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  • Thermohydraulic Calculation of the Maximum Fuel and Water Temperature in the MAK-2 Facility
    Atom. Energy (IF 0.302) Pub Date : 2020-01-08
    O. Yu. Kochnov, V. V. Kolesov, A. S. Zevyakin, R. V. Fomin

    The maximum coolant temperature in the VVR-Ts MAK-2 loop facility for the production of 99Mo was analyzed. The calculations showed that adequate accuracy and temperature 96.3°C are attained using more than 106 grid elements. Taking into account the temperature dependence of the thermal conductivity of the uranium-containing layer increases the maximum temperature in this layer by more than 10%. When boiling, vaporization, and turbulence are taken into account the temperature at the egress from the coolant changes within the error range as compared with the use of a simplified model.

    更新日期:2020-01-08
  • 232 U Content Determination in Spent FA from Fast Reactor with a Uranium Load
    Atom. Energy (IF 0.302) Pub Date : 2020-01-08
    V. A. Nevinitsa, D. N. Kolupaev

    Experiments performed at the Mayak Production Assiciation to determine the 232U content in spent BN-600 fuel are analyzed. Calculations show that to within the limits of error the concentration largely agrees with the measured value, which makes it possible to use the calculations for a preliminary assessment of the 232U content in batches of uranium regenerated from reprocessed spent BN-600 FA.

    更新日期:2020-01-08
  • Safety Validation of the TUK-109T Large-Size Container for Transporting Spent Nuclear Fuel
    Atom. Energy (IF 0.302) Pub Date : 2020-01-08
    V. P. Solov’ev, A. A. Ryabov, V. I. Romanov, S. S. Kukanov, E. E. Maslov

    The design of the TUK-109T large-size container developed at the All-Russia Research Institute of Experimental Physics (VNIIEF) for transporting ampuls with bundles of spent fuel pins is described. The results of full-scale tests and three-dimensional simulation modeling for strength validation for mechanical actions occurring under normal operating conditions and during emergencies are presented. The computational validation of strength was performed in a three-dimensional formulation based on a finite-element model and a validated methodology of modeling dynamic deformation of structures, implemented in the highly parallelized LOGOS software. The validation of the methodology was performed by comparing numerical results with full-scale design tests. The computational prediction is shown to be highly accurate.

    更新日期:2020-01-08
  • IBR-2 Run Optimization Suggestions
    Atom. Energy (IF 0.302) Pub Date : 2020-01-08
    V. D. Anan’ev, I. B. Lukasevich, V. E. Popov, N. V. Romanova

    The operating time of the IBR-2 reactor depends on the fuel life. Currently, an IBR-2 run is formed at the cost of adding fresh FAs into the core without any reshuffling of the FA. In spite of its technological simplicity, this approach results in suboptimal fuel use because of high burnup non-uniformity. In the present work we propose optimizing a reactor fuel run by reshuffling FA during the run. This will give more uniform fuel burnup and increase the run time by almost 1/4 while limiting the ultimate burnup as compared with the conventional approach to run formation without reshuffling.

    更新日期:2020-01-08
  • Determination of the Circulation Intensity in a Centrifuge Rotor in the Enrichment of Isotopic Mixtures of Heavy Gases
    Atom. Energy (IF 0.302) Pub Date : 2020-01-08
    E. P. Potanin, L. Yu. Sosnin, A. N. Chel’tsov

    The circulation flow in a centrifuge during enrichment of isotopic mixtures of heavy gases is determined. Nickel tetraphosphine Ni(PF3)4 was used as the working substance to study the hydraulic and separative characteristics of a centrifuge. The relative circulation parameter m characterizing the efficiency of the multiplication of the primary effect is determined by comparing the computed dependences with the experimental results obtained in this work.

