Персона: Степанов, Владимир Александрович
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ИАТЭ НИЯУ МИФИ
ИАТЭ НИЯУ МИФИ был образован в 1953 г. как вечернее отделение МИФИ. В 2009 г. ИАТЭ официально получил статус обособленного структурного подразделения НИЯУ «МИФИ», что дало новый мощный импульс для развития образовательной и научной деятельности на основе инновационной составляющей. В соответствии с лицензией Минобрнауки России ИАТЭ ведет образовательную деятельность в рамках очной, очно-заочной и заочной форм обучения. В настоящее время в ИАТЭ НИЯУ МИФИ осуществляется подготовка по очной форме обучения: бакалавриат- 16 направлений, специалитет – 4 направления, магистратура- 12 направлений; по очно-заочной: бакалавриат- 4 направления, специалитет – 1 направление; по заочной: бакалавриат- 3 направления, специалитет- 2 направления; аспирантура – 18 направлений.
В структуре ИАТЭ 9 факультетов: физико-энергетический, естественных наук, кибернетики, социально-экономический, медицинский, вечерний, заочного обучения, подготовительный, повышения квалификации и профессиональной переподготовки специалистов. Образовательный процесс обеспечивают 18 общеобразовательных и 22 выпускающие кафедры.
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Владимир Александрович
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- ПубликацияТолько метаданныеRadiation hardening and optical properties of materials based on SiO2(2021) Stepanov, V. A.; Demenkov P. V.; Nikulina, O. V.; Степанов, Владимир Александрович© 2021 Obninsk Institute for Nuclear Power Engineering, National Research Nuclear University 'MEPhI'. All rights reserved.In preliminary studies, it was shown that the optical absorption spectra of radiation colored glasses are the spectra of optical losses due to scattering by optical inhomogeneities. Optical inhomogeneities in glasses of various compositions arise due to the radiation separation of the electric charge and polarization in nanosized structural elements. The authors of this work prove that the radiation changes in the mechanical and optical properties of silica glasses are of the same nature. The performed estimates indicate that the separation of the electric charge in glasses occurs up to absorbed doses of about 1 MGy. The local separation of the electric charge due to the appearance of Coulomb forces leads to the radiation Coulomb hardening of glasses. The estimate of the Coulomb hardening of quartz glasses was ~ 1•107 Pa. The theoretical results were experimentally confirmed by measuring the mechanical properties of glasses under high intensity proton irradiation as well as by testing the mechanical strength of a composite material based on quartz glass. Under proton irradiation with a dose rate of 5•103 Gy/s (energy of 8 MeV) up to threshold doses of ~ (1-5)•106 Gy in KU 1 quartz glasses, the decrement of acoustic vibrations decreased due to the Coulomb hardening. After gamma irradiation with 1.34•105 Gy, the tensile strength of a composite material based on quartz glass increased by up to 20 MPa. This value is in the range of estimates of the Coulomb hardening of quartz glasses. It is also shown that ionizing radiation does not affect the elastic modulus of materials based on SiO2
- ПубликацияТолько метаданныеNUCLEAR-OPTICAL CONVERTERS FOR DETECTING INTENSE NEUTRON FIELDS ЯДЕРНО-ОПТИЧЕСКИЕ ПРЕОБРАЗОВАТЕЛИ ДЛЯ ДЕТЕКТИРОВАНИЯ СИЛЬНЫХ НЕИТРОННЫХ ПОЛЕИ(2021) Borisovich, B. P.; Vasilievich, S. V.; Marichev, G. V.; Stepanov, V. A.; Маричев, Глеб Владиславович; Степанов, Владимир Александрович© 2021 Obninsk Institute for Nuclear Power Engineering, National Research Nuclear University 'MEPhI'. All rights reserved.In the design of nuclear-optical converters (NOC) for detecting intense neutron fields (fluxes over 1·1015 cm-2·s-1), it is proposed to use hybrid gas ionization chambers (IC), in which electrical and optical neutron detecting methods are combined. For hybrid ICs, a technology is proposed for obtaining radiation-resistant and mechanically strong radiator materials capable of operating at temperatures up to 1000°C. This technology is based on solid-phase boron diffusion saturation of steel. It is shown that, at thermal neutron fluxes from 1·1010 n/(cm2·s), the integral intensity of argon luminescence as a result of ionization by α-particles and 7Li ions from layers of boride phases is sufficient for detection. The combination of optical and radiation properties of multicomponent fluoride glasses makes it possible to use them as condensed active substances of NOCs. Choosing the elemental and isotopic composition, it becomes possible to use fluoride glasses for multichannel neutron detection as well as to significantly simplify the procedure for separating gamma and neutron components of radiation under conditions of intense radiation fluxes. It has been experimentally shown that upon irradiation with a neutron flux of 1.1017 n/(cm2·s), the intensity of Nd IR luminescence in glasses based on zirconium fluoride (ZBLAN) increases in the presence of Gd, which interacts with neutrons.
