Some Hot Issues on Nuclear Energy Chemistry in China
Nuclear Energy Chemistry Group, Key Laboratory of Nuclear Analytical Techniques
Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049,
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.
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).
1. WQ Shi, YL Zhao, ZF Chai. Radiochim Acta. 2012, 100: 529.
Present status of nuclear in Japan after the accident of Fukushima Daiichi
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
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
Many inhabitants within the area of 30km of Fukushima Daiichi nuclear power plants are
Present status of nuclear in Japan after the accident of Fukushima Daiichi is introduced in this
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
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.
General Issues on Nuclear
Energy and Fuel Cycle
ENVISION OF WORLD NUCLEAR ENERGY /FUEL CYCLE DEVELOPMENT
AND CHINA’s ACTION
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
The Role of Advanced Reprocessing Technology on 3S (Safety, Security, and
Safeguards) in Nuclear Fuel Cycle and Radioactive Waste management
Jor-Shan CHOI 1
UC Berkeley Nuclear Research Center, University of California at Berkeley, CA, USA,
Email: email@example.com, firstname.lastname@example.org
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.
Flexible Fuel Cycle Initiative to Cope with the Uncertainties
after Fukushima Daiichi NPP Accident
Hitachi-GE Nuclear Energy, Ltd.
3-1-1 Saiwai, Hitachi, Ibaraki, 317-0073 Japan, Tel: +81-294-55-4319, Fax: +81-294-55-9904
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 . 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 . 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
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.
 Atomic Energy Commission of Japan, “Framework for Nuclear Energy Policy”, October 11, 2005.
 T. Fukasawa, et al., “Flexible LWR-to-FBR Transition Fuel Cycle System”, Proc. GLOBAL 2011,
No. 355737, Makuhari, Japan, December 11-16, 2011.
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
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
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
Nuclear Fuel Cycle Process Development Division, Korea Atomic Energy Research Institute, 1045
Daedukdaero, Yuseong, Daejeon 305-353, Republic of Korea
* Corresponding author: email@example.com, firstname.lastname@example.org
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)
The Nuclear Education and Training Program at University of California Irvine
Mikael Nilsson1*, George Miller2, A.J. Shaka2
Department of Chemical Engineering and Materials Science,
Department of Chemistry,
University of California Irvine, Irvine, CA 92697-2575
* Corresponding author: email@example.com
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  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 , 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.
. V.P. Guinn, G.E. Miller, F.S. Rowland. Radiochemistry teaching and research at UC Irvine, Nucl.
Technol., 27, 1, 124, (1975).
. http://nssc.berkeley.edu/ (Accessed Oct 14, 2013)
Basic Chemistry of Actinides
and Fission Products
Utilization of Technetium and Actinide Compound Synthesis and Coordination
Chemistry for the Nuclear Fuel Cycle: Exploring Separations, Fuels, and Waste
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,
Radiochemistry Program, University of Nevada, Las Vegas, Las Vegas, Nevada, USA
Energy Engineering and Systems Analysis Directorate, Argonne National Laboratory
* Corresponding author: firstname.lastname@example.org
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  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 .
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
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
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,
4. Pemberton, W.J., Droessler, J.E., Kinyanjui, J.M., Czerwinski, K.R., Hatchett, D.W. Electrochim
Acta., 93, 264-271 (2013).
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.
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.N. Frumkin Institute of Physical Chemistry and Electrochemistry RAS
31, Leninsky prospekt, Moscow, 119071, Russia. * - email@example.com
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 () 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
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 . 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
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  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.
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,
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.
DFT Study on a Trivalent Uranium Complex Promoted Functionalization of
Carbon Dioxide and Carbon Disulfide
Dongqi Wang1,*, Zhifang Chai1, Wanjian Ding2, Weihai Fang2
CAS Key Laboratory of Nuclear Radiation and Nuclear Energy Techniques, Institute of
High Energy Physics, Chinese Academy of Sciences, Beijing, 100049
College of Chemistry, Beijing Normal University, Beijing, 100875
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
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.
 E. M. Matson, W. P. Forrest, P. E. Fanwick, S. C. Bart, J. Am. Chem. Soc. 2011, 133: 4948.
 W. Ding, W. Fang, Z. Chai, D. Wang, J. Chem. Theory Comput. 2012, 8, 3605-3617.
Using Phosphonates to Probe Structural Differences Between the
Transuranium Elements and Their Proposed Surrogates
Juan Diwua,*, Thomas E. Albrecht-Schmittb
School of Radiation Medicine and Protection (SRMP) and School of Radiological and
Interdisciplinary Sciences (RAD-X), Soochow University, Suzhou, Jiangsu 215123, China
Department of Chemistry and Biochemistry, Florida State University, 102 Varsity Way,
Tallahassee, Florida 32306-4390, USA
* Corresponding author: firstname.lastname@example.org
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
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
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.