    更新日期:2020-01-08
  • Assessment of Kalinin NPP Impact on the Thermic Regime of the Cooling Reservoir and on the Littoral Climate
    Atom. Energy (IF 0.302) Pub Date : 2020-01-08
    V. A. Obyazov, A. Yu. Vinogradov, A. V. Kuchmin

    The results of an analysis of the thermal impact of the circulating cooling water discharged after cooling equipment in the Kalinin NPP on the thermic regime of the cooling reservoir and the climate in the littoral areas are presented. The impact was evaluated by comparing the hydrometeorological characteristics before the commissioning of the nuclear plant (1971–1983) and during its operation at full power (2013–2016) with similar characteristics in the background areas. It is shown that the impact of the Kalinin NPP on the littoral climate is very small and manifests only in a strip 200–300 m from the water edge. The main impact of the plant was to increase the water temperature in the cooling water reservoir and to increase evaporation from the surface of the reservoir.

    更新日期:2020-01-08
  • Possibility of Fast-Reactor Exportation Under an International Nuclear Non-Proliferation Regime
    Atom. Energy (IF 0.302) Pub Date : 2020-01-08
    A. V. Gulevich, V. M. Dekusar, A. N. Chebeskov, V. P. Kuchinov, N. P. Voloshin

    The exportation of fast reactors under an international nuclear weapons non-proliferation regime is discussed. Russian sodium fast-reactor technology has been successfully demonstrated and is in the commercialization stage. Fast reactors with lead as coolant are being developed in Project Breakthrough. In this connection, the possibility of exporting fast reactors becomes logical. The main criterion for such exports is competitiveness of the electricity produced taking the possibility of offering other, additional services into account. Other criteria that undoubtedly will influence the decisions made about exports are elements associated with the need for strict adherence to the international nuclear weapons non-proliferation regime. The basis of this regime is the nuclear weapons non-proliferation treaty. The IAEA system of safeguards plays a key role as a control element in verifying the obligations of non-nuclear states in the sphere of nuclear non-proliferation.

    更新日期:2020-01-08
  • Reconstruction of the Radioactive Contamination Occurring in the Environment in Primorskii Krai as a Result of a Nuclear Accident on a Submarine in Bukhta Chazhma
    Atom. Energy (IF 0.302) Pub Date : 2020-01-08
    A. A. Sarkisov, V. L. Vysotskii, D. A. Pripachkin

    The trajectory of a radioactive cloud formed above the Dunai Peninsula, Ussuriiskii Zaliv, Primorskii Krai, and the border area of China as a result of a nuclear accident in Bukhta Chazma in 1985 was reconstructed. The population–cloud contact time and the radioactive fallout density of the primary dose-forming radionuclides are estimated and the obtained results are compared with the admissible norms and the background. As a result of radioactive decay, scattering, and wash-out by atmospheric precipitation the volume activity of the dose-forming radionuclides in the ground layer of the atmosphere decreased by a factor of 105–106 over the passage time of the radioactive cloud starting from 1 km away from the site of the accident to the tip of Ussuriiskii Zaliv (60 km) and by a factor of 107–108 up to 400 km. The greatest contamination of Ussuriiskii Zaliv was noted in the uninhabited Cape Sedlovidnyi, located near the coastal radioactive track formed above the Dunai Peninsula after the accident. The radioactive fallout density increased by 3.8 kBq/m2 and the dose rate by 0.03 μSv/h, and in all other locations these indicators did not exceed 0.7–1 kBq/m2 and 0.01 μSv/h, respectively. These values turned out to be lower than the global fallout of 137Cs – 4.4 ± 0.7 kBq/m2 and the natural γ-background 0.14 ± 0.06 μSv/h. On the territory of Primorskii Krai and in the border area of China, the contamination did not exceed 0.01–1% of the background. At all stages of the accident, 60Co determined 95–99% of the long-time contamination of the environment.

