Capability assessment for application of clay mixture as barrier material for irradiated zirconium alloy structure elements long-term processing for storage during decommissioning of uranium-graphite nuclear reactors

The radionuclide composition and the activity level of the irradiated zirconium alloy E110, the radionuclide immobilization strength and the retention properties of the mixed clay barrier material with respect to the radionuclides identified in the alloy were investigated to perform the safety assessment of handling structural units of zirconium alloy used for the technological channels in uranium-graphite reactors. The irradiated zirconium alloy waste contained the following activation products:{93m}Nb and the long-lived {94}Nb, {93}Zr radionuclides. Radionuclides of {60}Co, {137}Cs, {90}Sr, and actinides were also present in the alloy. In the course of the runs no leaching of niobium and zirconium isotopes from the E110 alloy was detected. Leach rates were observed merely for {60}Co and {137}Cs present in the deposits formed on the internal surface of technological channels. The radionuclides present were effectively adsorbed by the barrier material. To ensure the localization of radionuclides in case of the radionuclide migration from the irradiated zirconium alloy into the barrier material, the sorption properties were determined of the barrier material used for creating the long-term storage point for the graphite stack from uranium-graphite reactors

Multi-Agent Analysis of Scenarios for "arctic Smart City"

An approach to formalizing problems of municipal management in the Russian Arctic via smart city technologies is considered on the example of city Salekhard. An analysis of modern smart city concepts and prospects for integrating such technologies as BIM, GIS, and CIM is given. A discussion is based on comparison of two options to implement smart city technologies. Those are: 1) the inertial scenario of development adopted in the Strategy of the municipality Salekhard city, and 2) an alternative scenario corresponding to the innovation model of multicomponent sustainable system which includes energy subsystems. A multi-agent formalization of city management presents specific object features, including factors of the Northern nature. The framework of a four-component model of the flow distribution of resources: material, energy, information, financial, is applied. © Published under licence by IOP Publishing Ltd.The reported research was partly funded by Russian Foundation for Basic Research and the government of the Yamal region of the Russian Federation, grant № 19-48-890001

Methods of the determination of inorganic arsenic species by stripping voltammetry in weakly alkaline media

Two methods are considered for the direct determination of trace amounts of As(III) and As(V) in solutions by stripping voltammetry (SVA) using an ensemble of gold microelectrodes (Au-MEA) previously developed by the authors of this paper. In both methods, analyzing a mixture of As(III) and As(V), analysts first record an SVA signal of As(III) in a supporting Na2SO3 electrolyte. To record an analytical SVA signal of As(V), in the first method one should use the reduction of As(V) to As(III) on the surface of an Au-MEA catalyzed by the system Mn(II)/Mn(0) and followed by the formation of As(0) and its anode dissolution. In the second method, the photoreduction of As(V) to As(III) in a Na2SO3 solution is conducted under UV irradiation followed by the reduction of As(III) to As(0) and its electrooxidation on Au-MEA. The two methods are compared taking into account their performance characteristics and interfering ions. To improve the reliability of the results of analysis at an insignificant increase in its cost, we propose the consecutive use of both methods. The procedures are simple and rapid, do not require the removal of dissolved oxygen or toxic reactants, and can be used for the analysis of aqueous solutions at the place of sampling. The results of analyses of real objects, snow, river water, and process solutions are presented

Unconventional magnetism of non-uniform distribution of Co in TiO2 nanoparticles

High-resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD) analysis, electron paramagnetic resonance (EPR), X-ray absorption spectroscopy (XAS), magnetic methods, and density-functional theory (DFT) calculations were applied for the investigations of Co-doped anatase TiO2 nanoparticles (∼20 nm). It was found that high-spin Co2+ ions prefer to occupy the interstitial positions in the TiO2 lattice which are the most energetically favourable in compare to the substitutional those. A quantum mechanical model which operates mainly on two types of Co2+ – Co2+ dimers with different negative exchange interactions and the non-interacting paramagnetic Co2+ ions provides a satisfactorily description of magnetic properties for the TiO2:Co system. © 2020 Elsevier B.V.Russian Foundation for Basic Research. Ministry of Science and Higher Education of the Russian Federatio

The Fermi surface and the role of electronic correlations in Sm2−x_{2-x}Cex_{x}CuO4_4

Using LDA+GTB (local density approximation+generalized tight-binding) hybrid scheme we investigate the band structure of the electron-doped high-$T_c$ material Sm$_{2-x}$Ce$_{x}$CuO$_4$. Parameters of the minimal tight-binding model for this system (the so-called 3-band Emery model) were obtained within the NMTO ($N$-th order Muffin-Tin orbital) method. Doping evolution of the dispersion and Fermi surface in the presence of electronic correlations was investigated in two regimes of magnetic order: short-range (spin-liquid) and long-range (antiferromagnetic metal). Each regime is characterized by the specific topologies of the Fermi surfaces and we discuss their relation to recent experimental data.Comment: 10 pages, 4 figures, 1 table, Published versio

Capability assessment for application of clay mixture as barrier material for irradiated zirconium alloy structure elements long-term processing for storage during decommissioning of uranium-graphite nuclear reactors

The radionuclide composition and the activity level of the irradiated zirconium alloy E110, the radionuclide immobilization strength and the retention properties of the mixed clay barrier material with respect to the radionuclides identified in the alloy were investigated to perform the safety assessment of handling structural units of zirconium alloy used for the technological channels in uranium-graphite reactors. The irradiated zirconium alloy waste contained the following activation products:{93m}Nb and the long-lived {94}Nb, {93}Zr radionuclides. Radionuclides of {60}Co, {137}Cs, {90}Sr, and actinides were also present in the alloy. In the course of the runs no leaching of niobium and zirconium isotopes from the E110 alloy was detected. Leach rates were observed merely for {60}Co and {137}Cs present in the deposits formed on the internal surface of technological channels. The radionuclides present were effectively adsorbed by the barrier material. To ensure the localization of radionuclides in case of the radionuclide migration from the irradiated zirconium alloy into the barrier material, the sorption properties were determined of the barrier material used for creating the long-term storage point for the graphite stack from uranium-graphite reactors

HYDROTHERMAL SYNTHESIS, MORPHOLOGY AND PROPERTIES OF NANOCOMPOSITES BASED ON VANADIUM OXIDE V2O3@C

В данной работе предложен новый гидротермальный метод получения нанокомпозита V2O3@C. Методом РФА проведена идентификация полученного образца. С помощью КР-спектроскопии и термогравиметрического анализа доказано наличие углерода в полученном композите V2O3@C. Морфология и размеры частиц изучены с помощью СЭМ. Площадь удельной поверхности и преимущественный диаметр пор рассчитаны методом БЭТ.In this work, a new hydrothermal method for obtaining nanocomposite V2O3@C was proposed. The XRD method was used to identify the sample obtained. With the help of Raman spectroscopy and thermogravimetric analysis, the presence of carbon in the resulting composite V2O3@C has been proved. Morphology and particle sizes were studied by SEM. The specific surface area and the preferred pore diameter were calculated by the BET method.Работа выполнена при финансовой поддержке РФФИ-ГФЕН Китая (проект № 16-53-53069)