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Los Alamos National Laboratory, Mail Stop G-756, Los Alamos, NM Covalency, or the simple sharing of electrons between elements to form chemical bonds, is a fun damental concept in chemistry that pervades our fundamental descriptions of chemical bonding in s-, p-, and d-block elements of the periodic table. Despite decades of study, whether the correspond ing f-block elements participate in covalent bonding is still unclear, and unraveling the nature of bonding in f-element systems remains a computational and experimental challenge. We have employed Cl K-edge x-ray absorption spectroscopy on a series of simple octahedral uranium and lanthanide chloride salts, MCl6n in order to assess the relative roles of the valence f and d orbitals in these systems, and compare the covalent contributions to bonding between isostructural actinide and lanthanide pairs. Chlorine K-edge x-ray absorption spectroscopy on UCl6 systems indicates that there are covalent interactions between Cl 3p and U 6d orbitals, with no participation from uranium 5f orbi 2 3 tals. A comparison of the normalized Cl K-edge spectra for UCl6, UCl6, and UCl6 is shown in Fig 1. The n UCl6 anions show two distinct pre-edge features that show clear differences in intensity as a function of oxidation state, with U(V) U(IV) U(III). The predominant covalent interactions are expected to oc cur through UCl - and -bonding via t2g and eg interactions with U 6d orbitals.2 For the Cl K-edge data therefore, we expect bound state transitions from Cl 1s eg (*) and t2g (*) orbitals. Qualitatively, the Cl K-edge data fulfills these expectations.

The intensity of a ligand pre-edge peak is the in tensity of a ligand-centered 1s3p transition weighted by the covalent character of the ligand 3p orbitals in the antibonding molecular orbitals of primarily 5f or 6d character. The pre-edge intensi ties will be proportional to the percent character of ligand p contribution to *.3 Pre-edge and rising edge features can be modeled by pseudo-Voigt line shapes from which the Cl 3p character per MCl bond was determined for UCl6n and LnCl6n com plexes. These preliminary studies, reproduced dur ing two separate experimental runs, using two sepa Fig. 1. A comparison of Cl K-edge XAS rate encapsulation approaches, and two different data on the UCl6n series of com detector types establishes that we can observe pre pounds where the oxidation state edge features in light actinide complexes, that we an varies from U(V) to U(III). Data in extract the percent covalency from these data, and red, fit in blue. The Cl 1s transitions that we can successfully encapsulate actinides for are assigned to the U 6d t2g and eg transuranic studies. These and other data comparing orbitals, as noted in the figure.

octahedral lanthanide and transition metal MCl6n ions will be presented.

References 1. Choppin, G. R., Covalency in f-element bonds. Journal of Alloys and Compounds 2002, 344, (1-2), 55-59.

2. Kaltsoyannis, N.;

Hay, P. J.;

Li, J.;

Blaudeau, J.-P.;

Bursten, B. E., Chapter 17 Theoretical Studies of the Electronic Structure of Compounds of the Actinide Elements. In The Chemistry of the Actinide and Transactinide Elements, Morss, L. R.;

Edelstein, N. M.;

Fuger, J., Eds. Springer: 2006;

pp 1893-2012.

3. Solomon, E. I.;

Hedman, B.;

Hodgson, K. O.;

Dey, A.;

Szilagyi, R. K., Ligand K-edge X-ray absorption spectros copy: covalency of ligand-metal bonds. Coordination Chemistry Reviews 2005, 249, (1-2), 97-129.


Federal State Unitary Enterprise "State Scienitific Center of RF Research Institute of Atomic Reactors", Dimitrovgrad-10, Ulyanovsk region, Russia, 433510, E-mail: adm@niiar.ru, bav@niiar.ru, Web site: http//www.niiar.ru The technology of SNF management in molten salts currently developed by a group of institutes headed by RIAR has had several stages of development:

basic research of uranium, plutonium and main FP properties;

development of the equipment and implementation of the pyroelectrochemical technology of granulated U-Pu fuel production, development of the vibropacking method and in-pile testing of vibropacked fuel pins with granulated fuel;

development of closed fuel cycle elements. Checking of the technology using batches of SNF.

In-pile tests. Feasibility study of the closed fuel cycle (CFC). Study of application of the tech nology to other objects (transmutation;

nitride, cermet and other fuels).

The current status of the research is the following:

Basic research. Properties of uranium, plutonium, thorium, and neptunium in chloride melts have been studied in much detail. The data on physical chemistry and electrochemistry of the main FP is enough for understanding the processes. Detailed studies of americium, curium, and technetium chemistry are the essential investigation directions.

Engineering development. The technology and equipment bases have been developed for the processes of oxide fuel reprocessing and fabrication. The technology was checked using kg of pure fuel from different reactors and 20 kg of irradiated BN-350 and BOR-60 fuel. The bases of the technology have been provided and the feasibility study has been carried out for a full-scale plant of BN-800 CFC.

Industrial application: Since the technology is highly prepared, the activities on industrial ap plication of U-Pu fuel are now underway. The BOR-60 reactor uses fuel obtained by the dry method, the design of the facility for implementation of CFC reactors is being devel oped.Experimental FAs have been tested in the BN-600 reactor. The facilities for production of U-Pu fuel of the BN-600 hybrid core are being modernized.

Apart from the main technology of oxide fuel reprocessing and production, new dry processes are being studied:

obtaining of oxide fuel with neptunium and americium for transmutation;

reprocessing of nitride fuel (for the BREST closed fuel cycle);

reprocessing of uranium fuel from research reactors (in order to solve the problem of uncon ventional SNF management);

metallization of oxide fuel for long-term storage.


Department of Chemistry and Biochemistry, Florida State University, Tallahassee, FL, 32306-4390, Fax: 850-644-8281, Choppin@chem.fsu.edu Although nuclear and radiochemistry cab can be considered mature branches of chemistry one hun dred years after the discovery of radioactivity, challenges abounds for chemists in many areas in nuclear science. Global interest in nuclear and radiochemistry encompasses a wide range of difficult tasks, including the remediation of contaminated nuclear facilities, limiting nuclear proliferation, providing clean and efficient power for the developed and developing world, the diagnosis and treatment of disease, and the advancement of biological, physical and earth sciences. With the in creased understanding of the Greenhouse Gas Problems the need for abundant, clean nuclear en ergy is becoming recognized as more of a necessity internationally. Education in nuclear and radio chemistry is vital to the success of these endeavors. The present status of nuclear education interna tionally is reviewed and the necessary future developments are discussed.


Institut de Chimie Molculaire de lUniversit de Bourgogne (ICMUB) (UMR 5260), Facult des Sciences Mirande, 9, avenue Alain Savary BP 47870, 21078 DIJON Cedex, France, Roger.Guilard@u-bourgogne.fr There is a continous need to develop new separation techniques able to selectively extract metal ions from dilute waste waters containing U, Pu, and Am. Innovative technologies imply also com prehensive research studies of the phenomena dealing with actinides especially for optimising the use of uranium and plutonium. Our strategy relies on solid-liquid extraction using chelating agents grafted on a hydrophilic support. Moreover, cyclic tetraamines such cyclam and cyclen derivatives and polyaminocarboxylic ligands are chelating agents which present a strong affinity towards tran sition and non transition metallic cations.

We have described the synthesis and the characterization of tetraazamacrocycle-bound silica gels which have been used for the treatment of alpha contaminated (U, Pu, Am) liquid wastes1,2. We will review the synthesis, the structural study and the efficiency of these sequestrating ligands. As part of our ongoing actinide chelation studies we have revisited the complexation equilibria of pluto nium(IV) with a polyaminocarboxylic sequestrating agent.

References 1. H. Chollet, J.L. Babouhot, F. Barbette, R. Guilard, WO 0115806 (2001).

2. F. Barbette, F. Rascalou, H. Chollet, JL. Babouhot, F. Denat, R. Guilard, Anal. Chim. Acta 502 (2004) 179.

3. M. Meyer, R. Burgat, S. Faure, B. Batifol, J.-C. Hubinois, H. Chollet, R. Guilard, C.R. Acad Sci. (in press).

VIII , , 2007 ACTINIDE CONTAINING NANOPARTICLES FORMATION, MIGRATION IN THE ENVIRONMENT AND METHODS OF EXAMINATION Kalmykov St.N.ab, Novikov A.P.b, Myasoedov B.F.b, Batuk O.N.a a Chemistry dept. of Lomonosov Moscow State University, Leninskie Gory, Moscow 119992, Russia, b Vernadsky Institute of Geochemistry and Analytical Chemistry RAS, Moscow 119991, Russia The knowledge on the speciation of radionuclides is required for the development of simple and cost-effective remediation actions at the territories contaminated by radionuclides as well as for de sign of barrier system at the nuclear waste repository sites. The experimental data indicate that the migration behavior of low-soluble radionuclides, e.g. tetravalent actinides and Tc(IV) is defined by the presence of different colloidal particles including those of nanometer size. The formation of such nanoparticles could occur upon interaction of groundwater on the spent nuclear fuel (SNF) or nuclear waste forms as well as by sorption of radionuclides onto natural aquatic colloids.