    更新日期:2020-01-08
  • Subcriticality Measurement of Jackets with Spent FA VVER-1000 in a KhOT-1 Storage Facility Using the SKP-KhOT System
    Atom. Energy (IF 0.302) Pub Date : 2020-01-08
    S. A. Nikolaev, V. A. Chernov, A. V. Masterov, V. S. Volkov, S. G. Isaev, R. L. Ibragimov, M. A. Shul’ts, N. V. Kuzin, I. N. Seelev, S. R. Nevin

    The SKP-KhOT system for measuring subcriticality, making it possible to determine Keff of jackets with spent FA VVER-1000 during normal operation as well as design basis and beyond-design basis accidents, has been installed in the KhOT-1 storage facility at the Mining and Chemical Combine. The results of its tests have been recognized as positive; the design basis subcriticality of the studied jackets falls within the confidence interval of the measured value. It is shown that Keff of a jacket does not depend on its environment.

    更新日期:2020-01-08
  • Development of Environmental Monitoring in the Vicinity of Nuclear Energy Facilities
    Atom. Energy (IF 0.302) Pub Date : 2020-01-08
    M. L. Glinskii, A. V. Glagolev, S. L. Speshilov, V. A. Grachev, O. V. Plyamina, T. A. Evseenkova

    The automated system ASCRO developed and adopted in the nuclear industry for monitoring radiation conditions and on-site monitoring of subsoil status is continually improving, and the Rosatom State Corporation is continually expanding the sphere of activity of these systems. In the present article, the experience gained in the implementation of on-site monitoring of subsoil status in 2017 and the principles of its integration into the complex environmental monitoring system are expounded. Data on the development and integration of information-geoenvironmental packets of nuclear industry enterprises into the complex environmental monitoring system are presented.

    更新日期:2020-01-08
  • Characteristics of the Active Element of a Nuclear-Pumped Cadmium-Vapor Laser
    Atom. Energy (IF 0.302) Pub Date : 2020-01-08
    I. A. Denezhkin, P. P. D’yachenko, S. P. Stepanov

    The influence of the active-element characteristics on the efficiency of a cadmium-vapor laser pumped by uranium fission fragments was studied experimentally. The 441.6 nm laser radiation of the cadmium ion was studied. An aluminum tube with diameter ~15 mm and an inner coating of U3O8 with thickness 3 mg/cm2 served as the active element. The neutron source was the BARS-6 pulsed, fast, aperiodic, self-extinguishing reactor. A comparison of the efficiency of the laser with similar data previously obtained under the same conditions for a 48 mm in diameter active element with a ~10 mg/cm2 thick uranium metal coating shows that a three-fold reduction of the diameter of the active element and uranium coating thickness results in a 2.5-fold increase of the laser efficiency. This confirms the hypothesis of internal losses of laser radiation in the active element of a fission-fragment pumped laser which are due to the scattering of light by transverse sound waves of the gas density which appear during a pumping pulse because of the radial non-uniformity of the energy input.

    更新日期:2020-01-08
  • Integral Risk Impact on the Structural Makeup of the NPP System
    Atom. Energy (IF 0.302) Pub Date : 2020-01-08
    I. A. Rastorguev, T. D. Shchepetina

    An approach to developing the NPP system with the lowest integral risk determined according to the entire life cycle and the conjugate infrastructure is studied. The search for the optimal power series of reactors for the developing NPP system is formalized and presented as a multicriterion optimization problem: reduction of harm from various risk factors and construction cost for the specified system capacity. A solution is found with the aid of an evolutionary algorithm. Recommendations are made on the basis of the calculations for optimizing the power range of reactors that will make it possible to reduce the aggregate risk of NPP operation with different approaches to strategic planning.

    更新日期:2020-01-08
  • Neutronics Model of the IVG.1M Reactor: Development and Critical-State Verification
    Atom. Energy (IF 0.302) Pub Date : 2019-11-28
    R. A. Irkimbekov, L. K. Zhagiparova, V. M. Kotov, A. D. Vurim, V. S. Gnyrya

    The results of the verification of a model of the IVG.1M reactor based on experiments performed in 1990 and 2017 are reported. Startups of the reactor which are associated with its emergence into a critical state and measured values of the power, neutron flux density, and efficiency of the CPS [control and protection system] components were chosen for verification The isotopic composition of the fuel and the beryllium blocks formed by the time the first water-cooled process channels with high-enrichment fuel were extracted from the reactor (2017), was calculated. It was established on the basis of the verification results that the measured parameters agree well with the calculations. Currently, the model of the IVG.1M reactor is used for evaluating the post-conversion characteristics of the reactor as well as the parameters of planned experiments.

