2] Recent research has led to the development of new nitrogen-containing reagents and methods with significant potential for accomplishing separation of trivalent metals from waste process solutions such as substituted malonic acid diamides derivatives (DIAMEX) and tetra-alkyl-diglycolamides (TODGA).[3] Substituted diamides of dipicolinic acid are of interest due to their pyridine nitrogen in proximity to the carbonyl allowing it to possibly participate in coordination. Previously it was reported that among other dipicolinamides, N,N’-N,N’-ditolyldipicolinamide (EtTDPA) shows the best extractability toward americium with a slight extraction preference over europium.[4] It is known that the addition of the bulky hydrophobic anion like chlorinated cobalt dicarbollide (CCD) tend to increase the extraction of metals by neutral ligands. Many ligands were studied as synergistic additives to CCD. For CCD-based systems lanthanides and Am distribution ratios are usually close to each other, but for some poly-nitrogen compounds in the presence of dicarbollide very high separation factors can be achieved.[5-6] In our previous works the extraction ability of diamides of dipicolinic acid (DPA) in the presence of CCD was studied. It was found that DPA-CCD system selectively extract Am over lanthanides from 1-5 M nitric acid with high separation factors of Am from light lanthanides values (La-Gd). The selectivity of extraction tend to decrease with increasing of metal atomic number: DAm/DLa is > 100; while DAm/DEu does not exceed 4.[7] Understanding the underlying thermodynamic parameters of the metal:ligand interaction can lead to better ligand design for separation purposes. Small changes in the structure can affect the ability of a ligand to coordinate with metal ions in solutions. One method of determining homogenous phase binding constants is to measure the changes in absorbance during titration by UV-Vis spectroscopy. The diamides used in this study (EtTDPA) differ in only the position of the methyl group on the exterior aromatic rings yet display different affinities for varying metal oxidation states. These isomers also exhibit varying behavior within a given cation valency as well. The current work attempts to quantify the thermodynamic parameters of complexation of the trivalent lanthanide neodymium with diamides of dipicolinic acid. Figure 1: Structure of EtTDPA isomers 20
  26. 26. Diamides such as EtTDPA are neutral ligand extractants which require a balance of charge to the extracted metal cation. In the case of nitric acid the counter charge is provided by the nitrate ion, giving the mechanism of extraction: M3+ + 3NO3ˉ + nEtTDPA  nEtTDPA.M(NO3)3 where overbars indicate species contained in the organic phase. CCD exists in the organic phase of polar diluents as the acidic HCCD form. The extraction of cations is indirectly provided by CCD, acting as a charge balancer in the organic phase during a liquid-liquid cationic exchange mechanism [7]: M3+ + xHCCD  M(CCD)x(3-x)+ + xH+ The overall sum of these two equations can then be written as: M3+ + (3-x)NO3ˉ + xHCCD + nEtTDPA  nEtTDPA.M(NO3)3-x(CCD)x + xH+ The N,N’-diethyl-N,N’-ditolyl-dipicolinamides (EtTDPA, Fig. 1) were synthesized by the reaction of thionyl chloride with 2,6-pyridinedicarboxylic acid (dipicolinic acid). The acyl chloride was then reactedwith the desired isomer of N-ethyltoluidine to produce the desired EtTDPA molecule.[7] The purities of the synthesized ligands were checked by elemental analysis. The stability constants of the metal-ligand complexes formed between different isomers of N,N’-diethyl-N,N’-ditolyl-dipicolinamide (EtTDPA) and trivalent neodymium in acetonitrile were determined by spectrophotometric and calorimetric methods. Each isomer of EtTDPA was found to be capable of forming three complexes with trivalent neodymium, Nd(EtTDPA), Nd(EtTDPA) 2, and Nd(EtTDPA)3. Values from spectrophotometric and calorimetric titrations were within reasonable agreement with each other. The order of stability constants decrease in the order Et(m)TDPA > Et(p)TDPA > Et(o)TDPA. The obtained values are comparable to other diamidic ligands obtained under similar system conditions and mirror previously obtained solvent extraction data for EtTDPA at low ionic strengths. [1] Serrano-Purroy, D.; Baron, P.; Christiansen, B.; Glatz, J. P.; Madic, C.; Malmbeck, R.; Modolo, G.. Sep. Purif. Technol., 45, (3) 157-162 (2005) [2] Zhu, Z. X.; Sasaki, Y.; Suzuki, H.; Suzuki, S.; KIMURA, T. Anal. Chim. Acta., 527, (2) 163-168 (2004) [3] Modolo, G.; Asp, H.; Schreinemachers, C.; Vijgen, H. Solv. Extr. Ion Exch., 25, (6) 703-721 (2007) [4] BABAIN, V.A.; ALYAPYSHEV, M.YU.; SMIRNOV, I.V.; SHADRIN, A.YU.. Radiochemistry, 48, (4) 369-373 (2006) [5] Paulenova, A.; Alyapyshev, M.Yu.; Babain, V.A.; Herbst, R.S.; Law, J.D. Sep. Sci. Technol., 43, (9) 2606-2618 (2008) [6] J. Rais, B. Grü Ion Exchange and Solvent Extraction, A Series of Advances, 17, 243-334, by Y. Marcus, A. ner, K. SenGupta, CRC Press, (2004). [7] Paulenova A., Alyapyshev, M. Yu, Babain, V. A. ·Herbst, R. S. ·Law, J. D. Solvent Extraction and Ion Exchange, Solvent Extraction and Ion Exchange, Volume 31, Issue 2, 184-197, 2013 21