The mechanisms of formations of intrinsic colloids upon corrosion of UO2 at different tempera tures are discussed. It was established by XRD, XPS, XANES, EXAFS, SEM and HR-TEM that depending on the temperature the competition is established between bulk oxidation and formation of secondary phases including those of nanosize containing U(VI). The mechanisms of radionuclide sorption onto colloids of UO2+x and the role of redox reactions on the surface are discussed.

In order to use XANES and EXAFS for analysis and in-situ examination of actinide nanoparti cles the model U(VI) and Th(IV) oxide nanoparticles were synthesized by incorporation into pore structure of SiO2 (MCM-41 family). This enables to prepare monodispersed crystalline and amor phous nanoparticles of 3 and 2 nm. It was demonstrated that the white line intensity in XANES spectra depends on the particle size and is defined by the density of states. Using XANES and EXAFS the connection between spectral properties of nanoparticles with their size and degree of surface oxidation was established in the row UO2 UO2.25.

The data obtained in the well defined laboratory conditions were supported by analysis of groundwater and colloidal matter samples collected in different geochemical conditions (pH and Eh). Under oxidizing conditions (Eh +100 mV) the formation of so-called pseudo-colloids occur upon sorption of actinides onto different aquatic colloids. The nano-SIMS was used to study that Pu and U are preferentially bound to nanoparticles of amorphous Fe(III) oxyhydroxide and MnO2, while other colloidal particles did not sorb radionuclides. Under reducing conditions (Eh - mV) the intrinsic hydroxocolloids are formed that bound other radionuclides.

2452 VIII , , NEW PERSPECTIVES ON MICROPOROUS AND NANOTUBULAR URANIUM COMPOUNDS Krivovichev S.V.a, Alekseev E.V.b, Depmeier W.c, Tananaev I.G.d, Myasoedov B.F.d a St.Petersburg State University, University Emb. 7/9, 199034 St.Petersburg, Russia b Nizhny Novgorod State University, 603950 Nizhny Novgorod, Russia c Institut fuer Geowissenschaften, Universitaet Kiel, D-24118 Kiel, Germany d A.

N. Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences, Leninsky pr. 31, Moscow, 119991, Russia Microporous and nanostructured actinide compounds are of great interest due to their formation during alteration of spent nuclear fuel and their potential applications in nuclear industry and radio chemistry. Synthesis of these compounds usually involves addition of organic templates such as amines with different shape and composition13. Recently, we succeeded in preparation of new mi croporous and nanotubular compounds using 18-crown-6-ether complexes of the H3O+ hydronium ions as templates. Yellow transparent crystals of (H3O)8[(H3O)@(18-crown 6)]2[(UO2)14(SO4)19(H2O)4](H2O)20.5 (1) and (H3O)2K-[(H3O)@(18-crown 6)][(UO2)3(SeO4)5](H2O)4 (2) have been obtained by evaporation from aqueous solutions of uranyl nitrate, 18-crown-6-ether and sulfuric or selenic acid. The structures of both compounds contain U6+ cations that form uranyl [O=U=O]2+ ions coordinated by five additional O atoms in their equatorial planes. The resulting UO7 pentagonal bipyramids share corners with [TO4]2- tetrahedral oxoanions (T = S, Se) to produce unique and highly porous structural units.

The structure of 1 contains exceptionally complex [(UO2)14(SO4)19(H2O)4]10- microporous framework with a low framework density (FD) of 8.5 M atoms per 1000 3 (here M is a frame work-forming cation, i.e. U and S). The framework has large cross-shaped channels running parallel to the c axis and occupied by the water molecules and [(H3O)@(18-crown-6)]+ complexes. The channels have absolute dimensions 8.88.8 2 that results in the crystallographic free dimensions of 6.16.1 2. As far as we know, this is the maximal porosity ever observed for an actinide-based mi croporous framework structure. The structure of 2 consists of the [(UO2)3(SeO4)5]4- uranyl selenate nanotubules extended along the a axis and identical to those found in K5[(UO2)3(SeO4)5](NO3)(H2O)3.5 (3).1 However, in contrast to the structure of 3, where tubules are packed according to the hexagonal packing of rods, in the structure of 2, tubules form tetragonal packing as they are separated by columns of disordered [(H3O)@(18-crown-6)]+ complexes.

In conclusion, syntheses and characterization of 1 and 2 demonstrates new possibilities of engi neering novel microporous and nanotubular actinide topologies by using large organic cations such as the crown ether complexes of the H3O+ hydronium ion.

This work was supported by the Russian Ministry of Science and Education (grants RNP and MD 4886.2007.5), RFBR (06-03-32096) and Alexander von Humboldt Foundation.

References 1. S.V. Krivovichev, V. Kahlenberg, R. Kaindl, E. Mersdorf, I.G. Tananaev, B.F. Myasoedov, Angew. Chem. Int. Ed.

2005, 44, 1134.

2. S.V. Krivovichev, V. Kahlenberg, R. Kaindl, E. Mersdorf, I.G. Tananaev, B.F. Myasoedov, J. Amer. Chem. Soc.

2005, 127, 1072.

3. S.V. Krivovichev, P.C. Burns, I.G. Tananaev, eds. Structural Chemistry of Inorganic Actinide Compounds. Elsevier 2007.

VIII , , 2007 AMERICIUM IN THE FINNISH ENVIRONMENT Lehto J.a, Salminen S.a, Jaakkola T.a, Lusa M.a, Leskinen A.a, Paatero J.b a Laboratory of Radiochemistry, University of Helsinki, Finland b Finnish Meteorological Institute, Helsinki, Finland The deposition of 241Am in Finland from the Chernobyl accident was 3.71010 Bq which was 0.8% of the total 241Am released in the accident. The amount of 241Am from the Chernobyl accident is, however, only 1.7% on the total deposition, the remaining 98.3% originating from the nuclear weapons test fallout from 1950ies to 1970ies. Unlike nuclear weapons test fallout, the Chernobyl fallout distributed spatially very unevenly (Fig. 1).1 Highest deposition occurred in a sector from the southwestern coast to northeast, the fallout pattern resembling the behavior of other refractory ra dionuclides, such as plutonium isotopes, 95Zr and 141Ce. The deposition varied in a wide range of 0.012 Bq/m2 to 9.3 Bq/m2 while the nuclear weapons test fallout was in average 6 Bq/m2. Thus in the most contaminated areas the Chernobyl accident forms the major americium constituent in the environment. In the nuclear weapons test fallout the 241Am/239,240Pu ratio in Finland was about 0.1.

In the Chernobyl fallout this ratio was initially somewhat higher, about 0.3. Due to high deposition of 241Pu, the mother isotope of 241Am, the amount of 241Am is still increasing and the Am/239,240Pu ratio, from the Chernobyl fallout, will increase to a maximum value of 2.8 by 2060. 7 2 oN Am-241 (Bq/m 2) 0.0363 6 9 oN 0. 6 6 oN 6 3 oN 6 0 oN 20oE o 24oE o 32 E 28 E Fig. 1. Spatial distribution of 241Am deposition in Finland from the Chernobyl fallout.

Am in forest soil, originating from the nuclear weapons test fallout, and its transfer into ber ries in the Northern Finland has been studied. The results show that most of 241Am in soil columns is located in the organic layer at the depth of 2-3 centimeters. The transfer factors from soil into ber ries are very low, between 0.0001 and 0.0005 m2/kg.

Am in the sediments and water of the Lake Pijnne, the water source of the Helsinki metro politan area, has been studied. The maximum concentration of 241Am in the sediments has been found at the depth of 5-7 centimeters.

References 1. S.Salminen, J.Paatero, T.Jaakkola and J.Lehto, Americium and Curium Deposition in Finland from the Chernobyl Accident, Radiochimica Acta 93(2005)771.

2. J.Paatero and T.Jaakkola, Determination of the 241Pu Deposition in Finland After the Chernobyl Accident, Radio chimica Acta 64(1994)139.


Chemistry department of Lomonosov Moscow State University, Moscow 119992, Russia Radionuclide sorption phenomenon is widely used in radiochemical practice and defines their mi gration behavior in the environment. Therefore the sorption of radionuclides is extensively studied in the content of sorption processes during possible accidents at the NPPs, upon medical treatment using radionuclides and their migration from nuclear waste disposal sites. The accumulated experi mental data and observation of environmental processes indicate that sorption is proceeding through several steps. First molecules or ions of sorbate are forming single bonding with sorbent surface then they migrate to the pre-surface layer and then migrating to the bulk volume of the sorbent.