    更新日期:2019-11-28
  • Modular Testing of Dinitrogen Oxide (Nitrogen Hemioxide) Catalytic Decomposition Technology for Off-Gas Cleanup Systems for Brest Spent Nuclear Nitride Fuel Reprocessing
    Atom. Energy (IF 0.302) Pub Date : 2019-11-27
    S. A. Kulyukhin, A. A. Bessonov, I. A. Rumer, O. A. Ustinov, Yu. A. Voskresenskaya

    Dinitrogen oxide N2O (nitrogen hemioxide) is one of the harmful components of the off-gases during the reprocessing of spent nitride fuel. It enters the gas phase during the dissolution of nitride fuel in nitric acid and denitration of high-activity raffinate or the bottom solution from the evaporation of intermediate-level wastes. The preferred method of neutralizing it is high-temperature catalytic decomposition. Compositions based on γ-aluminum oxide coated with catalysts were found previously. One of the compositions was checked on a semi-industrial setup. The efficiency of N2O decomposition was studied as a function of temperature. It was established that almost complete decomposition occurs at 465–480°C. The specific rate of N2O decomposition at 425–480°C was found as a function of the initial concentration. It is shown that for constant initial concentration of N2O the specific decomposition rate is almost the same in the investigated temperature interval.

    更新日期:2019-11-28
  • Theoretical Basis for Using Hydrogen Reduction in Titanium Production
    Atom. Energy (IF 0.302) Pub Date : 2019-11-27
    B. O. Duisebaev, K. M. Baitasov, A. S. Mukusheva

    It is proposed that the cost of production of titanium sponge can be lowered by replacing the expensive and environmentally hazardous Mg-thermal conversion process by hydrogen reduction of titanium tetrachloride. The Kroll process, which is mainly used to produce titanium, is costly, which determines the high cost of titanium sponge. The reprocessing of titanium sponge into ingots requires large amounts of energy and specialized equipment. Preliminary research shows that hydrogen reduction of titanium with significant production cost reduction and enhanced environmental compatibility of the process is theoretically possible.

    更新日期:2019-11-28
  • Features of Mass Transfer of Noncondensable Gases by Primary Coolant of Nuclear Icebreaker Reactors
    Atom. Energy (IF 0.302) Pub Date : 2019-11-27
    V. E. Karnaukhov, V. S. Ustinov, D. S. Urtenov, Yu. B. Vorob’ev, Yu. B. Zudin, M. L. Lukashenko

    To study the characteristics of the mass transfer of noncondensable gases in the primary loop of the nuclear icebreaker reactors, models of the core and the up-core space were developed using the Relap5 (USA) and Fluent (USA) codes and modeling of interphase mass transfer and transport of the gas phase by the water coolant was performed on these sections. Spatial non-uniformity of the content of undissolved gases, which arises as a result of vapor-gas bubbles concentrating in the vortex structures of the flow and resulting in a significant reduction of their dissolution rate, was revealed. This must be taken into account in the analysis of the operation of the primary loop equipment of nuclear icebreakers (hydrogen absorption in the titanium alloys of steam-generator piping, nodular corrosion of the zirconium cladding of the fuel rods).