- ПубликацияОткрытый доступA study of the mechanical and thermophysical properties of crystal matrices for the immobilization of high-level wastes(2024) Kuznetsov, I. V.; Zobkova, A. Yu.; Kalenova, M. Yu.; Stepanov, V. A.; Klemazov, K. V.; Степанов, Владимир АлександровичObjectives . The aim of the study was to confirm the compliance of the mechanical and thermophysical properties of titanate-zirconate mineral-like matrices intended for immobilization of the rare-earth-actinide fraction of high-level waste (HLW) with pyrochlore structures (Nd 2 ZrTiO 7 ) and orthorhombic titanate of rare earth elements (Nd 4 Ti 9 O 24 +TiO 2 ) with the Russian requirements for the final forms of radioactive waste sent for disposal. With regard to fractionated radioactive waste, this type of matrix is preferable when compared with conservative aluminophosphate and borosilicate glasses. This is due to larger capacity, and a better level of chemical, thermal, and radiation resistance. Methods. The synthesis of mineral-like matrices was carried out by remelting a granular precursor consisting of mineral-forming metal oxides and a solution imitating the rare earth-actinide fraction of HLW in an induction furnace with a cold crucible. The thermal diffusivity was determined by the laser flash method. The heat capacity of the matrix samples was measured by differential scanning calorimetry. Ultimate flexural and compressive strengths were determined using universal test machines. The elastic moduli (Youngў??s) were measured by the acoustic method. The temperature coefficients of linear expansion were determined using a high-temperature dilatometer. Results. The ultimate strength of the matrices (Nd 2 ZrTiO 7 ) and (Nd 4 Ti 9 O 24 +TiO 2 ) was found to be 150ў??179 and 20.6ў??57.8 MPa in compression and bending respectively. Youngў??s moduli vary from 3.7 ў?? 10 7 to 2.15 ў?? 10 8 kN/m 2 . With an increase in temperature from 50 to 500‚шC, the values of thermal conductivity have a pronounced tendency to decrease from 1.71 to 0.91 W/(mў??K). The temperature coefficients of linear expansion increase from 6.96 ў?? 10 ў??6 to 1.01 ў?? 10 ў??5 K ў??1 in the same temperature range. Conclusions. Comprehensive studies of titanate-zirconate mineral-like matrices show that their mechanical and thermal properties in certain cases significantly exceed the minimum requirements of regulatory documentation for the final forms of HLW.