Most of the natural and man-made sorbents have multilayer hierarchical structures so that the vol ume of single separate particles (crystalline or amorphous) is not uniform in terms of sorption. As a result the diffusion of radionuclides to the bulk volume of the sorbent is a multi-step process.

The sorption at different steps is affected by radiation defects originating from decay of radionu clides in different manner. Radiation effects could cause swelling of sorbent particles, increase of diffusion to the bulk volume, increase of the solubility of sorbent particles in case of they are not emplaced into the saturated solution and radiation dispersion of the particles. The sorbent could be also modified due to the accumulation of the decay products.

The intensity of all these processes depends on the size and shape of the sorbent particles. The size (R) of the particles is normally not uniform and therefore the sorption is sensitive towards dis tribution function (R) of particles according to their sizes. The mathematical modeling demon strate that even for small radiation defects the transition from monodispersed sorbent to the polydespersed one (without changing of the average particle size) increase the time of 95% sorption (0,95) by one order of magnitude. Upon further increase of radiation doze the 0,95 is decreased in different manner for samples with different distribution of (R). This effect is very important for environmental processes for which (R) is broad as well as for man-made colloidal suspensions and aerosols for which (R) is narrow.

As it was demonstrated in experimental investigations and by mathematical modeling, sorption in colloidal suspensions and aerosols is very sensitive towards chemical and structural heterogene ity of sorbents. It is clear that one of the main ways of radionuclide spreading in environmental and industrial conditions is their migration with colloids and aerosols that could sorb radionuclides.

Therefore the studies of sorption onto highly dispersed sorbents are very important.

These effects and phenomena are described only at semiquantitative level due to the absence of sensitive experimental data. The accumulation of such data is an important task of modern radio chemistry.

The current work was supported by RBRF (project 05-03-33028a) VIII , , 2007 PROSPECTIVES ON ACTINIDE ADVANCED MATERIALS OBTAINED BY MOLECULAR REACTIVITY Meyer D.J.M.a, Garcia J.b, Wong Chi Man M.c, Moreau J.c, Fouchard S.d, Hilaire S.b, Gouder Th.e, Wastin F.e, Colineau E.e, Rebizant J.e, Guillaneux D.b, Zemb Th.a a CEA ICSM, UMR 5257, BP 17171 Bagnol/Ceze France b CEA-DEN/DRCP/SCPS/LCAM, BP 17171 Bagnol/Ceze France c ENSCM, rue de lcole Normale, Montpellier France d IRSN, France e ITU, Forschungszentrum, Karlsruhe Germany This presentation will be focused on the approach that will be developed at the Institut de Chimie Sparative de Marcoule in the actinide group (Laboratory of Chemistry and Physical-Chemistry of the Actinides).

Main goal is to use the reactivity of several actinide molecular species in solution to obtain original materials. The methods considered are based on the recent silica and silicon hybrid material science using supramolecular assembling for materials properties tuning. To reach this aim, mo lecular reactivity needs to be studied first, especially electronic and geometric structures in correla tion with the reactivity of the related actinide species. In a second step, this reactivity will be im plemented in complex fluids to obtain original actinide materials.

In this frame, we will first expose some fundamental consideration about uranium (VI) and nep tunium (V, VI) electronic structure resulting from Raman and photoelectron spectroscopy studies as well as from the magnetism investigations on some neptunium compounds. Main interest was fo cused on the charge at the metal core and the relation between axial and equatorial interactions on the acinyl moiety. In a second step, we will present the initial results of the controlled synthesis of mixed silicon-actinide carbides using molecular engineering. The resulting material can be consid ered as potentially organized at a multiscale level.

2456 VIII , , MODERN TRENDS IN RADIOACTIVE WASTES PARTITIONING TECHNOLOGIES Romanovsky V.N., Babain V.A., Smirnov I.V., Myasoedov B.F.b, Tananaev I.G.b, Rovny S.I.c Khlopin Radium Institute,28, 2nd Murinsky av., St-Petersburg, Russia, b Vernadsky Institute of Geochemistry and Analytical Chemistry, Moscow c PA Mayak, Ozyersk, Russia Localization of long lived radionuclides to the stable matrices is the main demand to the radioactive waste processing technologies in closed nuclear fuel cycle. Its needed to remove and separate radionuclides for such matrices obtaining. Most of modern partitioning flowsheets are extraction ones.

There are a lot of new extraction systems which proposed for long lived radionuclides removing and separation. Simultaneous extraction of several radionuclides in one extraction cycle and solvents for such extraction is very promising. Research in this direction is actively going in USA, Russia, Japan, European Council.

Flowsheets for cesium and strontium separation on the base of cobalt dicarbollide, crown ethers, calixarenes and mixtures of these compounds in different diluents were proposed and studied.

Diamides of carbonic acids malonic, diglycolic, dipicolinic were actively studied as extractants for minor actinides in hydrocarbon and fluorinated diluents. Some processed were proposed and tested.

Great interest was shown to separation of technetium. It was result of change in priorities in fuel reprocessing. Advantages and drawbacks of different flowsheets from technological and economical point of view are compared and discussed in the presentation.

VIII , , 2007 PERSPECTIVE TECHNOLOGIES FOR SNF REPROCESSING AT THE PILOT DEMONSTRATION CENTER Romanovsky V.N.a, Myasoedov B.F.b, Fedorov Yu.S.a, Shadrin A.Yu.a a Khlopin Radium Institute, St.Petersburg b Vernadsky Institute of Geochemistry and Analytical Chemistry RAS, Moscow 119991, Russia The concept of the Federal Special Program Development of the Russian Atomic Energy Industrial Complex in 2007-2010 and its prospects up to 2015, approved by the Government of the Russian Federation, supposes intensive building of nuclear power plants (NPPs), that will inevitably cause further spent nuclear fuel (SNF) accumulation. In this connection design of a new generation re processing plant becomes urgent. This new plant must be protected against main disadvantages of RT-1 plant related with formation of liquid moderate-level and low-level wastes, which can pollute the environment. The program Design of the Pilot Demonstration Center (PDC) for SNF reproc essing based on innovation technologies was approved at the end of 2006. In the context of this program three main directions of the process flowsheet for SNF reprocessing are being developed:

simplified PUREX process is the hydrometallurgical process based on extraction with TBP solutions in diluent (KRI and MCC);

crystallization process is a hydrometallurgical process based on crystallization of nitrates at ambient temperature, (VNIINM);

fluid extraction is a hydrometallurgical process based on extraction with TBP solutions in su percritical and liquid carbon dioxide or freon (KRI, MCC, GEOChI RAS).

The presentation considers the key operations and main advantages and disadvantages of the technologies, being developed for the Pilot Demonstration Center.

2458 VIII , , SOFT X-RAY STUDIES OF ACTINIDE MATERIALS CHEMISTRY Shuh D.K.a, Tyliszczak T.b, Nico P.S.c, Dhn R.d a Actinide Chemistry Group, Chemical Sciences Division, Glenn T. Seaborg Center, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 USA (DKShuh@lbl.gov) b Advanced Light Source Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 USA c Earth Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 USA d Laboratory for Waste Management, Paul Scherrer Institute, 5232 Villigen PSI, Switzerland Soft x-ray spectromicroscopy utilizing the scanning transmission x-ray microscopy (STXM) at the Advanced Light Source-Molecular Environmental Science (ALS-MES) Beamline 11.0.2 has been utilized to investigate actinide materials, particulates, and actinide-related materials. The ALS-MES STXM utilizes near-edge x-ray absorption fine structure (NEXAFS) to obtain direct spectroscopic information from radioactive materials and is capable of imaging particles, both with a spatial reso lution of better than 25 nm. The ALS-MES STXM operates from 125 eV to 2150 eV. The extended energy range enables NEXAFS investigations of light elements frequently associated with envi ronmentally-relevant radioactive materials at their K-edges and to collect oxidation state informa tion from NEXAFS spectra measured at the actinide 4d core level thresholds (700 eV to 900 eV).

NEXAFS spectromicroscopy experiments related to the environmental science of radioactive materials have included investigations of actinide reference materials, biological systems, colloids, wasteform glasses, clays, and cements. Recent studies have begun to investigate the bonding char acteristics of simple and chelating ligands, as well as the resulting complexes with both lanthanides and actinides. These more complex experiments build on initial STXM NEXAFS studies of the light actinide oxides and experiments with actinide reference materials containing oxygen.1 To ad dress issues of complexation and separations from a more complete perspective, investigations at the N K-edge have been initiated to characterize nitrogen bonding in prototypical f-element materi als and in f-element complexes where the metal ion is coordinated by nitrogen. The NEXAFS spec tra obtained from the respective K-edges (C, N, O) for the suite of ligands and complexes investi gated are largely molecular in nature. This provides an opportunity to successfully simulate the spectra starting with chemically meaningful models, in addition to regular spectral assignments.