  27. 27. Recovery of Uranium by Adsorbents with Amidoxime and Carboxyl Groups: A Density Functional Study Wei-Qun Shi*, Cong-Zhi Wang, Jian-Hui Lan, Zhi-Fang Chai Nuclear Energy Nano-Chemistry Group,CAS Key Laboratory of Nuclear Radiation and Nuclear Energy Technology, Institute of High Energy Physics, Beijing 100049, China * Corresponding author: shiwq@ihep.ac.cn In seawater, uranium is present mainly in the form of UO 2 (CO 3 ) 3 4- with a concentration of about 3-3.3 mg/L. Recovery of uranium from seawater has been studied over several decades [1, 2]. It has been found that adsorbents with amidoxime (HAO) groups show high tendency towards uranium, and the introduction of carboxyl (HAA) groups can increase the adsorption capacity of uranium. In this work, the adsorbent behavior of UO 2 2+ by adsorbents containing amidoxime and carboxyl groups have been studied by density functional theory (DFT) in conjunction with relativistic small-core pseudopotentials. Our results reveal that there are three binding modes for the amidoxime group, i.e. the monodentate coordination with the oxime oxygen atom, the bidentate coordination through the oxime oxygen and the amine nitrogen atoms, and th e η2 coordination via the N-O bond. As for the carboxyl group, it acts as monodentate and bidentate ligand to UO 2 2+. Additionally, amidoximes can form cyclic imide dioximes, which coordinate to UO 2 2+ as tridentate ligands. Natural bond orbital analysis and electron localization function analyses indicate that in these complexes there exist strong U-O and U-N bonding and the species with η2 coordination mode exhibit higher covalent character. As reported in the literature, the co-existence of amidoxime and carboxyl groups can enhance the adsorbability of uranium. The 1:4 (metal:ligand) type complexes are found to be the most stable species with the 1:1 stoichiometry of amidoxime and carboxyl. In these complexes, the amidoxime ligands prefer to coordinate in η2 binding mode to UO 2 2+. Moreover, our calculations also show that these adsorbents have higher adsorbability for vanadium than uranium, which is in accordance with the experimental results. [1] R. Sellin and S. D. Alexandratos, Ind. Eng. Chem. Res. 52, 11792 (2013). [2] H. Egawa, N. Kabay, T. Shuto and A. Jyo, Ind. Eng. Chem. Res. 32, 709 (1993). Fig. 1. Optimized structures of the uranyl complexes with adsorbents containing amidoxime (HAO) and carboxyl (HAA). This work was supported by the National Natural Science Foundation of China (Grant Nos. 21101157, 21201166, 11105162, 21261140335) and the “Strategic Priority Research program” of the Chinese Academy of Sciences (Grant Nos. XDA030104). 22
  28. 28. Theoretical Studies on the Electronic Structure and Chemical Bonding of UX 5– (X = F, Cl) Complexes Jing Sua,b*, Phuong Diem Dauc, Xiao-Gen Xionga,b, Lai-Sheng Wangc, Jun Lib* a Division of Nuclear Materials Science and Engineering, Shanghai Institute of Applied Physics,Chinese Academy of Sciences, Shanghai 201800, China b Department of Chemistry, Tsinghua University, Beijing 100084, China c Department of Chemistry, Brown University, Providence RI 02912, USA * Corresponding author: sujing@sinap.ac.cn (J.S.); junli@mail.tsinghua.edu.cn (J.L.). Molten salts are important in the nuclear energy industry both as coolants and in hydrometallurgical liquid-liquid extraction for reprocessing of spent fuels.[1]Fluoride- and chloride-based salts, such as LiF-BeF 2 andLiCl-KCl melts, are used in pyrochemical nuclear applications due to their radiolytic stability.[2,3] Knowledges of the electronic structures, and chemical and thermodynamic properties of uranium halides, especially fluorides and chlorides, are important to understanding the actinide chemical speciation and redox processes in molten salts. Here we report the gas-phase investigation of the electronic structures of UX 5 –(X = F, Cl) using photoelectron spectroscopy (PES) and relativistic quantum chemistry. [4,5]Theoretical investigations reveal that the ground states of UX 5 –(X = F, Cl) have an open shell with two unpaired electrons occupying two primarily 5f xyz andU 5f z 3based molecular orbitals (8a 1 and 2b 2 respectively, see Fig. 1). The structures of UX 5 – and UX 5 (X = F, Cl)are theoretically optimized and confirmed to have C 4v symmetry.The UX 5 – anionsare highly electronically stable with adiabatic electron binding energies of 3.82±0.05 eV and4.76±0.03eVfor X= F and Cl, respectively. An extensive vibrational progression from U-F symmetrical stretching mode isobserved in the spectra of UF 5 –, which is well reproduced by Franck-Condon simulation.Systematic chemical bonding analysesare performed on all the uranium pentahalide complexes UX 5 – (X= F, Cl, Br, I).The results indicate that the U-X interactions in UX 5 – are dominated by ionic bonding, with increasing covalent contributions for the heavier halogen complexes. Fig. 1.The two singly occupied molecular orbitals in UX 5 –(X = F, Cl) References [1] C. Le Brun, J. Nucl. Mater. 