    更新日期:2019-11-28
  • Radiation Diagnostics of Pipelines and Equipment of Oil and Gas Production Complexes
    Atom. Energy (IF 0.302) Pub Date : 2019-11-27
    N. L. Kuchin, Yu. M. Vishnyakov, S. I. Emel’yanov

    An alert indicating the formation of salt deposits in the pipelines of oil and gas production complexes reduces the financial losses associated with the removal of these deposits and the loss of production. A method of taking into account the presence of the native radionuclide 232Th and its decay product 208Tl in the deposits is proposed for performing radiation diagnostics of pipelines. The appearance of the deposits is identified according to the 2.614 MeV γ-rays. The thickness of the deposits is determined according to the attenuation of the γ-rays from an external thorium dioxide source placed on the outer surface of a pipe. Calculations confirmed the presence of 1–2 mm thick deposits with probability 0.9 and a false positive rate of 0.01 in 1 h measurements with background 3 counts/sec. A 232Th-based external source with activity 105 and 106 Bq makes it possible to determine deposit thicknesses 2.5–3 and 1–2 mm, respectively, with measurement time 1 h and error about 15%.

    更新日期:2019-11-28
  • Industrial Trials of a Modernized Separation Part of Moisture Separators-Reheaters at the Leningrad and Smolensk NPP
    Atom. Energy (IF 0.302) Pub Date : 2019-11-27
    M. Yu. Egorov

    The purpose of this work is to compare industrial trials of modernized intermediate SPP-500-1 moisture separators-heaters of the K-500-65/3000 turbines in the No. 4 unit of the Leningrad NPP and the No. 1 unit of the Smolensk NPP. It was found that the distribution of the separated moisture along the perimeter and height of the steam space at the egress from the separation units is uniform in both NPP. A very small increase of the moisture concentration at the wall was obtained in individual apparatus at the Smolensk (No. 24) and Leningrad (No. 72) NPP. The flow rate of the separated material and the condensate of the warming steam, as measured on the Nos. 1 and 2 turbines of the Smolensk NPP, is close to that obtained on the Nos. 7 and 8 turbines of the Leningrad NPP. In the course of the industrial trials, it was shown experimentally that the moisture and flow rate are the same. This confirms the reliability of the results, which after modernization are close to the design-basis level.

    更新日期:2019-11-28
  • Improvement in the Technology for Extracting U–9%Mo Granules from Aluminum and Aluminum Alloy Based Dispersion Compositions
    Atom. Energy (IF 0.302) Pub Date : 2019-11-27
    I. V. Vasil’kov, A. Yu. Shadrin

    A classification by form and fraction of production turnovers with U–9%Mo fuel is made. The technology developed at the Institute of Physics and Power Engineering allowing unconditioned fuel rods and recovered material to be dissolved in a 10% solution of sodium hydroxide at temperatures 75–100°C is examined. The process developed for the Novosibirsk Chemical Concentrates Plant for extracting U–9%Mo granules from recovered material obtained in the production of dispersion-type fuel rods of the experimental IRT-3M fuel assemblies is examined. The optimal regimes for extracting U–9%Mo granules during the processing of recovered material obtained in production of dispersion fuel rods are determined and perfected. The basic chemical reactions involved in the process of dissolution of the aluminum matrix are presented. The U–9%Mo granules, initial and recovered from the dispersion fuel composition of the kernels and fuel rods, were investigated, the possible differences between them were determined, and the possibility of using recovered granules in the production of dispersion fuel rods was evaluated.

    更新日期:2019-11-28
  • Variant of Off-Gas Cleanup in Liquid Radwaste Vitrification
    Atom. Energy (IF 0.302) Pub Date : 2019-11-27
    O. A. Ustinov, S. A. Yakunin, T. V. Smelova

    A variant of a gas cleanup system for the vitrification of liquid radwaste is proposed. The characteristics of the gas flow formed upon inclusion of liquid high-level waste in borosilicate glass are examined. Two approaches to a gas cleanup system for radwaste vitrification are analyzed. A validated choice of gas cleanup equipment is made. The proposed gas cleanup system provides an efficient and compact way of cleaning up off-gases from the vitrification of high-level wastes formed, upon regeneration of spent nuclear fuel, from aerosols, volatile compounds of cesium, ruthenium, and iodine, and nitric oxide.