The capabilities of soft x-ray STXM spectromicroscopy for investigations of radioactive materi als continue to be developed. Although there are some limitations such as concentration, progress continues to be made. The development of the miniSTXM at LBNL will provide additional oppor tunities to utilize soft X-ray spectromicroscopy.

This work was supported by the Director, Office of Science, Office of Basic Energy Sciences, Division of Chemical Sciences, Geosciences, and Biosciences of the U.S. Department of Energy at Lawrence Berkeley National Laboratory under Contract No. DE-AC02-05CH11231.

References 1. H. J. Nilsson, T. Tyliszczak, R. E. Wilson, L. Werme, D. K. Shuh, J. Anal. Bioanal. Chem. 2005, 383, 41.

VIII , , 2007 EXTRACTION SEPARATION OF ACTINIDE AND RARE EARTH ELEMENTS BY CROWN-ETHERS Yakshin V.V.a, Tananaev I.G.a, Tsivadze A.Yu.a, Myasoedov B.F.a, Nash K.b a Frumkin Institute of Physical Chemistry and Electrochemistry RAS, Moscow b Washington State University, Chemistry Department, Pullman During the last two decades crown ethers have attracted a great deal of interest for the molecular design of preorganized three-dimensional receptors for different ionic species, including radionu clides. Presently, some information is available about the thermodynamics and control/design of radionuclide recognition by macrocycles, but a detailed mechanistic and structural understanding remains elusive.

Extraction of U, and TRU from nitric acidic media by (4,4(5)) bis(dialkylphosphoryl)-, bis(diphenylphosphoryl)-, bis(O-alkyl)phosphoryl)-dibenzo-n-crown-m ethers (n = 18 and m = 6;

n = 21 and m = 7;

n = 24 and m = 8, respectively) solutions in 1,2-dichloroethane and chloroform has been studied. These reagents were synthesized by Professor Vitaly Kalchenko from the Institute of Organic Chemistry, National Academy of Sciences of Ukraine. It has been demonstrated that, during extraction, distribution coefficients (DM) of Pu(IV), U(VI), Am(III), Eu(III) depend upon experimental conditions as well as upon structural features of the molecular complexes used. It is important that, within the range of [HNO3] = 0,02-1,0M, the DM values for metals depend on stereochemical orientation of phosphoryl-groups. It was found out that the extraction ability of cis(4,4-) isomers is higher than for trans(4,5-) isomers and for their mixtures. Using compound that has cis-oriented (nBuO)2P(O)-groups as an example, it was observed that the highest DU = 0, in 3M HNO3;

DPu = 5,1 in 0,5-3M HNO3, and DAm = 0,007 at pH = 2. For trans-conformer under the same conditions DM for U(VI), Pu(IV), and Am(III) are 0.091, 1.8;

0.003, respectively. Under the same other conditions, the influence of the dimensions of the macrocycle (Cn) upon extraction is essential. Using extraction of Am(III) from 0.01-3M HNO3 as an example, it has been demonstrated that for all molecules investigated, the most effective extragents are crown-ethers with Cn = 21. The shift of the DAmmax to the higher [HNO3] was observed with the increase of n. The sequence of the coordination properties of phosphoryl-containing ligands based upon functionalized benzo-21 crown-7 under extraction of Am(III) from 0.01-3M HNO3 is as follows: (nBuO)(OH)P(O)- (nBuO)2P(O)- Ph2P(O)-. Extraction properties of di(nBuO)(OH)P(O)-dibenzo-21-crown- (DAm = 814 in 0,1M HNO3) are 102 higher for all compounds studied. The conditions of selective separation of Am(III)/Eu(III) by means of bis(O-alkyl)(OH)phosphoryl)-dibenzo-21-crown-7 have been determined with separation factor of 90 at 0.01 M HNO3.

This work supported by U.S. DoE Project RUC2-20010-MO-04.

2460 VIII , , ACTINIDE SOLUTION COMPLEXATION BY ORGANIC LIGANDS OF BIOLOGICAL RELEVANCE Zhang Z.ab, Clark S.B.a, Tian G.b, Rao L.b a Washington State University, Pullman, WA b Lawrence Berkeley National Lab, Berkeley, CA Organic ligands of biological relevance can have a significant impact on the speciation of actinide elements released to the biosphere. Gluconate (shown at the right) is a naturally occurring polyhy droxycarboxylic ligand, that is derived from glucose and that can undergo lactonization and other reactions under various conditions. Many studies have reported on gluconate solution complexation with transition metals,1,2 but complexation of the actinides has received little attention. We have focused on f-element interactions with gluconate and have also considered the impact of lactoniza tion in these systems.

We have studied the gluconate laconization reactions that occur when solution 1 COOH pH drops below ~ 3.5 using potentiometry, NMR, and mass spectrometry. Both - and -lactones were observed at pH values of 1.5 and less;

the -lactone was ob- HCOH served up to pH values as high as approximately 3.0. Their formation is slow, with HOCH -5 - a formation constant for the -lactone at pH 5.0 around 3.2 10 s.

We have determined thermodynamic parameters of gluconate complexation HCOH + 2+ with NpO2 and UO2 over a range of solution conditions using multiple tech- niques including UV-visible-near IR, NMR, x-ray absorption, potentiometric titra- HCOH tions, and calorimetry. For the reaction of the actinyl cation (designated as AnO2x+ H2COH to indicate either neptunyl or uranyl): AnO2x+ + GH4- = AnO2(GH4)(aq), the log for NpO2+ is 1.480.03 compared to 2.20.3 for UO22+. Complexation of uranyl is driven primarily by an entropy gain that is less significant for neptunyl. These re- Gluconic acid (HGH4) sults will be discussed and the coordination modes between the actinyl cations and the gluconate anion will be presented.

References 1. S. Giroux, P. Rubini, B. Henry, S. Aury, Polyhedron, 19, 1567 (2000).


A SUCCESSFUL INTERNATIONAL PROJECT Zhuikov B.L.a, Peterson E.J.b, Srivastava S.C.c a Institute for Nuclear Research of Russian Academy of Sciences (INR), Moscow-Troitsk b Los Alamos National Laboratory (LANL), USA c Brookhaven National Laboratory (BNL), USA For over ten years, a broad collaboration for joint investigations of methods to produce radioiso topes on the basis of powerful Russian and American proton accelerators of medium energy has continued between INR, LANL and BNL. This effort has been supported by the U.S. Department of Energys Initiative for Proliferation Prevention (IPP) program. Many Russian defense institutions are involved in this collaboration as well as commercial companies in the USA and Russia. The main goal is to develop methods and produce isotopes for the diagnosis and therapy of various dis eases.

The most advanced result is the mutual production of 82Sr. INR developed a high-yield target of metallic rubidium which is regularly irradiated at the INR linear accelerator on the diverted MeV proton beam of high intensity (up to 120 A). LANL developed a process of radiochemical recovery of 82Sr from the targets on the basis of a method provided by INR, and installed it in the hot cells in Los Alamos. Many tens of the targets have been processed since 1998 fulfilling an im portant part of 82Sr world demand. BNL as well as institutions from other countries (Canada, South Africa) are also involved in these supplies. 82Sr is used in the USA to prepare 82Rb-generators for effective cardiac perfusion imaging studies. About 100,000 patients have already been treated in the USA using the product supplied by Russia. In addition to this isotope supply, IPP supported the de velopment of production of 82Sr and generator in Russia. This generator has been successfully tested in Russian hospitals.

Production methods for many other isotopes (68Ge, 103Pd, 72Se, 109Cd) have been mutually devel oped involving a number of Russian institutions: Institute for Physics and Power Engineering, Mayak, Karpov Institute of Physical Chemistry, Institute of Geochemistry and Analytical Chem istry and others. An important recent development of INR, BNL and several Russian institutions is production of no-carrier-added (NCA) 117mSn with a specific activity of up to 1300 Ci/g. This high specific activity and the unique nuclear and chemical properties of 117mSn make this isotope ex tremely promising for bone pain palliation, treatment of metastatic cancer in bone, and for cardio vascular applications such as the imaging and treatment of thin-cap fibroatheroma (vulnerable plaque) in patients. Batches of NCA 117mSn produced and supplied by INR are undergoing pre clinical investigations in the USA.

Using the developments of INR, BNL and other institutes, Los Alamos designed and constructed a new powerful isotope production facility on the diverted 100 MeV beam of linear accelerator which has resulted in a great increase of 82Sr production and other isotopes.