J. Diwu and T. E. Albrecht-Schmitt, in Metal Phosphonates, chapter 19, transuranium
phosphonates (Eds: Abraham Clearfield, and Konstantinos Demadis), RSC Publishing,
From Thorium to Curium: Unprecedented Structures and Properties in Actinide
Shuao Wanga,*, Evgeny V. Alekseevb, Thomas E. Albrecht-Schmittc
School of Radiation Medicine and Protection (SRMP) and School of Radiological and
Interdisciplinary Sciences (RAD-X), Soochow University, Suzhou, Jiangsu 215123, China
Institute for Energy and Climate Research (IEK-6), Forschungszentrum Jülich GmbH,
52428 Jülich, Germany
Department of Chemistry and Biochemistry, Florida State University, 102 Varsity Way,
Tallahassee, Florida 32306-4390, USA
* Corresponding author: email@example.com
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. 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.
 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
 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,
 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
 S. Wang, E. V. Alekseev, W. Depmeier, T. E. Albrecht-Schmitt, Chem. Commun., 2011,
 S. Wang, E. V. Alekseev, J. Ling, G. Liu, W. Depmeier, T. E. Albrecht-Schmitt, Chem.
Mater., 2010, 22, 2155-2163
 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
 S. Wang, E. V. Alekseev, W. Depmeier, T. E. Albrecht-Schmitt, Chem. Commun., 2010,
 S. Wang, E. V. Alekseev, W. Depmeier, T. E. Albrecht-Schmitt, Inorg. Chem., 2011, 50,
 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
 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
 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
Fig. 2.The synthesis schemes of trivalent actinide borate compounds and the photo
showing the product crystals
Diamides of Dipicolinic Acid in Complexation and Separation of Selected Metals
Alena Paulenovaa*, Joseph Lapkaa, Vasiliy Babainb, Mikhaliy Alyapyshevb, Jack D. Lawc
Oregon State University, Corvallis, OR, USA
Khlopin Radium Institute, St Petersburg, Russia
Idaho National Laboratory, Idaho Falls, ID, USA
* Corresponding author: firstname.lastname@example.org.
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). 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.
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.
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
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
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 :
M3+ + xHCCD M(CCD)x(3-x)+
The overall sum of these two equations can then be written as:
M3+ + (3-x)NO3ˉ + xHCCD
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. 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.
 Serrano-Purroy, D.; Baron, P.; Christiansen, B.; Glatz, J. P.; Madic, C.; Malmbeck, R.; Modolo, G.. Sep.
Purif. Technol., 45, (3) 157-162 (2005)
 Zhu, Z. X.; Sasaki, Y.; Suzuki, H.; Suzuki, S.; KIMURA, T. Anal. Chim. Acta., 527, (2) 163-168
 Modolo, G.; Asp, H.; Schreinemachers, C.; Vijgen, H. Solv. Extr. Ion Exch., 25, (6) 703-721 (2007)
 BABAIN, V.A.; ALYAPYSHEV, M.YU.; SMIRNOV, I.V.; SHADRIN, A.YU.. Radiochemistry, 48, (4)
 Paulenova, A.; Alyapyshev, M.Yu.; Babain, V.A.; Herbst, R.S.; Law, J.D. Sep. Sci. Technol., 43, (9)
 J. Rais, B. Grü Ion Exchange and Solvent Extraction, A Series of Advances, 17, 243-334, by Y. Marcus, A.
K. SenGupta, CRC Press, (2004).
 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
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: email@example.com
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.
 R. Sellin and S. D. Alexandratos, Ind. Eng. Chem. Res. 52, 11792 (2013).
 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).
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*
Division of Nuclear Materials Science and Engineering, Shanghai Institute of Applied
Physics,Chinese Academy of Sciences, Shanghai 201800, China
Department of Chemistry, Tsinghua University, Beijing 100084, China
Department of Chemistry, Brown University, Providence RI 02912, USA
* Corresponding author: firstname.lastname@example.org (J.S.); email@example.com (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.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)
 C. Le Brun, J. Nucl. Mater. 360, 1 (2007).
 Y.H. Cho, T.J. Kim, S.E. Bae, Y.J. Park, H.J. Ahn and K. Song, Microchem. J. 96, 344 (2010).
 M. Salanne, C. Simon, P. Turq, R.J. Heaton, P.A. Madden, J. Phys. Chem. B 110, 11461 (2006)
 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)
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).