360, 1 (2007). [2] Y.H. Cho, T.J. Kim, S.E. Bae, Y.J. Park, H.J. Ahn and K. Song, Microchem. J. 96, 344 (2010). [3] M. Salanne, C. Simon, P. Turq, R.J. Heaton, P.A. Madden, J. Phys. Chem. B 110, 11461 (2006) [4] P.D. Dau, J. Su, H.T. Liu, D. L. Huang, F. Wei, J. Li and L.S. Wang, J. Chem. Phys. 136, 194304 (2012) [5]J. Su, P.D. Dau, C.F. Xu, D.L. Huang, H.T. Liu, F. Wei, L.S. Wang and J. Li. Chem. Asian J. 8, 2489 (2013). 23
  29. 29. First-principles calculation of intrinsic and defective properties of UO2 and ThO2 Han Hana, Cheng Chenga and Ping Huaia* a Key Laboratory of Nuclear Radiation and Nuclear Energy Technology, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai, China 201800 *Corresponding author: huaiping@sinap.ac.cn The coated particle fuel is originally designed for the high temperature gas-cooled reactor. Recently, several new high temperature reactor concepts have been developed. For instance, small modular Advanced High Temperature Reactor is a new small modular fluoride salt cooled reactor concept developed at Oak Ridge National Laboratory. The Thorium Molten Salt Reactor (TMSR) in China has also proposed a concept design based on pebblebed fluoride salt cooled reactor with thorium-uranium alternate once-through fuel cycle. In the history of coated-particle fuel, the Tristructural Isotropic (TRISO) fuel is one of the most reliable candidates, which has a uranium oxycarbide kernel coated with a series of layers that act as the cladding. The inner pyro-carbon layer is designed to accept gaseous fission products and attenuate fission product recoils. The SiC layer’s function is to contain metallic fission products and provide structural support for the fuel particle. The outer pyro-carbon layer serves as a structural component and protects the SiC layer during compacting. These coated particle fuels have highly robust safety characteristics, with the ability to retain fission products up to temperatures of 1600°C or more. Uranium, thorium and plutonium fuels have been experimentally used in form of oxides, carbides and nitrides in TRISO particles. The behaviour of nuclear fuel in reactor is very complicated due to their neutronics properties as well as thermo mechanical strength, chemical stability, microstructure, and defects. It is very important to understand these material properties from microscopic picture. The complicated bonding nature of 5f-orbital leads to unique electronic structure of actinide compounds [1-2]. In this paper, the properties of intrinsic/defective uranium and thorium dioxide are studied by using the density functional theory in the generalized gradient approximation. A small lattice distortion is found due to the magnetic ordering of ground state of UO2 (as illustrated in Figure 1(a). The lattice constant c0 (parallel to the spin) is different from the other two constants a0 and b0. Strong correlation also plays an important role in UO2. The Hubbard U correction method has been introduced to describe the correlation. By taking into account the Hubbard U correction, the lattice constants are increased to a0=5.57 Å, and c0=5.50 Å. We have also checked the total phonon density of states in case of the small lattice distortion, which was obtained by minimizing the total energy of the electronic structure calculations. The dispersion curves of the distorted UO2 crystal has been shown in Fig. 1(b) with the LO-TO splitting. The U-dependence of the phonon density of states is found to be very weak, which is consistent with the theoretical assumption that excited-state properties of the electronic states should not affect ground-state materials properties very much. Figure 1 (a) The structure and magnetic ordering of ground state of UO2. (b) The phonon dispersion curves of antimagnetic UO2. The LO-TO splitting effect and Hubbard U correction are all concerned. References: [1] G. Schreckenbach, G. Shamov, Acc. Chem. Res. 43, 19 (2010). [2] Kevin T. Moore, Rev. Mol. Phys. 81, 235-298 (2009). 24