    更新日期:2019-11-28
  • Conditions and Initial Data for Reconstructing the Environmental Radioactive Contamination and Population Dose Loads Resulting from a Nuclear Accident on a Nuclear Submarine in Bukhta Chazhma
    Atom. Energy (IF 0.302) Pub Date : 2019-11-27
    A. A. Sarkisov, V. L. Vysotskii, D. A. Pripachkin, D. V. Dzama, R. Yu. Ignatov, K. G. Rubinshtein

    Refined initial data are presented for retrospective prediction and analysis of the radiation conditions in Primorskii Krai after a nuclear accident on a nuclear submarine on August 10, 1985 in Bukhta Chazhma. The initial and boundary conditions are substantiated, including sources of radioactive contamination of the environment, emission intensity of the determining dose-generating radionuclides, weather conditions, and particulars of the transport of the radioactive cloud above the ship repair yard, Dunai Peninsula, Zemlya Petra Velikogo, and Primorskii Krai territory. Substantiation is given for choosing the systems PARRAD and ROUZ for reconstruction of past events to predict the transport and spreading of radioactive substances in the atmosphere, making it possible to evaluate the radiation consequences of the accident for the population of Primor’ya and the adjoining part of China, including environmental contamination, taking into account actual data, numerical estimates, and reconstructed weather conditions for the period of the accident and on the days preceding and following it.

    更新日期:2019-11-28
  • Radwaste Volume from VVER-1000 Spent Fuel Reprocessing and Fractionation Variants
    Atom. Energy (IF 0.302) Pub Date : 2019-11-27
    V. A. Kashcheev, A. Yu. Shadrin, G. N. Rykovanov, N. D. Dyrda, I. R. Makeeva, D. V. Khmel’nitskii, P. N. Alekseev

    The possibilities of minimizing the volume of waste are examined for the reprocessing of spent nuclear fuel from VVER-1000 and the matrix material for high-level wastes. The analysis takes into account the designbasis isotopic composition of VVER-1000 spent fuel and the current normative base in the sphere of waste management. It is shown that deep underground disposal of radioactive wastes cannot be avoided at the present stage of development of the reprocessing technologies for the spent fuel from thermal reactors and with the existing legislation associated with the conditions of use of matrices for solidification of wastes and the conditions of waste disposal. Variant methods for decreasing the volume of underground disposal of radwaste are proposed.

    更新日期:2019-11-28
  • Kinetics of Radiation-Induced Optical Absorption Spectra in LPX-100, -200 Protective Glasses
    Atom. Energy (IF 0.302) Pub Date : 2019-11-27
    I. I. Dolgov, P. I. Dolgov, D. V. Shiyan, V. V. Kazakov, A. M. Gorchakov, A. G. Tsikanin, A. V. Churlyaev, V. N. Chernonozhkin, D. A. Linchevskii

    The results of studies of the kinetics of radiation-induced optical absorption spectra of commercially produced glasses LPX-100 and -200 (Lemer Pax Co., France) after γ-irradiation to 1 MGy in the wavelength range 320–1000 nm are reported. The restoration of light transmission was monitored for 120 days. The linear coefficients of attenuation of γ-radiation by glasses were measured using a KRONA-II-04 γ-spectrometer with OSGI standard radiation sources 60Co (1.173 and 1.333 MeV) and 137Cs (0.661 MeV). The experimental data make it possible to determine with adequate accuracy the applicability of the studied glasses under other conditions of irradiation. A brief comparative analysis of the results obtained for TK100 and TF103 glasses by other authors is given.