The following investigations in the framework of future collaborations are being planned: 1) High level production of 117mSn at LANLs BNLs facilities;

2) Production from Th-targets irradi ated by 160 MeV protons of 225Ac in Ci amounts as well as other -emitters used in cancer therapy;

3) Production of NCA 76As, 67Cu and 64Cu for cancer therapy and for PET diagnostics;

and 4) De velopment of highly productive facility with liquid cycling Rb target and on-line 82Sr extraction with the new method of direct adsorption from liquid metal.

These projects provide an exciting example of a fruitful collaboration between the USA and Russia for promoting research and improvements in the field of medical imaging and therapy, with positive benefits on patient healthcare and peoples well-being on a global scale.


Krasnoyarsk, 660036 Russia Ecological biomonitoring is based on the use of the living organisms. All biological assay systems (bioassays) are nonspecific and integral. These principal properties account for the field of applica tion of bioassays. The use of microorganisms, of marine luminous bacteria in particular, is currently favored. Bioluminescent bioassays are characterized by simplicity, high rate of analysis (1-3 min), and by relatively low prices. Besides, there exists a possibility of varying the complexity of a bio luminescent assay system beginning from intact bacterial cells to enzymatic reactions (in vivo and in vitro, respectively). This provides the comparison of toxic substance action on cell structures and enzymes.

The aim of the research was the investigation of detoxification of radioactive solutions of low activity by humic substances (HS) by bioluminescent assay systems in vivo and in vitro.

The bioluminescent systems we used included: the intact bacteria Ph. Phosphoreum, lyophilized bacteria and the bioluminescent system of coupled enzymatic reactions. The solutions of 241Am(III) and 238U(VI) of different concentrations served as a source of radioactivity. The toxicity of the solu tions was evaluated by relative bioluminescence intensity.

The bioluminescence intensity of the three assay systems on time of exposure to radioactivity in the presence and in the absence of HS was determined. The activation of bioluminescence was ob served at initial period of exposure (up to 20 h), but as the exposure time increased the inhibition took place. Introduction of HS into the systems influenced the obtained effects essentially. The ef fect of HS was shown to depend on a radionuclide concentration, as well as on the complexity and integrity of bioluminescent assay system. Electron-microscopy study showed that HS decrease damage of the bacterial cells in the radioactive solutions.

The studies on localization of americium in cell structures of intact bacteria in the absence and in the presence of HS were carried out. The introduction of HS was found to affect the distribution of Am in cells.

The work was supported by Award No. RUX0-002-KR-06 of CRDF and RF Ministry of Education and Science;

Grant of Molecular and Cellular Biology program of the RAS, Grant 10-7 of RF Ministry of Education and Science.

2464 VIII , , PRODUCTION OF SHORT-LIVED TECHNETIUM ISOTOPES Aliev R.A.a, Ermakov A.N.a, Djungurona G.b a Skobeltsyn Institute of Nuclear Physics, Lomonosov Moscow State University, Leninskie Gory Moscow 119991 Russia b Department of Chemistry, Lomonosov Moscow State University, Leninskie Gory Moscow 119991 Russia There are several reasons of increasing attention to technetium. Technetium produced with high yield in uranium fission, has a considerable mobility in environment and, therefore, is one of the most dangerous radionuclides. Long-lived isotope 99Tc is widely used as a tracer in oceanographic studies, short-lived 99mTc is the main tool of nuclear medicine. Besides, 94mTc may be applied for PET due to high yield of positrons in decay.

Short-lived technetium isotopes 95Tc (T1/2=20 h), 95mTc (T1/2=61 d), 96Tc (T1/2=4.28 d) may be used as tracers in technetium analysis of environmental samples and for studies of technetium chemistry. They are much more convenient in comparison to widely used isotopes 99Tc and 99mTc because the former has no gamma-lines and the latter has very short half-life The aim of this work was the choice of optimal ways of production of 95m,gTc and 96Tc by irra diation of molybdenum and niobium targets by alpha particles with energy up to 30 MeV.

Irradiation were performed on U-120 cyclotron of SINP MSU. Targets of natural isotopic com position were used. The thick target yields of radionuclides were studied as a function of incident particles energy. The depth profiles of radionuclides in the target were determined.

When irradiating of molybdenum part of 95m,gTc produced directly from molybdenum, another way of production is ingrowth from 95Ru (T1/2=1.64 h) decay. Other products of irradiation 97Ru (T1/2=2.9 d) and 103Ru (T1/2=39 d) may be used in 99Tc determination by mass spectrometry, be cause 99Ru is the only stable isobar of 99Tc, and therefore it is necessary to control Ru and Tc sepa ration.

Solvent extraction by methylisobuthylketone, cyclohexanone and trioctylamine was used for separation of technetium from molybdenum and ruthenium. The proposed method allows to obtain isotopically pure 95m,gTc via decay of 95Ru separated from molybdenum target.

The photonuclear reactions also proposed for 95Tc production. Irradiations of ruthenium targets were made by the photons with energy up to 70 MeV in race-track microtron in SINP MSU. In this way 95Tc produced via 95Ru.

VIII , , 2007 INVESTIGATION OF SEDIMENTATION IN KARA SEA FJORDS BY THE MEANS OF RADINUCLIDE TRACERS Aliev R.A.a, Sorokina M.N.b a Skobeltsyn Institute of Nuclear Physics, Lomonosov Moscow State University, Leninskie Gory Moscow 119991 Russia b Department of Chemistry, Lomonosov Moscow State University, Leninskie Gory Moscow 119991 Russia Natural and artificial radionuclides are the powerful tools for investigation of different geophysical processes including sedimentation in lakes, seas and oceans. The aim of this work was estimation of sedimentation rates using radioactive tracers in shallow fjords of Eastern coast of Novaya Zemlya archipelago. The main attention was paid to the fjords where most part of radioactive debris was dumped including objects with spent nuclear fuel.

Sapling was performed by Niemisto gravity corer and boxcorer. Sediment cores were sliced on board to 1-2 cm layers. Radionuclidic composition was determined by gamma ray spectrometry ap plying spectrometer equipped with high pure germanium detector.

Eight cored were sampled in Abrosimov fjord, vertical profiles of 137Cs were determined;

in two cores 210Pb age-dating was done. Distribution of 137Cs has a distinct maximum commonly in 8- cm layer. Differences in location of the maximum may be due to long period of radioactive waste dumping (1964-1991 y.). Values of sedimentation rates determined by 210Pb are 2.8 and 3.0 mm/y, in good consistence with vertical distribution of 137Cs.

The vertical profiles of 137Cs were obtained for six cores in Stepovoj fjord, sedimentation rate was calculated for one point from outer part of fjord, value is 1.2 mm/y. The vertical profiles of Cs significantly differ from cores collected in Abrosimov fjord. 137Cs penetrates in sediments only to 10 cm, maximal activity located in 2-4 cm layer. Therefore it is good correlation between Cs and 210Pb distributions. There is no evidence of bioturbation of sediments.

Also three cores from Tsivolka fjord are analyzed for 137Cs activity.


Institute of Chemistry Far East Branch of Russian Academy of Sciences, 159, ave 100-letiya Vladivostoka, Vladivostok 690022, Russia One of the important applications of hydrothermal technologies is treatment of radioactive wastes.

Treatment of evaporator concentrates of nuclear power plants (NPP) using hydrothermal technolo gies at the oxidation stage for destruction of stable complexes formed by long-lived radionuclides and organic compounds, which limit applicability of sorption technologies, comprise one of such application options1.

Here we discuss the efficiency of hydrothermal oxidation for destruction of organic complexes formed by transition metals, first of all 60Co and 54Mn. We show that hydrothermal oxidation allows significant decrease of time (from 10- to 100-fold as compared to other oxidation methods) required for oxidation of the 60Co-EDTA complex, which stability is the main factor limiting applicability of selective sorption technologies in treatment of evaporator concentrates (Fig.1).

Precipitate volume,% Oxidation by underwater arc Hydrothermal 2 Electrochemical oxidation oxidation 200=250 Oxidation by ozone at 20 Oxidation by ozone at 60 Time 1 min 1h 1 day Fig. 1. Time required for oxidation of 60Co-EDTA complex and volumes of precipitates formed during treatment of evaporator concentrates of atomic power plants by various methods We report the results of laboratory studies of hydrothermal oxidation of several model systems as well as of real evaporator concentrates of nuclear power plants. Results of the development test ing of hydrothermal technology for processing of evaporator concentrates of Novovoronezhskaya NPP during May-November, 2006 are also presented. We show that application of hydrothermal technologies is very promising for treatment of different types of radioactive wastes formed at NPP.