  30. 30. Modeling the autocatalytic reaction between TcO 4 - and MMH in HNO 3 solution Fang LIU, Hui WANG, Yan WEI, Yong-fen JIA (China Institute of Atomic Energy, Beijing, 102413) liuxinyu741@sohu.com Abstract An advanced PUREX process was innovated by China Institute of Atomic Energy, which adopts N, N-dimethylhyldroxylamine (DMHAN) as reducing agent and methyl-hydrazine (MMH) as stabilizer in U/Pu splitting stage. MMH is a moderate reductant, it may impact technetium valence so as to decide the technetium distribution in the process. This paper aimed at (i) investigating the reaction between TcO 4 - and MMH in HNO 3 solution with an autocatalytic reaction model. Two equations widely used for modeling autocatalytic reaction are adopted to simulate the reaction, and (ii) studying the concentration effects on kinetic parameters such as maximum reaction rate, lag time. Isothermal experiments were conducted at temperatures ranging from 25°C to 55°C using reactant solutions range wider than the real technology. This concentration effect was included in the proposed kinetic models, which were able to successfully describe experimental data, and further more may be able to predict technetium behaviour in U/Pu splitting stage. The advanced salt-free PUREX process adopts MMH as stabilizer, one of the reason is to avoid producing hydragoic acid which is a product of Hydrazine oxidation. Prior works proved that DMHAN can not reduce Tc(VII) in HNO 3 solution [1], and in the U/Pu splitting stage of advanced salt-free PUREX technetium goes into aqueous solution mainly in Tc(IV) form. The reaction between technetium and hydrazine has been studied by many investigators [2, 3], so we presume that Tc(VII) was mainly reduced by MMH in this system. In this paper the reaction between technetium and MMH was studied detailed in the aspect of Tc(VII) concentration. A typical c-t curve of TcO 4 - reduced by MMH in HNO 3 solution is presented in figure 1. The X axes stands for the growth of low valence Tc. 25000 20000 count(cpm) 15000 10000 experiment dates logic fit gompertz fit 5000 0 2 0 2 4 6 8 10 12 14 time (hour) Fig 1. Growth of low valence technetium depend on time 40°C, c 0 (Tc(VII))=7.4×10-4mol/L, c 0 (HNO 3 )=1.5mol/L, c 0 (MMH)=0.15mol/L This is a typical S mode curve in the reaction of MMH deoxidize Tc(VII). There is a leg phase in the initial moment, then the Tc(VII) concentration declined sharply, in the end of the reaction Tc(VII) concentration decreases slowly again. The logic equation and Gompertz function 25
  31. 31. are widely used for simulating a sigmoid curve. In figure 1 both the two equations can simulate the experiment dates very well. The R-Square is 0.9972 for logic simulation and 0.9951 for Gompertz simulation. The logic equation, Y=a/(1+exp(k*(x-x 0 ))), is one solution of equation dy/dx = k*y*(c 0 -y). And P. D. Willson used equation dTc(VII)/dt = k*Tc(VII)*Tc(IV) to simulate the reaction between TcO 4 - and MMH in HNO 3 solution. The experiment dates can be simulated by the logic equation, it indicates that the reaction of MMH reducing TcO 4 - may be a autocatalytic mode. The low valence Tc, mainly Tc(IV) act a important role in this reaction. The influence of initial Tc concentration, MMH concentration and acidity on the reaction is studied in this paper. The initial Tc concentration has a distinct effect on parameter k of both equations, and has slight effect on x 0 . MMH concentration and acidity effect the x 0 remarkable than k. A higher MMH concentration will get a little x 0 value. There is a proper acidity in this reaction, in this acidity there is a smallest x 0 value. For the mathematics aspect, the parameter k mainly charges the maximum of reaction velocity. The parameter x 0 mainly charges the log period time. That is to say, the initial Tc concentration mainly affects the maximum of reaction velocity, and the MMH concentration and acidity decide when the fastest reaction happens. The influence of MMH concentration is showed in figure 2 and table 1. 50000 40000 count (cpm) 30000 1 2 3 4 5 20000 10000 0 0 2 4 6 8 10 time (hour) Fig.2 The influence of MMH concentration on reaction 40°C, c 0 (Tc(VII))=7.4×10-4mol/L, c 0 (HNO 3 )=1.5mol/L, c 0 (MMH): 1--0.068M, 2--0.15M,3--0.225M, 4--0.34M, 5--0.51M Table 1. The influence of MMH concentration on the parameter of simulation logic simulation Function: y=a/(1+exp(k*(x-x 0 ))) C MMH a k R2 x0 43297 43831 0.225M 46478 0.51M 45318 0.068M 0.15M 0.90 0.84 0.85 0.97 Gompertz simulation Function: y=a*exp(-exp(-k*(x-x 0 ))) a k R2 x0 5.26 0.9974 4.36 0.9975 3.77 0.9978 3.01 0.9930 47290 0.51 4.69 0.9927 50036 0.45 3.87 0.9951 51627 0.48 3.22 0.9964 49068 0.58 2.49 0.9977 References [1] Fang LIU, Master's Thesis of CIAE, 2009 [2] P. D. Wilson, J. Garraway, in Proc. Int. Meet. On Fuel Reprocessing and Waste Management, La Grange Park, (the United States), 1984, vol. 1, p. 467. [3] J. Garraway, Journal of the Less Common Metals, Volume 97, February 1984, pp. 191–203. 26
