Possibility of separating spent nuclear fuel components by a plasma method in azimuthal magnetic and radial electric fields

We consider the method of plasma separation of spent nuclear fuel in a system with an azimuthal magnetic field and the electric potential produced by electrodes located in a magnetized plasma. The results of calculation of trajectories of ions simulating uranium and the first peak of its fission products in the oneparticle approximation are described. The effect of the initial position and the initial velocity of ions on their trajectories is analyzed. The conditions ensuring the spatial separation of ions in the groups of masses admissible for practical realization are specified; it is shown that currents on the order of 100 kA through the central conductor and electrostatic potentials on the order of 1 kV are required for this purpose.     

Study of the feasibility of distributed cathodic arc as a plasma source for development of the technology for plasma separation of SNF and radioactive wastes

One of the key problems in the development of plasma separation technology is designing a plasma source which uses condensed spent nuclear fuel (SNF) or nuclear wastes as a raw material. This paper covers the experimental study of the evaporation and ionization of model materials (gadolinium, niobium oxide, and titanium oxide). For these purposes, a vacuum arc with a heated cathode on the studied material was initiated and its parameters in different regimes were studied. During the experiment, the cathode temperature, arc current, arc voltage, and plasma radiation spectra were measured, and also probe measurements were carried out. It was found that the increase in the cathode heating power leads to the decrease in the arc voltage (to 3 V). This fact makes it possible to reduce the electron energy and achieve singly ionized plasma with a high degree of ionization to fulfill one of the requirements for plasma separation of SNF. This finding is supported by the analysis of the plasma radiation spectrum and the results of the probe diagnostics.     

T-irreducible extension of polygonal digraphs

Directed graphs are mathematical models of discrete systems. T-irreducible extensions are widely used in cryptography and diagnosis of discrete systems. A polygonal origraph is a digraph obtained from a circuit by some orientation of its edges. We propose an algorithm to construct a T-irreducible extension of a polygonal graph.     

Total cross sections for fission of heavy nuclei by intermediate-energy protons

The results of measuring total cross sections for proton-induced fission of ^natPb, ²⁰⁹Bi, ²³²Th, ²³³U, ²³⁵U, ²³⁸U, ²³⁷Np, and ²³⁹Pu nuclei at proton energies from 200 to 1000 MeV are reported. The measurements were carried out in steps of ≈100 MeV. Complementary fission fragments were detected in coincidence by two parallel-plate avalanche gas counters placed in the beam line on both sides of the thin target close to it. Energy and isotope dependences of the fission cross sections are analyzed.     

Electronic properties of the polycrystalline tin dioxide interface with conjugated organic layers

The results on the electronic structure of the unoccupied electronic states of the polycrystalline SnO₂ in the energy range from 5 eV to 25 eV above the Fermi level are presented. The modification of the electronic structure and of the surface potential upon deposition of the ultrathin films of copper phthalocyanine (CuPc) and of perylene tetracarboxylic acid dianhydride (PTCDA) film onto the SnO₂ surface were studied using the very low energy electron diffraction (VLEED) method and the total current spectroscopy (TCS) measurement scheme. A substantial attenuation of the TCS signal coming from the SnO₂ surface was observed upon formation of a 1.5–2 nm thick organic deposit layer while no new spectral features from the deposit were distinguishable. It was observed that the electronic structure typical for the organic films was formed within the organic deposit thickness range from 2 nm to 7 nm. The interfacial charge transfer was characterized by the formation of the polarization layer up to 5 nm thick in the organic films. The PTCDA deposition on SnO₂ was accompanied by the negative charge transfer onto the organic layer and to the 0.65 eV increase the surface work function. At the CuPc/SnO₂ interface, the negative charge was transferred to the SnO₂ surface and the overall surface work function decreased by 0.15 eV.     

Analysis of the diamagnetic effect in multipole Galatea traps

The toroidal current emerging after the injection of a plasmoid through the magnetic shell of the Trimyx-3M (microwave) multipole trap is measured using the Rogowski loop. This current is due to diamagnetism of the plasma. The relation between the diamagnetic current and the maximal plasma pressure produced at the magnetic field separatrix is obtained. It is shown hence that magnetic measurements in a multi-pole trap for a known concentration make it possible to determine the plasma temperature in the trap and the energy confinement time.     

Peculiarities of the Interaction of Rare-Earth Metal Thiocyanates with s-Triazine

Russian Journal of Coordination Chemistry - The reactions of thiocyanates Ln(NCS)3 ? 6H2O (Ln = Y, Eu, and Tb) with 2,4,6-tris(2-pyridyl)-s-triazine (Tptz) in МеОН,...     

Specific features of the structure,reactivity, thermolysis,and magnetism of cymantrenecarboxylate complexes of lanthanides

The properties of the cymantrenecarboxylate (containing (CO)₃ Mn(η⁵-C₅H₄CO₂ ^- group) complexes of lanthanides obtained and studied by the authors in the years 2009–2015 are reviewed. The complexes represent a new type of heterometallic 3d–4f compounds. Both binuclear and polymer complexes of various types are synthesized. The variation of the synthesis conditions and the use of additional ligands make it possible to successively change the Mn: Ln ratio in a molecule of the compounds and to obtain the ratio equal to 3: 1, 2: 1, and 1: 1. The polymeric heteroleptic derivatives, acetate and acetyacetonate cymantrenecarboxylates, are synthesized. Using the photolabile cymantrene fragment as a source of Mn²⁺ ions, polynuclear Mn–Ln heterometallic cymantrenecarboxylates are obtained under the oxidative photolysis conditions. The influence of binuclear neodymium cymantrenecarboxylate on the polymerization of dienes is studied. The structures of the complexes, their physicochemical properties, and possibilities of practical application are considered.