- ПубликацияТолько метаданныеCurrent sources based on supercapacitors with β-radioisotopes(2020) Stepanov, V. A.; Alekseevich, C. V.; Grigorievich, P. Y.; Petrovich, L. V.; Степанов, Владимир Александрович© 2020 Obninsk Institute for Nuclear Power Engineering, National Research Nuclear University 'MEPhI'. All rights reserved.In asymmetric supercapacitors, electric charges are separated and accumulated during neutron irradiation. The paper deals with current sources with radioactive isotopes (CSRI) based on 100 F supercapacitors made by means of neutron activation of elements introduced into the electrodes of substances (BN or SrO). After neutron irradiation with a dose of up to 400 Gy, the supercapacitors turn into CSRI with a charging rate of up to 7.8 μV/day. The CSRI charging rate increases in proportion to the activation neutron dose up to 14 kGy. This is due to the production of β-active isotopes as a result of the reactions 14N(n, p)14C and 88Sr(n, γ)89Sr in the supercapacitor electrodes. An estimate of the radiation-induced charge accumulation rate, taking into account the energy released during β-decay of 14C and 89Sr, excludes the known charge separation mechanisms in a condensed medium due to the ionization and production of secondary electrons, electron-hole pair generation, etc. The electric charge separation and accumulation in CSRI occurs as a result of nonequilibrium thermoelectric phenomena in the near-electrode nano-regions. Nuclear reactions in nanoscale regions produce «temperature gradients» up to 105 K/nm. This leads to the «evaporation» of up to 1013 electrons from nanocrystallites at times of ~ 10-11 s.
- ПубликацияОткрытый доступThe physical modelling micro circulatory processes of biological tissues under the low-intensity IR-radiation(2020) Rozova, O. V.; Stepanov, V. A.; Степанов, Владимир Александрович© Published under licence by IOP Publishing Ltd.A physical modelling of the low-intensity IR-radiation influence on biological tissue was carried out. The deformation processes of biomembrane under the action of a non-uniform temperature field are studied. In addition to wavelength, pulse intensity and frequency the importance of pulse length has been shown for the effectiveness of laser therapy.
- ПубликацияТолько метаданныеRadiation hardening and optical properties of materials based on SiO2(2021) Stepanov, V. A.; Demenkov, P. V.; Nikulina, O. V.; Степанов, Владимир Александрович
- ПубликацияОткрытый доступCurrent sources based on supercapacitors with β-active isotopes(2020) Stepanov, V. A.; Степанов, Владимир Александрович; Kharanzhevskiy, E. V.; Lebedev, V. P.; Parshikov, Y. G; Chernov, V. A.
- ПубликацияТолько метаданныеPhysical Modeling of Low-Intensity IR Radiation Influence on Biological Tissues(2021) Stepanov, V. A.; Rozova, O. V.; Степанов, Владимир АлександровичThe influence of pulsed and continuous low-intensity infrared radiation on the morphology of HEK-293 cell cultures is compared. The effect of pulsed IR irradiation, which consists in increasing the optical contrast of cell boundaries, is proved. The mechanism of deformation of cell membranes during non-resonant light scattering is discussed.
- ПубликацияТолько метаданныеRadiation Changes in the Optical and Mechanical Properties of SiO2-Based Materials(2022) Nikulina, O. V.; Stepanov, V. A.; Степанов, Владимир Александрович© 2022, Pleiades Publishing, Ltd.Abstract: It is shown that radiation changes in the mechanical and optical properties of quartz glasses are of the same nature and are associated with the electric charge separation in the nano-inhomogeneous glass volume. The electric charge separation in glasses occurs up to the absorbed doses of the order of 1 MGy. The local separation of the electric charge due to the appearance of Coulomb forces leads to radiation Coulomb hardening of glasses and composites on their basis.
- ПубликацияТолько метаданныеCalorimetric and Spectroscopic Studies of Crystallization of Materials(2022) Klemazov, K. V.; Isaev, E. I.; Stepanenko, A. A.; Stepanov, V. A.; Исаев, Евгений Игоревич; Степаненко, Александр Александрович; Степанов, Владимир Александрович© 2022, Pleiades Publishing, Ltd.Abstract: The results of experimental determination of fluorozirconate glass crystallization temperatures by the methods of DSC and spectroscopy have been compared. It has been shown that the crystallization starting temperature, determined by an increase in the light scattering intensity, is 40° below the crystallization point, as seen by DSC. The effect of laser irradiation on the crystallization temperatures of glasses has been detected.