  32. 32. Fluorescent BINOL-Based Sensor for Thorium Recognition and a Density Functional Theory Investigation Jun Wen, Liang Dong, Sheng Hu, Tong-Zai Yang , Xiao-Lin Wang * Institute of Nuclear Physics and Chemistry, China Academy of Engineering Physics, Mianyang, 621900, Sichuan Province, China * Corresponding author: xlwang@caep.ac.cn. Because of the widespread use of thorium and its toxic properties, the development and improvement in analysis methods for the determination of thorium would be useful [1-3]. We developed a novel 1,1′-bi-2-naphthol (BINOL) derivative fluorescence sensor L-1 for the recognition of thorium ion with a fluorescence quench response. This ligand showed high selectivity and sensitivity for thorium ion recognition (Figure 1). When an equivalent of Th4+ was added to the solution of L-1, dramatic fluorescence quenching ( quenching efficiency: 64%) was observed, suggesting that compound L-1 showed a specific response with Th4+ ions due to the chelation-enhanced fluorescence quenching (CHEQ) effect. This is the first one-to-one stoichiometric responding chemical sensor for thorium, and indicated a 1:1 bonding mode between L-1 and Th4+ ions (Figure 2). The detection limit [4] of L-1 for the determination of Th4+ was estimated to be 6 × 10−7 M in 1:1 MeOH:H2O (v/v). Moreover, the binding constant (K) derived from the fluorescence titration data was found to be 3.4 × 103 using a Benesi–Hildebrand plot [5]. According to previous reports [2], many thorium sensors have encountered interference by uranyl ions. Nevertheless, L-1 displayed good selectivity for thorium. To further understand the nature of the binding interactions of Th4+ and UO 2 2+ with the ligand, coordination effects were investigated by DFT calculations. According to these analyses of structures, electronic properties, and energetics, we can conclude that the binding interaction between L-1 with Th4+ is stronger than that with UO 2 2+, and that the L-1 ligand forms a stable complex with Th4+. [1] Handbook of Hazardous Materials (Ed: M. D. Corn), Academic Press, San Diego 1993. [2] A. Safavi, M. Sadeghi, Anal. Chim. Acta, 567, 184-188, (2006). [3] F. S. Rojas, C. B. Ojeda, Anal. Chim. Acta, 635, 22-44, (2009). [4] V. Thomsen, D. Schatzlein, D. Mercuro, 18, 112-114, (2003). [5] H. A. Benesi,; J. H. Hildebrand, J. Am. Chem. Soc. 71, 2703-2707, (1949). 27
  33. 33. Exceptional Selectivity for Actinides by N,N’-Diethyl-N,N’-Ditolyl-2,9-Diamide-1,10Phenanthroline Ligand: A Combined Hard-Soft Atoms Principle# Cheng-Liang Xiao, Li-Yong Yuan, Yu-Liang Zhao, Zhi-Fang Chai, Wei-Qun Shi* Key Laboratory of Nuclear Radiation and Nuclear Energy Technology and Key Laboratory For Biomedical Effects of Nanomaterials and Nanosafety, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, China * Corresponding author: shiwq@ihep.ac.cn MA(III) and Ln(III) have similar physicochemical properties, such as oxidation state, ionic radii, hydration, and complexation mode. Extractants containing soft sulfur or nitrogen atoms are preferred to recognize MA(III) over Ln(III). R-BTP, R-BTBP, and R-BTPhen ligands are the successful representatives for Ln(III)/MA(III) in the last 20 years [1-2]. However, light actinides (U, Np, Pu) normally favor ligands (alkylamide or alkylphosphate) containing hard oxygen atoms [3]. If we make sure the selectivity for light actinides using hard-atoms ligands, the separation of MA(III) from Ln(III) is difficult to achieve. To separate all the actinides from lanthanides, the synthesis, solvent extraction, and complexation behaviors of actinides and lanthanides by a novel phenanthroline-based tetradentate ligand with combined hard-soft atoms, N,N’-diethyl-N,N’-ditolyl-2,9-diamide-1,10-phenanthroline (Et-Tol-DAPhen, 1), are described in this work. The ligand exhibits excellent extraction ability and high selectivity of actinides over lanthanides from highly acidic solution. X-ray crystallographic structures of Et-Tol-DAPhen with thorium and uranyl ions are showed to be 1:1 complexation. The stability constants for some actinides and lanthanides complexes with Et-Tol-DAPhen are also determined in methanol by UV-Vis spectrometry. The results of density functional theory (DFT) calculation (Fig. 1) reveal that the An-N bonds have more covalent characters than that of Eu-N, which may dominate the selectivity of Et-Tol-DAPhen towards actinides. This work can shed light on the design of new ligands with combined soft-hard atoms for group separation of actinides from highly acidic nuclear waste. [1] J. H. Lan, W. Q. Shi, Z. F. Chai , et al., Coord. Chem. Rev., 256, 1406 (2012). [2] M. J. Hudson, L. M. Harwood, D. M. Laventine, et al., Inorg. Chem., 52, 3414 (2013). [3] C. Z. Wang, J. H. Lan, W. Q. Shi, et al., Inorg. Chem., 52, 196 (2013). (a) (b) (c) (d) Fig. 1. Optimized structures of (a) Am(1)(NO 3 ) 3 , (b) Eu(1)(NO 3 ) 3 , (c) [UO 2 (1)(NO 3 )]+, (d) Th(1) -(NO 3 ) 4 by B3LYP/6-311G(d,p)/RECP method in gas phase. # This work was supported by NSFC (Grants 91026007, 21201166, and 21101157) and the "Strategic Priority Research Program" of the Chinese Academy of Sciences (Grant XDA030104). 28