First-principles calculation of intrinsic and defective properties of UO2 and ThO2
Han Hana, Cheng Chenga and Ping Huaia*
Key Laboratory of Nuclear Radiation and Nuclear Energy Technology, Shanghai
Institute of Applied Physics, Chinese Academy of Sciences, Shanghai, China 201800
*Corresponding author: firstname.lastname@example.org
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.
 G. Schreckenbach, G. Shamov, Acc. Chem. Res. 43, 19 (2010).
 Kevin T. Moore, Rev. Mol. Phys. 81, 235-298 (2009).
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)
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 , 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.
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
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
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.
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
Function: y=a/(1+exp(k*(x-x 0 )))
Function: y=a*exp(-exp(-k*(x-x 0 )))
 Fang LIU, Master's Thesis of CIAE, 2009
 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.
 J. Garraway, Journal of the Less Common Metals, Volume 97, February 1984, pp. 191–203.
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: email@example.com.
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  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 .
According to previous reports , 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+.
 Handbook of Hazardous Materials (Ed: M. D. Corn), Academic Press, San Diego 1993.
 A. Safavi, M. Sadeghi, Anal. Chim. Acta, 567, 184-188, (2006).
 F. S. Rojas, C. B. Ojeda, Anal. Chim. Acta, 635, 22-44, (2009).
 V. Thomsen, D. Schatzlein, D. Mercuro, 18, 112-114, (2003).
 H. A. Benesi,; J. H. Hildebrand, J. Am. Chem. Soc. 71, 2703-2707, (1949).
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: firstname.lastname@example.org
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 . 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.
 J. H. Lan, W. Q. Shi, Z. F. Chai , et al., Coord. Chem. Rev., 256, 1406 (2012).
 M. J. Hudson, L. M. Harwood, D. M. Laventine, et al., Inorg. Chem., 52, 3414 (2013).
 C. Z. Wang, J. H. Lan, W. Q. Shi, et al., Inorg. Chem., 52, 196 (2013).
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).
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: email@example.com
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
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 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, electrodeposition 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 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
(a) Species of Am(III)
(b) Species of Cm(III)
Fig.1. Speciation distribution of Am(III) as function of pH in aqueous solution
 Y. Sasaki, Y, Kitatsuji, Y. Tsubata, Y. Sugo, Y. Morita, Solvent. Extr. Res. Dsv. 18, 93(2011).
 K. Binnemans, Chem. Rev, 107, 2592(2007).
 S. Liu, Atomic. Ene. Sci. Technol. 22, 238(1988)
 K. Marmoru, F. Tetso, K. Fumio, J. Nucl. Sci. Technol. 35, 185(1998).
Burn-up calculation of plutonium in fusion-fission hybrid reactor
Kento Fukanoa*, Shunji Tsuji-Iioa, Hiroaki Tsutsuia, Yoji Someyab
Tokyo Institute of Technology
Japan Atomic Energy Agency
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.
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
[UO2(NO3)4]2- Complex in Ionic Liquids Investigated by Optical Spectroscopic and
Yupeng Liu, Taiwei Chu*
Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular
Engineering, Peking University, Beijing 100871, China.
* Corresponding author: firstname.lastname@example.org.
The tetranitratouranium(VI) complex, [UO2(NO3)4]2-, is thought to be unstable in common
molecular solvents. Recently, C. Gaillard et al.  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]- . 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.
* Nitromethane as solvent, from Ref..
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.
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
* 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.
 C. Gaillard, O. Klimchuk, A. Quadi, I. Billard and C. Hennig. Dalton Trans., 41, 5476 (2012)
 K. Servaes, C. Hennig, I. Billard, C. Gaillard, K. Binnemans, C. Gorller-Walrand, and R. Van
Deun. Eur. J. Inorg. Chem., 2007, 5120 (2007)
 J. L. Ryan. J. Phys. Chem., 65, 1099 (1961)
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: email@example.com.
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 . 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 .The
optical spectra and electrochemistry of uranyl complexes of some monodentate organophosphorus
ligands have also been studied by our group . 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
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)
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) . 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
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)
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
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.
 I. Billard, A. Quadi, and C. Gaillard. Anal. Bioanal. Chem., 400, 1555 (2011).
 Y. Liu, T. Chu, and X. Wang. Inorg. Chem., 52, 848 (2013).
 Y. Wang . Studies on the Optical Spectra and Electrochemistry of Uranyl Complexes in Ionic
Liquids. Master’s Thesis, Peking Universtiy, 2013.
 K. Nakamoto. Infrared and Raman Spectra of Inorganic and Coordination Compounds,
Theory and Applications in Inorganic Chemistry. Wiley-Interscience. 2009