Financial support from the Russian Foundation for Basic Research (grant 05-03-08027) and the company Sci ence-Technology-Production Ltd. is gratefully acknowledged.

References 1. Avramenko V.A., Dobrzhansky V.G., Sergienko V.I., Shmatko S.I., RF patent VIII , , 2007 STUDYING OF STRUCTURAL ORGANIZATION OF SURFACE LAYERS OF SOLIDS BY ATOMIC TRITIUM Badun G.A., Chernysheva M.G., Tyasto Z.A., Mikhalina E.V.

M.V. Lomonosov Moscow State University, Dep. of Chemistry, Div. of Radiochemistry.

119992 Leninskie Gory, Moscow, Russia The phenomenon of selective interaction of tritium atoms which are formed by dissociation of trit ium molecules on tungsten filament at 1500-2200 K with components of solid targets (tritium ther mal activation method) can be used for studying of chemical composition and structural organiza tion of the object. There were obvious successful investigations of biological systems including bacterial ribosome and viruses14 using atomic tritium. It was shown that this method can be applied to studying of surfactant adsorption56. Parameters of tritium atoms interaction such as the ratio of rates of protium substitution with tritium in different components of target and ability of tritium at oms penetrate into the target without energy loss should be known to interpret the data. It is also very important to have knowledge about the dependence of parameters mentioned above on the ex periment conditions. In this case elective introduction of tritium label in different components of target and with different spatial resolution becomes possible.

In present work, studying of tritium atoms interaction with targets of different molecular struc ture and components distribution was carried out. Multilayer targets with certain uniform and indi gested components distribution were tested including surfactant adsorption layers at liquid/gas and solid/gas interfaces, mixtures of amino acids and etc. We have determined the influence of experi ment conditions on the ability of tritium atoms penetrate into the target and react with target com ponents. The temperature of atomizator, gas pressure and time of atomic tritium bombardment were varied. Correlation between structural organization of surface layers of targets and penetration abil ity of tritium atoms was found. The correlation determined can be used not only for biological sys tems but when artificial nanocomposites are investigated by tritium thermal activation technique.

The work has been fulfilled under the support of RFBR (grants 06-03-33036).

References 1. Agafonov D.E., Kolb V.A., Spirin A.S. Proc. Natl. Acad. Sci. U.S.A. 1997, 94, 12892-12897.

2. Shishkov A. V., Goldanskii V. I., Baratova L. A. et al. Proc. Nat. Acad. Sci. USA. 1999, 96, 7827-7830.

3. Baratova L. A., Efimov A.V., Dobrov E.N. et al. Journal of Virology. 2001, 75, 9696-9702.

4. Dobrov E.N., Badun G.A., Lukashina E.V. et al. Eur. J. Biochem. 2003, 270, 3300-3308.

5. Badun G.A., Lukashina E.V., Batuk O.N. et al. Materials Science and Engineering: C. 2003, 23, 797-802.

6. Lukashina E.V., Badun G.A., Chulichkov A.L. Biomol. Eng. 2007. 24, 125-129.

2468 VIII , , CATION-CATION INTERACTION OF ACTINIDES IN SALT MELTS Barbanel' Yu.A., Dushin R.B., Kolin V.V., Kotlin V.P., Nekhoroshkov S.N.

Khlopin Radium Institute, St. Petersburg, Russia The latest results of studying the earlier detected1 phenomenon of cation-cation interaction of acti nides in melts are presented. In the range 700-2000 nm (with emphasis on the 3H53H4 magnetic dipole transition near 1650 nm), the absorption spectra of the NpO2+ (5f2) ion in uranyl-containing melts of different cationic compositions were studied. Processing of the spectra allowed the de tected phenomenon to be considered for the first time in the framework of the mass action law. It was shown that, at the UO22+ concentrations up to 1 mol/l, the equilibrium of the cation-cation in teraction can be described by the reaction NpO2+ + UO22+ NpO2+UO22+;

the concentration sta bility constant of the complex decreases with increasing effective (weighted average) radius of the outer-sphere cations from 0.11 l/mol in the LiCl-KCl-CsCl eutectic melt to 0.043 l/mol in the RbCl 3CsCl melt. To elucidate the mechanism of the cation-cation interaction at cUO2(2+) 1 mol/l, the ab sorption spectra of the NpO2+ ion were studied (at 650700C) in four series of melts with the UO22+ concentration varied in the opposite directions: in the NaCl-KCl-CsCl eutectic melt (1) or a RbCl-3CsCl mixture (2) with growing additions of the Cs2UO2Cl4 complex salt and, in the Cs2UO2Cl4 melt with growing additions of the NaCl-KCl-CsCl eutectic (3) or a RbCl-3CsCl mix ture (4). Processing of the obtained data in terms of the mass action law showed that the formation decomposition reaction of the cation-cation complex can be described adequately to the experimen tal data throughout the UO22+ concentration range studied (up to 4.4 mol/l in molten Cs2UO2Cl4) using the equation of reaction in the form NpO2Cl43 + UO2Cl42 {Cl4ONpOUO2Cl3}4 + Cl.

This corresponds to replacement of one of the chloride ions in the equatorial plane of uranyl(VI) by neptunyl(V). For the first time since our detection of the cation-cation interaction of actinides in melts we could observe this effect in a medium other than chloride systems, namely, in a nitrate melt: The stability constant Ks of the cation-cation complex formed in the NaNO3CsNO3 eutectic by the reaction NpO2+ + UO22+ NpO2+UO22+ was estimated at ~0.6 l/mol.

This study was financially supported by the Russian Foundation for Basic Research (project no.


References 1. Yu. A. Barbanel', R. B. Dushin, V. V. Kolin, V. P. Kotlin, L. G. Mashirov, S. N. Nekhoroshkov, Radiochemistry 2003, 45, no. 3, 276.


SUE SIA Radon, 2/14 Rostovskij per., 119121 MOSCOW, Russia Comprehensive research of environmental effects of radiologically hazardous objects is aimed at studying the influence of both radiological and non-radiological factors (such as chemical pollution agents, heavy metals, etc.).

A method for taking and analysis of environmental samples in the vicinity of a radiologically hazardous object to determine the content of radioactive nuclides and heavy metals was developed, which has been employed since 1961.

The present paper presents the results of studies of soil, surface water, bottom sediments, and snow samples taken in order to determine:

radiation parameters (total alpha and beta activity levels, specific activity of natural and man produced radioactive nuclides);

content of heavy metals.

Radiometric and spectrometric analysis methods involving radiochemical methods of isotope separation were used to determine radiological parameters of environment samples. High-sensitivity radiometric and spectrometric measurement devices using radiochemical methods of concentration and separation of isotopes were used to measure radiological parameters of environment samples.

Gamma radiation sources were measured using an HP-Ge detector with a relative efficiency of 100%, while beta and alpha radiation sources were measured using a TRI-CARB 2550 TR/AB liq uid scintillation analyser. The obtained results are relevant as background level values for the region under study1.

The content of heavy metals in water and snow samples was determined using the Inductively Coupled Plasma with Mass Spectrometry (ICP-MS) method at a VG PlasmaQuad apparatus (UK).

Samples of soils and bottom sediments were analysed using the X-Ray Fluorescence (XRF) spec trometry method at a PW-2400 sequential wavelength spectrometer (the Netherlands). The obtained results were evaluated in comparison with the existing maximum permissible concentration values.

Possible polluting elements were determined based on the heavy metal content in the samples, and distributed into the classes of chemical hazard. The obtained results are suggested to be taken for background level values for the area under study.

According to the evaluated level of radioactive nuclide and chemical pollution hazard, and tak ing into account the hazard class of heavy metals contained in the samples, the observation area of the radiologically hazardous object was classified as clean.

References 1. I. A. Soboleva, E. N. Belyaeva (editors), Manual on methods of environmental radioactivity monitoring. Moscow, Meditsina, 2470 VIII , , RESEARCH OF THE POSSIBYLITY OF APPLICATION OF POLYGONUM SACHALINENSE F. SCHMIDT IN BIOTECHNOLOGY OF GROUND DEACTIVATION Basharin A.V., Ivanov V.V., Kuznetsov D.G., Minaev A.A., Popov I.B.

A.N. Frumkins Institute of physical chemistry and electrochemistry of the Russian Academy of Science, Moscow, E-mail: smith@ipc.rssi.ru Rehabilitation of objects of the environment is one of the priority directions in system of the protec tive actions spent for liquidation of consequences nuclear, chemical and others man-caused of acci dents. However the application of engineering methods at soil treatment from radioactive pollution is ineffectively. It, first of all, is connected to high expenses of work and with necessity of rehabili tation of soil. Therefore now the increasing attention is given to development of biotechnology of rehabilitation of soil. In the given work the researches of the possibility of application of Poly gonum sachalinense F. Schmidt (Polygonum Sakhalin) for extraction of radionuclides from soil are given. Polygonum Sakhalin represents a long-term grassy plant with high productivity. The culture is propagate itself both seeds, and vegetative way and has powerful root system. Participation of the person in the soil rehabilitation by the given technology is connected only to cleaning of biomass, i.e. minimization of the external irradiation of the attendants is achieved.