  34. 34. The studies on optimization of the separation method of Am and Cm Zhuoxin Yin, Ping Li, Wangsuo Wu* Radiochemistry Laboratory, Lanzhou University, Lanzhou 730000, Gansu, China *Corresponding author: wuws@lzu.edu.cn With the development of the nuclear industries, the amount of the spent nuclear fuel continued to grow. According to the concept of advanced nuclear fuel cycle, every element of the HLLW should be separated independently. The method of the element separation depended upon the chemical species of the element and the composition of the samples. Americium and curium are two kinds of highly radioactive and long half-life elements in the HLLW. Because of the similar chemical properties of americium and curium, they are hardly to be segregated. Many techniques had been taken to solve the problem of the separation of Am and Cm, each of them had its advantages and disadvantages. The Solvent Extraction[1] was the most common way for separating Am and Cm, sometimes it used batch and column methods, the lately investigation aimed to synthesize the new ligands and find new complex structures in order to get better spatial results than before. The ionic liquids[2], electrodeposition[3] or adsorption were also taken part in laboratory experiments, in order to find new ways to separate Americium and Curium. Generally, the existences of most transuranium elements in the HLLW were trivalent ions. The Valence Control[4] in some situation might be result in good separated effect. For the sake of the optimization of the separation method of Am and Cm, further research should be made and more experimental data should be obtained. 4.50x10-6 4.50x10-6 4.00x10-6 4.00x10-6 3.50x10-6 3.50x10-6 3.00x10-6 3+ Am Am(OH)+ 2 Am(OH)3 2.50x10-6 2.00x10-6 Species(mol/L) Species(mol/L) 3.00x10-6 Am(OH)2+ 1.50x10-6 1.00x10-6 Cm3+ Cm(OH)+ 2 2.50x10-6 Cm(OH)2+ 2.00x10-6 1.50x10-6 1.00x10-6 5.00x10-7 5.00x10-7 0.00 0.00 -5.00x10-7 0 1 2 3 4 5 6 7 8 9 10 11 12 13 0 14 1 2 3 4 5 6 7 8 9 10 11 12 13 pH pH (a) Species of Am(III) (b) Species of Cm(III) Fig.1. Speciation distribution of Am(III) as function of pH in aqueous solution References: [1] Y. Sasaki, Y, Kitatsuji, Y. Tsubata, Y. Sugo, Y. Morita, Solvent. Extr. Res. Dsv. 18, 93(2011). [2] K. Binnemans, Chem. Rev, 107, 2592(2007). [3] S. Liu, Atomic. Ene. Sci. Technol. 22, 238(1988) [4] K. Marmoru, F. Tetso, K. Fumio, J. Nucl. Sci. Technol. 35, 185(1998). 29 14
  35. 35. Burn-up calculation of plutonium in fusion-fission hybrid reactor Kento Fukanoa*, Shunji Tsuji-Iioa, Hiroaki Tsutsuia, Yoji Someyab a Tokyo Institute of Technology b Japan Atomic Energy Agency *fukano.k.aa@m.titech.ac.jp Introduction Nuclear power plants (NPPs) are important as base load power source in the world even after Fukushima Daiichi nuclear disaster. But NPPs have a problem in terms of nuclear proliferation because plutonium (Pu) is produced when NPP generates electric power. Therefore, Pu should be burned up by some method. On the other hand, ITER which is the international fusion experimental reactor uses 10 kg of tritium (T) as fuel in the start-up phase, and it will exhaust 21 kg of T existing in the world. The world is deficient in T. Therefore T should be produced by some method. A solution to solve these two problems is fusion-fission hybrid reactor. Hybrid reactor can burn up Pu and breed T effectively. The objective of this study is to put forward scenarios for Pu burn-up in terms of nuclear non-proliferation and fusion reactor introduction from the aspect of tritium supply in the world. As preparatory, this study designs hybrid reactors for Pu burn-up and T production with simulation codes. Assumed type of fusion reactor is tokamak by magnetic confinement. The blanket in fusion reactor in this study is comprised of MOX fuel, Li2TiO3, water, F82H, and SUS316LN. Design requirements There are four requirements to design feasible hybrid reactors for Pu burn-up and T breeding, the life time of magnetic field coil is over 40 years, tritium breeding ratio (TBR) is over unity, and the amount of burn-up plutonium per year is over 7 t, the temperature of each composition material is below its upper temperature limit. The first target of this study is to find out hybrid reactor parameters to meet the above requirements with simulation codes. Result and consideration According to simulation results, the life time of magnetic field coil is 50 years, TBR is 4.08. Figure 1 shows a reduction in the total amount of plutonium. The initial loading plutonium is 22 t. After 1 year, it is reduced to 13 t , so that the amount of burn-up plutonium per year is 9 t. Figure 2 indicates the temperature distribution of MOX fuel layers in blanket. The layers include MOX fuel and water in alternate. The upper temperature limit of MOX fuel is 2500℃. Therefore this blanket is feasible thermally as well as other layers. This designed hybrid reactor fulfills the four requirements. The next step is to make up operation scenarios of this hybrid reactor. Fig. 1. Time evolution of total Pu amount Fig. 2. Temperature distribution in blanket 30
