[en] Short note

[en] Highlights: • Fast sodium reactors provide the background for two-component nuclear energy system. • The engineering solutions for BN-1200M aim at enhancing safety and performance. • The results of the R&D ensure the competitive level required for BN-1200 power units.

[en] Two polymorphic modifications of 1-acetyl-3-(4-nitrophenyl)-5-(2'-furyl)pyrazoline (I) are investigated by X-ray diffraction with the purpose of analyzing the factors responsible for the formation of crystal structures of the optical nonlinear organic compounds. Both modifications crystallize simultaneously upon slow evaporation of a solution of compound I in an isopropanol-acetonitrile (3 : 1) mixture. It is found that the molecular geometry of the polymorphic modifications is characterized by the rotation of the furan substituent with respect to the plane of the pyrazoline ring. The molecular hyperpolarizabilities (β) of both conformers are calculated

[en] Authors demonstrate results of experimental scale-model studies on functional characteristics of a check valve used in the safety system of a liquid-metal-cooled reactor. Check valve model fluid dynamic characteristics obtained in the course of experimental studies are shown in diagrams as functions of some design and operation parameters of the model

[en] The derivatives of 3-(4-nitrophenyl)-2-phenylacrylic acid are synthesized. It is shown that the chemical modification of this acid results in a change in the symmetry of the supramolecular fragment formed by molecules in the crystal. In turn, this change leads to a change in the crystal symmetry and favors the formation of a noncentrosymmetric crystal structure. The crystal structures of 3-(4-nitrophenyl)-2-phenylacrylic acid (I), 3-(4-nitrophenyl)-2-phenyl-triethyl aminoacrylate (II), and 3-(4-nitrophenyl)-2-phenylacrylic acid (3-methoxy)phenyl ester (III) are investigated by X-ray diffraction

[en] The products of crystallization of 4-hydroxybenzaldehyde-4-nitrophenylhydrazone (I) and N'-(2-phenyl-1H-indole-3-aldehyde)-4-nitrophenylhydrazone (II) from different solvents are studied by X-ray diffraction with the aim of examining the polymorphism of hydrazone derivatives. The structural features of the crystals prepared are analyzed. It is shown that, in the case when molecules of organic compounds with a high molecular hyperpolarizability are capable of forming stable acentric supramolecular associates in the crystal, knowledge of their polymorphism offers strong possibilities for designing the noncentrosymmetric crystal structure necessary for a manifestation of the nonlinear optical activity

[en] To purify primary sodium in the advanced BN-1200 reactor plant, a purification system with cold traps has been used that are located in the reactor vessel (in-built purification system). Such decision has excluded external communications of the auxiliary system with radioactive sodium and respectively a possibility that sodium will outflow to compartments outside the reactor. The sizes of cold traps located in the reactor are small that has limited the sodium flowrate through them, impurity storage capacity, and has made it necessary to replace traps in the course of reactor plant operation. Cold traps include such main components of the conventional external purification system as sodium communications, a portion of the cooling circuit, flow meter devices, and electromagnetic devices (a pump and throttle pump) to ensure sodium circulation and to control the sodium flowrate. In the course of development, options have been considered to cool traps with argon, liquid sodium, and gallium. To validate operation of electromagnetic devices for the cold trap, a package of research activities and R&D activities has been done: - thermal irradiation studies have been done of sample electrotechnical materials intended for the electromagnetic pump and throttle pump. - mockups of the electromagnetic pump and throttle pump have been manufactured and tested. (author)

[en] To purify primary sodium in the advanced BN-1200 reactor plant, a purification system with cold traps has been used that are located in the reactor vessel (in-built purification system). Such decision has excluded external communications of the auxiliary system with radioactive sodium and respectively a possibility that sodium will outflow to compartments outside the reactor. The sizes of cold traps located in the reactor are small that has limited the sodium flowrate through them, impurity storage capacity, and has made it necessary to replace traps in the course of reactor plant operation. Cold traps include such main components of the conventional external purification system as sodium communications, a portion of the cooling circuit, flow meter devices, and electromagnetic devices (a pump and throttle pump) to ensure sodium circulation and to control the sodium flowrate. In the course of development, options have been considered to cool traps with argon, liquid sodium, and gallium. To validate operation of electromagnetic devices for the cold trap, a package of research activities and R&D activities has been done: - thermal irradiation studies have been done of sample electrotechnical materials intended for the electromagnetic pump and throttle pump. - mockups of the electromagnetic pump and throttle pump have been manufactured and tested. (author)

[en] We report results of experiments performed with the KEDR detector at the VEPP-4M e⁺ e^- collider.They include precise measurement of the D⁰ and D^± meson masses, determination of the ψ(3770) resonance parameters,and a search for narrow resonances in e⁺ e^- annihilation at center-of-mass energies between 1.85 and 3.1 GeV. (authors)

[en] We present a study of the inclusive photon spectra from 5.9 million J/ψ decays collected with the KEDR detector at the VEPP-4M e⁺ e^- collider. We measure the branching fraction of radiative decay J/ψ → η_c γ, η_c width and mass. Our preliminary results are: M(η_c)=2979.4 ± 1.5 ± 1.9 MeV/c², Γ(η_c)=27.8±5.1±3.3 MeV, Β(J/ψ → η_c γ)=(2.34 ± 0.15 ± 0.40)%. (authors)