It is known, that the major factors determining the efficiency of process of deactivation of soil by the given technology are the specific abilities of culture to extraction of radionuclides and their ana logues from the soil, and also the state of the radioisotope in soil-absorbing complex. Therefore in the given work, the influence of the mineral background of feeding on dynamics of development of culture, phytoextraction characteristics in relation to isotopes of cesium and strontium are given.

The behavior of these isotopes in the soil absorbing complex (SAC) differs that the practically all Sr (80-95% from the total contents) pass in the form, easily accessible to root system of plants whereas 137Cs is in the out-of-the-way form. Field experience has been incorporated in Polesskiy state radiation-ecological reserve.

Work is executed at financial support ISTC (Project #B-247) VIII , , 2007 STUDY OF URANIUM DIOXIDE BEHAVIOUR UNDER HYDROTHERMAL CONDITIONS Batuk O.N.a, Kalmykov St.N.a, Zakharova E.V.b, Teterin Yu.A.c, Kriventsov V.V.d a Chemistry department of Lomonosov Moscow State University, Leninskie Gory, Moscow 119992, Russia, b Frumkin Institute of Physical Chemistry and Electrochemistry RAS, Moscow, Russia, c RSC Kurchatov Institute, Moscow, Russia, d Boreskov Institute of Catalysis SB RAS, Moscow, Russia, Uranium dioxide is the main component of the spent nuclear fuel (SNF) and therefore its behaviour in the environment, including its interaction with groundwater, is an important parameter for the evaluation of performance assessment of nuclear repositories. Among radionuclides present in SNF Np could cause a threat to the environment and human health since its long half life period and high migration ability in soluble forms under oxidizing conditions.

The aim of this work was to study the behaviour of the industry produced sample of uranium di oxide in simulated groundwater under 70C and 150C and to study sorption mechanisms and speciation of Np in this system.

Behaviour of industry produced sample of depleted uranium dioxide was investigated. The sam ple was characterized by scanning and transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, extended X-ray absorption fine structure (EXAFS) and X-ray absorption fine structure (XANES). Hydrothermal treatment of the samples was conducted in simu lated groundwater, which mainly contained Na, K and Ca carbonates. Solid phases were periodi cally sampled and analyzed for evolution of the bulk and surface composition, as well as to study uranium secondary phase formation. The neptunium interactions with samples were studied by the sequential extraction technique.

According to the characterization of samples after hydrothermal treatment the essential differ ence in their behaviour under two temperature conditions was established. The bulk oxidation of uranium dioxide is competing with secondary phase formation.

For both samples the quantitative sorption was observed within the week and Np was not leached neither by deionised water nor by the acidic acid solution. Likely the interaction of Np with uranium dioxide could be described either by the formation of low soluble NpO2 or its inclusion into the U(VI)-containing secondary phases forming on the surface.

We acknowledge ISCT for financial support (project 2694).

2472 VIII , , ROLE OF NON-EXCLUSION EFFECTS IN GEL-PERMEATION FRACTIONATION OF HUMIC SUBSTANCES Belyaeva E.Yu.ab, Perminova I.V.a, Kudryavtsev A.V.a, Kulikova N.A.c, Novikov A.P.b a Department of Chemistry, Lomonosov Moscow State University, 119992 Moscow, Russia b Vernadsky Institute of Geochemistry and Analytical Chemistry, 119991 Moscow, Russia c Department of Soil Science, Lomonosov Moscow State University,119992, Moscow, Russia Humic substances are ubiquitous in the environment. They comprise a large class of natural refrac tory organic compounds. By the chemical nature, they represent randomized polymers of polycar boxy- polyhydroxy- aromatic acids. This provides for polyelectrolytic nature of humic molecules.

Large molecular polydispersity is a fundamental property of humic substances that hinders quantita tive evaluation of their molecular weights. Size-exclusion chromatography (SEC) is a powerful technique for determination of the molecular weight distribution (MWD) of synthetic and natural polymers. It has been widely used for analysis of HS. However, due to mentioned polyelectrolytic properties, SEC of HS in aqueous phase is likely to give rise to artifacts. These arise from non-size exclusion effects, which include ionic exclusion and specific adsorption. Ionic exclusion is a non-size exclusion effect arising from repulsive interactions between the charged analyte and the partially charged gel matrix. Specific adsorption occurs as a results of ion exchange adsorption and of hydrophobic or hydrogen bondings that take place between the analyte and gel-matrix. To com pensate for ionic exclusion, modification of eluent by changing of ionic strength is needed. To compensate for specific absorption modification of eluent by addition of organic solvents is needed.

The goal of this research was to define fractionation conditions providing for compensation of non-size exclusion effects upon SEC-analysis of HS.

To evaluate the role of ionic exclusion and specific adsorption in SEC analysis of HS, SEC fractionation of HS was conducted under increasing ionic strength and decreasing polarity of mo bile phase. The first factor was to compensate for ionic exclusion, whereas the second was to pre vent specific adsorption onto column. The ionic strength varied from 0.01 up to 0.13 M (phosphate salts). Organic solvents, such as methanol, acetonitrile and tetrahydrofurane (THF), were used as organic eluent modifier. Also the influence of pH on size-exclusion fractionation of HS was inves tigated.

The possibility for compensation for non-exclusion effects of SEC-analysis of humic substances was demonstrated using modification of eluent by increasing ionic strength and addition of organic solvents.

This research was supported by ISTC (project KR-964) and Interdisciplinary Program of the Lomonosov Moscow State University (project MNP-04, 2007) VIII , , 2007 URANYL HYDROXYLAMINATES AND OXIMATES.

A NEW CLASS OF URANIUM(VI) COORDINATION COMPOUNDS Beyrakhov A.G., Orlova I.M., Mikhailov Yu.N., Gorbunova Yu.E., Il'in E.G.

Kurnakov Institute of General and Inorganic Chemistry, Russian Academy of Sciences, Leninskii pr. 31, Moscow, 119991 Russia A peculiarity of uranium(VI) coordination chemistry is the stability of complexes with ligands able to form chelate ring of a minimum size. In the contrast to the compounds of most d- and f-block elements, for which five- and six-membered chelate rings are stable (Chugaev's rule of chelate rings), uranyl forms stable complexes with three- and four-membered chelate rings. Classical ex amples of such compounds are well-studied uranyl peroxide and carbonate complexes1. Uranyl compounds with hydroxylamine and oximes had not been known by the beginning of our investiga tion.

Up to now we have synthesized a significant number of uranyl compounds, most of them mixed ones, i.e., containing ligands of different nature (oxalate and carbonate groups, hydroxylamine, oximes and their derivatives, neutral ligand, etc) in the inner coordination sphere. The main coordi nation modes of hydrohylamines and oximes in uranyl complexes and the conditions under these coordination modes are observed have been determined. The structure of a number of complexes with different coordination modes of ligands was established by the X-ray crystallography.

For first time unusual coordination modes of ligands to the central atom with the formation of a three-membered N,O-chelate rings have been established (figure). The influence of the structure of the non-donating part of the ligands on the composition, properties, and the structure of the result ing uranyl hydroxylaminates and oximates was shown.

R R1 R UO O N N O N O N O HO N N O O2 U R UO U O2 UO2 UO R UO2 O N R1 N N OH O O2U O N N R R2 O UO UO Fig. Coordination modes of oximes in uranyl complexes.

References 1. "Complex Compounds of Uranium", ed. by I.I.Chernyaev, M. "Nauka", 1964.


Frumkin Institute of Physical Chemistry and Electrochemistry RAS, Moscow Preparation of uranium, neptunium and plutonium in the prescribed oxidation states and many aqueous processes of spent nuclear fuel and radioactive waste reprocessing in a number of cases are connected to slow passing of the redox reactions. Catalysts on the basis of the platinum group met als may be well used for their acceleration1.

The comparative study of the Pt/SiO2, Pd/SiO2 and Ru/SiO2 catalytic activity in the reactions of uranium(VI) and neptunium(V) catalytic reduction with hydrazine and formic acid was undertaken aimed to find a substitute to expensive and scarce platinum. The originally prepared catalysts were distinguished by the content and the size of active metal nanocrystallites on the support.