  36. 36. [UO2(NO3)4]2- Complex in Ionic Liquids Investigated by Optical Spectroscopic and Electrochemical Studies Yupeng Liu, Taiwei Chu* Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China. * Corresponding author: twchu@pku.edu.cn. The tetranitratouranium(VI) complex, [UO2(NO3)4]2-, is thought to be unstable in common molecular solvents. Recently, C. Gaillard et al. [1] has proven the formation of [UO2(NO3)4]2- in the ionic liquid [BMI][NO3] by EXAFS study. However, the character of this complex in ILs is still unknown. In this report, we studied the optical spectra of [UO2(NO3)4]2-, calculated the formation constants in various ILs, and investigated its electrochemical behaviors. The UV-vis spectrum of [UO2(NO3)4]2- (Fig.1) shows a strong ‘continuous’ broad band in the 380~480 nm region, far from the remarkable sharp vibronic bands of [UO2(NO3)3]- [2]. It can also formed in hydrophobic ILs ([NTf2]-- and [PF6]--based) with excess of [NO3]-. The luminescence of [UO2(NO3)4]2- in non-imidazolium ILs is much stronger than that of [UO2(NO3)3]-, and without vibronic fine structures. By quantitative analysis of UV-vis spectra of serial samples with various nitrate concentrations, the equilibrium constant (K4) of [UO2(NO3)3]- + [NO3]- = [UO2(NO3)4]2- can be gotten. The constants in several hydrophobic ILs are ranging from 10 to 30 (Table.1), much higher than in molecular solvents. ILs with aromatic cations show lower K4 values, because these cations have stronger interactions with the planar [NO3]- anion. Table 1. Formation constant values of [UO2(NO3)4]2- in several [NTf2]—based ILs. Cations Aromatic K4 BMI Y 10.34 BDMI Y 12.08 BPy Y 12.79 N4111 N 15.35 N4221 N 20.04 Pyr14 N 26.48 PP14 N 30.12 CH3NO2 * 4.74 * Nitromethane as solvent, from Ref.[3]. Fig.1. UV-vis spectra of [UO2(NO3)4]2- in [BMI][NO3] and [UO2(NO3)3]- in [BMI][NTf2]. Vibrational spectra show more detailed information on the interactions between [NO3]- and uranyl. The notable redshift (8~10 cm-1 vs. [UO2(NO3)3]-) of uranyl stretching frequencies in both symmetry (Raman) and asymmetry (infrared) modes (Fig.2) indicates the stronger interaction from equatorial ligands. Moreover, the ATR-FTIR spectrum in [NO3]- stretching region shows the presence of two kinds of coordinated [NO3]- in [UO2(NO3)4]2-. In either [BMI][NO3] or [Pyr14][NO3]/[NTf2] (1.2M [NO3]-), [UO2(NO3)4]2- shows a quasi-reversible U(VI)/U(V) electrochemical redox process. In [Pyr14][NO3]/[NTf2], the half-wave potential of U(VI)/U(V) is -1.10 V (vs. Ag+/Ag, 308K), the Ipc/Ipa ratio is ~0.7 while scan rate varies from 0.01 to 0.10 V/s (Fig.3 and Table 2), and the diffusion coefficient D is (2.10±0.06)×10-8 cm2/s. 31
  37. 37. The notable stability of [UO2(NO3)4]2- in ionic liquids suggests that this complex may play an important role in the NFC processes involving ILs containing nitrate anion, and this complex may have potential in the development of IL-based electrochemical separation and purification processes. Fig.2. ATR-FTIR (left) and Raman (right) spectra of [UO2(NO3)4]2- (black) and [UO2(NO3)3](grey) in the O=U=O stretching region. Table 2. Reversibility of U(VI)/U(V) redox of [UO2(NO3)4]2- in[Pyr14][NO3]/[NTf2]. Scan rate Ε1/2 ∆Ep Ipa/Ipc V/s V* mV 0.01 -1.105 154 0.65 0.02 -1.100 146 0.68 0.03 -1.098 143 0.70 0.05 -1.096 137 0.70 0.07 -1.095 132 0.69 0.10 -1.095 135 0.67 + * Potential against Ag /Ag. Fig.3. Cyclic voltammograms of [UO2(NO3)4]2at various scan rates in [Pyr14][NO3]/[NTf2]. Insert: the linear relationship of Ipc against square root of scan rate. T = 308K. [1] C. Gaillard, O. Klimchuk, A. Quadi, I. Billard and C. Hennig. Dalton Trans., 41, 5476 (2012) [2] K. Servaes, C. Hennig, I. Billard, C. Gaillard, K. Binnemans, C. Gorller-Walrand, and R. Van Deun. Eur. J. Inorg. Chem., 2007, 5120 (2007) [3] J. L. Ryan. J. Phys. Chem., 65, 1099 (1961) 32
