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Stefanovsky S.V.,Moscow Scientific and Industrial Association | Purans J.J.,Institute of Solid State Physics
Physics and Chemistry of Glasses: European Journal of Glass Science and Technology Part B | Year: 2012

Cesiums ion speciation in sodium cesium borosilicate and sodium aluminophosphate glasses potentially suitable for immobilization of Cs-containing radioactive wastes or ionizing radiation sources was studied using x-ray absorption spectroscopy (XAS). At relatively low Cs2O content (~1-2 mol%) in Na-Cs borosilicate glasses, Cs ions are present in a slightly distorted twelve-fold coordinated oxygen environment where nine oxygens are positioned at a distance of 3·22 Å and three - at a distance of 3·37 Å. The closest Si atoms are positioned at a distance of ~3·31 Å. With the increase of Cs2O concentration in the glass both the coordination number (CN) and the average Cs-O distances reduce, whereas, the Cs-Si distances increase. Both the first and the second coordination shells are split into two subshells pointing to distortion of cesium-oxygen polyhedra. Source

Veselov E.I.,Moscow Scientific and Industrial Association
Atomic Energy | Year: 2011

This article is devoted to the development of a systems approach to evaluating the safety of radwaste repositories. A structural diagram of the geoenvironmental system radiologically-dangerous-object- environment is presented. The scheme of interconnections, acting forces, and changes occurring in the system is examined. Complex safety criteria are determined. The structure proposed for the geoenvironmental factors controlling the safety of a radiologically dangerous object makes it possible to develop appropriate methods of regulating the physical, hydrogeological, and geochemical properties of the protective barriers and the degree to which the environment affects the object. The systems approach developed can be used to evaluate the environmental safety of different objects and make decisions as to the need for restoring the environmental safety of facilities. © 2011 Springer Science+Business Media, Inc. Source

Savkin A.E.,Moscow Scientific and Industrial Association
Radiochemistry | Year: 2011

Laboratory trials of a process for sorption decontamination of real NPP bottom residues from Cs radionuclides with Termoksid-35 ferrocyanide sorbent and rig and pilot trials of the technology for reprocessing of bottom residues from a number of Russian nuclear power plants were performed. The efficiency of the Cs sorption drastically decreases in the presence of organic complexing agents (EDTA, oxalate ions). Preliminary ozonation of the bottom residue allows the working life of Termoksid-35 sorbent in the decontamination process to be increased by a factor of several tens. Rig and pilot trials showed that ozonation of bottom residues, followed by microfiltration separation of the precipitate formed, ensures efficient decontamination of the solutions from Co, Mn, and Sr radionuclides and from α-emitters. A technology was suggested for decontamination of NPP bottom residues from radionuclides, involving ozonation, microfiltration, and selective sorption of Cs radionuclides on Termoksid-35 ferrocyanide sorbent. Process and technical solutions obtained in the course of trials were implemented in an industrial installation for reprocessing of bottom residues from the Kola NPP. © 2011 Pleiades Publishing, Ltd. Source

Krivovichev S.V.,Saint Petersburg State University | Yudintsev S.V.,RAS Institute of Geology and Mineralogy | Stefanovsky S.V.,Moscow Scientific and Industrial Association | Organova N.I.,RAS Institute of Geology and Mineralogy | And 2 more authors.
Angewandte Chemie - International Edition | Year: 2010

A polysomatic series of complex oxides for actinide immobilization is based on the incorporation of pyrochlore nanoclusters (light brown) into modified murataite-like frameworks (blue). Oxides from this series may be viewed as a complex form of radioactive waste and are one of the most elaborate families of nanoscale-tuned complex oxides known to date. Copyright © 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. Source

Kozlovsky I.V.,Moscow Scientific and Industrial Association
Atomic Energy | Year: 2012

A γ-spectroscopic method of monitoring the activity of solid radwastes with different composition was studied. The method developed is intended for direct measurement of the activity of radionuclides with γ-ray energy 50 1000 keV in solid radwastes with density 100-2500 kg/m 3. A series of control measurements was performed to determine the reliability of the calculation of the activity of γ-emitting nuclides in containers by means of the gamma-spectrometric complex and to establish the uncertainties. The additive was placed at the top and center on the axis of rotation of the container. Next, the activity of the containers with the additives was determined. The desired values were obtained by subtracting the activity of the additive material from the total activity. For each container with different materials, 21 measurements without additives were performed to estimate the average activity and statistical error. This method of analysis can be used to monitor the activity of radioactive wastes and other radiation hazardous objects. Source

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