It is found that the catalysts were sufficiently different by their ability to initiate redox reactions in the systems under the study. The Pt/SiO2 catalysts were found to be active in the reactions of U(VI) and Np(V) catalytic reduction with hydrazine and HCOOH in the solution of mineral acids of any nature. The ruthenium catalysts initiate only reduction of neptunium(V) in the nitric acid solu tion at [HNO3] 1.5 M but they were not active towards to uranium(VI) reduction in any media.

Comparative analysis of the activity of the catalysts on the basis of Pt and Pd showed that the palla dium catalysts possessed higher catalytic activity than the platinum catalysts in the reactions of U(VI) and Np(V) catalytic reduction with HCOOH in the non-nitrate acidic media but in the nitric acid solutions catalysts Pd/SiO2 did not display the catalytic activity and were not chemically stable.

Mechanisms of the heterogeneous catalytic transformations in the presence of Pt/SiO2, Pd/SiO and Ru/SiO2 are different. They are determined by the chemical nature of active metal. In the case of Pt/SiO2 and Ru/SiO2 catalysts the reactions proceed by the interaction of an actinide ion and re ducing agent molecule adsorbed on the neighbor sites of catalysis. The electron transfer is realized through the Me Me metal bridge. Redox reactions in the presence of Pd/SiO2 start by the interac tion of Pd surface atoms with N2H4 or HCOOH molecules followed by the hydrogen atoms re moval. The chemisorbed hydrogen atoms play the role of active reducing species.

The principles of the chemical and structural selectivity of Pt/SiO2, Pd/SiO2 and Ru/SiO2 cata lysts in the redox reactions of actinide ions in aqueous acidic media have been determined on the basis of comprehensive studies of the reaction mechanisms and the dependences of the specific catalytic activity on the size of the active metal nanocrystallites.

The work was fulfilled with the financial support of RFBR Grant 03-03-32239 and of the RAS DCMS Program 9.

References 1. A.V. Ananiev, I.G. Tananaev, V.P. Shilov. Russian Chemical Reviews, 2005, 47 (11), P. 11321155.


Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Science.

Leninskii pr. 31, 119991, Moscow The interaction of long-living radionuclides 237Np and 239Pu with clay minerals is one of the impor tant mechanisms of decrease of their mobility in geological environments. The sorption capacity of clay minerals depends on many factors such as ionic form of the actinides in solution, structure and properties of the clay, pH value, temperature, presence of inorganic and organic ligands.

The present work was aimed to carry out the systematic studies of the Np(V) and Pu(IV) sorp tion behaviour related to layered clays. It was shown that under aerobic conditions, kaolinite and montmorillonite demonstrated rather high sorption capacity. Thus in noncomplexing media the ob tained distribution ratio is equal to about 400 700 ml/g for Np(V) and Pu(IV), respectively.

We have studied how the adsorption efficiency of Np(V) and Pu(IV) is affected by addition of some chelating agents, in particular, pyridine and imidazole derivatives, the common components of animals and plants or products of their metabolism.

It has been established that N-bearing heterocyclic ligands strongly bind neptunium- and pluto nium-ions due to formation of chelate complexes. Both calculation of the constants of complex formation and X-ray diffraction study of solid compounds structure have shown that the strongest actinides complexes are formed with pyridine-2-carboxylic and pyridine-2,6-dicarboxylic acids, which are capable to form steady five-membered metallorings. At the presence of these ligands the sorption process changes dramatically and in a range of temperatures 20-130C radionuclides re main in solution for a long time.

Pyridine-3- and pyridine-4-carboxylic acids render less significant influence on Np(V) and Pu (IV)sorption by the clays, significantly reducing interphase distribution factors of the radionuclides, however not reducing them to zero. The certain correlation between structure of N-bearing ligands and their influence on the sorption affinity of the kaolinite and montmorillonite toward long-living radionuclides both in static and in dynamic conditions is marked.

Financial support was provided by Russian Academy of Sciences (the Programme of the Basic Chemistry Research 9) 2476 VIII , , PHOSPHATES OF LANTHANIDES, NEPTUNIUM AND PLUTONIUM.

SYNTHESIS, STRUCTURE, PROPERTIES Bykov D.M.a, Konings R.J.M.b, Orlova A.I.a a Nizhny Novgorod State University, Chemical Department, Gagarin Ave., 23, 603950, Nizhny Novgorod, Russia b European Commission, JRC, Institute for Transuranium Elements, P.O. Box 2340 D-76125 Karlsruhe, Germany The present work is the continuation of our complex research of NaZr2(PO4)3-type phosphates (NZP) dedicated to exploration of possibility of their use as matrices for incorporation of HLW components, in particular actinides and their analogues lanthanides.

The phosphates of general type R0.33Zr2(PO4)3 (R = Y, La, lanthanides), M0.25Zr2(PO4)3 (M = Np, Pu), were selected for the present study as well as series of solid solutions TxPu0.25(1-mx)Zr2(PO4)3, T = Na, Ca (m = 1 and 2, respectively). Synthesis of the samples was carried out from water solutions with the use of different variations of the precipitation method, including sol-gel procedure and cit rate method. In an earlier work1 we established that R0.33Zr2(PO4)3 phosphates crystallize in a new space group for NZP-type compounds P 3 c;

their thermodynamic properties in the high temperature range were investigated2. The influence of synthesis method on the upper temperature limit of phase homogeneity was shown for Eu0.33Zr2(PO4)3 phosphate, it increased up to approxi mately 1000 C.

The XRD patterns of phosphates Np0.25Zr2(PO4)3 and Pu0.25Zr2(PO4)3, obtained after calcinations of the precursor powders at 8000C, had a set of reflections relating to NaZr2(PO4)3-structure. Yet, the presence of additional reflections of low intensity, not typical for this structure, by analogy with R0.33Zr2(PO4)3 phosphates was accounted for the reduction of symmetry of crystal structure. The diffraction pattern of the phosphate Pu0.25Zr2(PO4)3, which was obtained after additional heating of the sample at 9000C during 20 hours, revealed distinction in thermal behavior of the studied com pound from isostoichiometric phosphates of 3- and 4-valent elements (Eu, Zr, Hf and others), syn thesized by the same method and conforms to the results of our earlier research3.

The XRD patterns of the samples of TxPu0.25(1-mx)Zr2(PO4)3 series (T = Na (m = 1);

T = Ca (m = 2)), synthesized by sol-gel method with the use of inorganic reactants, were attributed to NZP struc ture type, while dependences of unit cell parameters versus composition indicated formation of con tinuous rows of solid solutions.

Simultaneous inclusion of Na, Ca, Pu in composition of solid solutions of the NZP-type demon strates the possibility of variation of percentage of actinides in composition of compounds, and is a prerequisite for creation of actinide-containing materials with controllable thermomechanical prop erties.

This work was financially supported by Russian Ministry of Education and Science, the DAAD and the European Commission in the frames of programs Michail Lomonosov and In-service training respectively.

References 1. D.M. Bykov, E.R. Gobechiya, Yu.K. Kabalov et al., J. Solid State Chem. 2006, 179, 3101.

2. D.M. Bykov, R.J.M. Konings, A.I. Orlova, J. Alloys Compd. (2007), doi:10.1016/j.jallcom.2006.11.120.

3. D.M. Bykov, A.I. Orlova, S.V. Tomilin et al., Radiochemistry 2006, 48, 211.


Institute of Problems of Chemical Physics, RAS, Chernogolovka, 142432 Russia In the theory and practice of a storage of high-level radioactive wastes (RAWs) now are considered as the most preferable two expedients of an immobilization carried out through a high-temperature stage: a vitrifying of the RAWs or their capture in ceramic matrixes of SYNROC-type. However vitreous matrixes not to the full meet the requirements of radioecological safety, SYNROC-type ceramics is complicated on manufacturing techniques. Thus, the development of a large-scale proc ess for production of the material providing RAWs immobilization with high energy and economi cal efficiency is very urgent.

Phase composition, specific surface area, pore volume, and pore size distribution of the monoliths prepared from synthetic calcium aluminosilicate (SCAS) were studied before and after action of the leaching solution.

The initial synthetic calcium aluminosilicate powder for forming monoliths was prepared by superadiabatic combustion of the charge containing fly ash of thermoelectric power stations and limestone. Cold pressing of the SCAS powder yields low-porosity monoliths with initial compression strength of 80 MPa;

upon subsequent storage in air, this parameter sharply increases and reaches 130-140 MPa after 28-day hardening.

The matrices studied are polycrystalline glass-ceramic samples containing 30-60 wt% glassy phase (the remainder are polycrystals). Solidification of the monolithic samples is due to the reaction of -dicalcium silicate with water, yielding calcium hydrosilicate CaOSiO2H2O, which possesses binding properties, and portlandite [Ca(OH)2]. In turn, portlandite reacts with active silica (SiO2) forming secondary CaOSiO2H2O gel, which fills cavities and decreases the size of the capillary pores.

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