  38. 38. Complexation of Uranyl by Neutral Bidentate Phosphonate Ligands in Ionic Liquids Yupeng Liu, Taiwei Chu* Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China. * Corresponding author: twchu@pku.edu.cn. The potentiality of ionic liquids (ILs) in the nuclear industry has been explored in recent years, especially for the extraction of uranium from aqueous medium using ILs [1]. Knowledge on the interactions between uranyl and the extracting agents (ligands) in ILs is important to understand the extraction progress. Recently, we have reported a unique 2:1 dicationic complex, [UO 2 (TEMBP) 2 ]2+, formed by a bidentate ligand tetraethyl methylenebisphosphonate (TEMBP) and uranyl in ILs [2].The optical spectra and electrochemistry of uranyl complexes of some monodentate organophosphorus ligands have also been studied by our group [3]. In this report, we studied the uranyl complexes formed in [BMI][NTf 2 ] with bidentate ligands related to TEMBP, the compete complexation between chelate ligands and NO 3 , and the spectra of uranyl complexes extracted from nitrate solutions. Fig.1 shows the UV-vis spectra of uranyl complexes formed from UO 2 (ClO 4 ) 2 . Complexes similar with [UO 2 (TEMBP) 2 ]2+ are formed by bidentate liands such as tetrabutyl methylenebisphosphonate (TBMBP) and tetrabutyl ethylenebisphosphonate (TBEBP). Since these complexes have similar structure, their spectra (b, c, d) resemble each other. Their spectra also have some similarity with those of [UO 2 (TBP) 4 ]2+ and [UO 2 (DBBP) 4 ]2+ (a, b), because they all have tetragonal coordination to the uranyl by P=O groups [2,3]. Fig. 1. UV-vis spectra of uranyl complexes in [BMI][NTf 2 ]. (a), [UO 2 (TBP) 4 ]2+; (b), [UO 2 (DBBP) 4 ]2+; (c), [UO 2 (TEMBP) 2 ]2+; (d), [UO 2 (TBMBP) 2 ]2+; (e), [UO 2 (TBEBP) 2 ]2+. Fig. 2. UV-vis spectra of samples in [BMI] -[NTf 2 ]. (a) ~ (e), uranyl nitrate with 1 to 10 eq. of TEMBP; (f), [UO 2 (TEMBP) 2 ]2+; (g), [UO 2 (TBP) 4 ]2+; (h), uranyl nitrate with 1M TBP; (i), [UO 2 (NO 3 ) 2 (TBP) 2 ] in pure TBP. Results of compete complexation between ligands and NO 3 - are showing in Fig.2. With 1 equivalent molar of TEMBP added, [UO 2 (NO 3 ) 2 (TEMBP)] complex is formed in [BMI][NTf 2 ] (a). The spectra then change gradually with increasing TEMBP concentrations, as evidenced by the shrink of characteristic bands of [UO 2 (NO 3 ) 2 (TEMBP)] (b ~ e) and emerging of new bands those belonging to [UO 2(TEMBP) 2 ]2+ (f). The changes in spectra indicate that excess of TEMBP can replace the coordinated NO 3 - in [UO 2 (NO 3 ) 2 (TEMBP)] to form [UO 2 (TEMBP) 2 ]2+ in the IL. In contrast, [UO 2 (NO 3 ) 2 (TBP) 2 ] is the complex formed by uranyl nitrate with even large excess of TBP (h), with its spectrum similar with that of [UO 2 (NO 3 ) 2 (TBP) 2 ] in pure TBP (i) and much different from [UO 2 (TBP) 4 ]2+ (g). TBMBP and 33
  39. 39. TBEBP also show similar substitution ability. Information on the interaction between ligands and uranyl can be obtained by IR spectra (Fig.3). In [UO 2 (NO 3 ) 2 (TEMBP)], the P=O group is coordinated to the uranyl thus its stretching band shifts to lower wavenumbers. With excess of TEMBP added, the band due to free P=O group (1258 cm-1) -1 appears. The ligand substitution is evidenced by the decrease of intensity of band at 1525 cm , which is the υ(NO) stretching band of coordinated NO 3 - (in bidentate mode) [4]. In the case of TBP as ligand, the υ(NO) band almost does not change with increasing TBP concentration. Fig.4 UV-vis spectra of [UO 2 (TBMBP) 2 ]2+ (a) and uranyl extracted by 0.1M TBMBP /[BMI][NTf 2 ]. Aqueous HNO 3 solutions are (b) = 0.01M, (c) = 1M, and (d) = 6M. Initial uranyl concentration in the aqueous solutions is 0.01M. Fig.3. ATR-FTIR spectra of uranyl nitrate with 1, 3 and 10 eq. of TEMBP in [BMI][NTf 2 ] in the υ(P=O) (left) and υ(NO) region (right). The insert graph shows spectra of uranyl nitrate with various amount of TBP in the υ(NO) region. Unlike the TBP/IL system, extraction of uranyl by TBMBP/[BMI][NTf 2 ] is less dependent on the aqueous HNO 3 concentration. With 0.1M TBMBP/[BMI][NTf 2 ], almost 100% of the uranyl is extracted, while the acid concentrations ranging from 0.01M to 6M. Spectra of the IL phase after extraction are showing in Fig.4, and are all similar with the spectrum of [UO 2 (TBMBP) 2 ]2+, suggesting that extraction of uranyl by TBMBP via a single mechanism independent on HNO 3 concentration. The ability to substitute coordinated NO 3 , and the HNO 3 -independent extraction mechanism, indicate that neutral bidentate ligands have enhanced coordinating ability to uranyl versus their monodentate analogs such as TBP. The high efficiency and single mechanism of extraction in ionic liquids make them potential better alternatives for TBP. [1] I. Billard, A. Quadi, and C. Gaillard. Anal. Bioanal. Chem., 400, 1555 (2011). [2] Y. Liu, T. Chu, and X. Wang. Inorg. Chem., 52, 848 (2013). [3] Y. Wang . Studies on the Optical Spectra and Electrochemistry of Uranyl Complexes in Ionic Liquids. Master’s Thesis, Peking Universtiy, 2013. [4] K. Nakamoto. Infrared and Raman Spectra of Inorganic and Coordination Compounds, Theory and Applications in Inorganic Chemistry. Wiley-Interscience. 2009 34
  40. 40. Session 3: Waste Management 35

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