    更新日期:2019-11-28
  • Use of Neutron Scintillation Detectors as a Substitute for Helium-3 Counters in Radiation Monitors
    Atom. Energy (IF 0.302) Pub Date : 2019-11-21
    E. V. Ryabeva, V. V. Kadilin, V. A. Idalov

    The purpose of this work is to analyze the use of detecting materials in radiation monitors as well as the replacement of widely used 3H-based neutron counters by neutron-detection scintillation technology. The replacement of helium counters is a consequence of two factors: the lack of 3He and widespread use of 3He-based counters in safety equipment, such as volumetric neutron detectors. Selection criteria for evaluating promising technologies are used in this work, specifically, high absolute neutron detection efficiency – efficiency at least 1.5 counts in 1 sec in detecting 1 ng 252Cf at distance of 2 m in a 20 mm thick moderator and low sensitivity to γ-ray detection – γ-ray detection efficiency not exceeding 10–6 with irradiation by a 0.1 μSv/h γ-ray source. Since they can have a large sensitive area and high resolution, scintillation detectors are now being proposed as alternatives to helium counters. But it is necessary to find an optimal scintillator possessing simultaneously low sensitivity to γ-radiation and to choose an optimal method of measuring information. Promising neutron detection technologies based on the glasses Li2OSiO2:Ce3+, LiF/ZnS(Ag+), Li6Gd(BO3)3:Ce, Cs2LiYCl6(Ce) (CLYC) as well as EJ-254 boron-doped plastic are examined from the standpoint of the posed problems.

    更新日期:2019-11-21
  • Investigation of the Amplitude-Time Characteristics of a Penning Discharge in Miniature Ion Sources
    Atom. Energy (IF 0.302) Pub Date : 2019-11-18
    R. S. Rachkov, S. P. Maslennikov, D. I. Yurkov

    Ion sources based on Penning discharge cells are now widely used in small-size pulsed neutron generators of geophysical well-logging apparatus. The operating efficiency of the apparatus is associated with the amplitude and time parameters of the neutron pulse of the generator, which depend on the gas pressure, geometry of the electrode systems, and other factors. Therefore it is necessary to investigate Penning discharge regimes in the context of control and regulation of the working gas (hydrogen) pressure as well as to measure the amplitude-time characteristics of the discharge as a function of the periodic-pulse power supply parameters. The stable discharge ignition regimes in the ion source were determined experimentally, and it was shown that different discharge regimes exist. The operating regimes of ion sources with a descending voltage dependence of the discharge current were revealed at heightened gas pressure.

    更新日期:2019-11-18
  • Reactivity Determination with One Neutron Detector in a Transport-PWR Core
    Atom. Energy (IF 0.302) Pub Date : 2019-11-18
    A. V. Belin, M. A. Sosnin, A. G. Vasyatkin, A. A. Molodtsov, M. A. Kamnev, V. N. Vavilkin

    Neutronics measurements are regularly conducted during operation in order to evaluate the physical characteristics of the core. A nonstandard reactimeter connected to a backup neutron detector is used to perform the measurements. A calculation of the reactivity on the basis of the indications of a single detector results in distortion of the true value of the reactivity because of spatial effects. A method of increasing the accuracy of the reactivity calculations by taking account of the changes in the efficiency of the ionization chamber is proposed. Software for performing the required calculations has been developed. The correctness of the proposed solution was checked and confirmed by experiments performed on a critical stand at OKBM Afrikantov using the core of an icebreaker reactor.

    更新日期:2019-11-18
  • Investigation of the Influence of the Magnetic Field of a Well on the Neutron Tube of a Geophysical Apparatus
    Atom. Energy (IF 0.302) Pub Date : 2019-11-18
    R. S. Rachkov, A. Yu. Presnyakov, D. I. Yurkov

    The results of experimental studies of the effect of the magnetic field of the well casing on the operation of the gas-filled neutron tube used in the logging equipment are reported. The operation of the ion source was evaluated in terms of the parameters of the pulsed currents of charged particles recorded at the target of the neutron tube. Analysis shows that a longitudinal magnetic field, as compared with a transverse magnetic field, has a greater influence on the performance of the tube. Of the screening methods studied the one with a robust magnetic-steel housing for the equipment turned out to be most effective.

    更新日期:2019-11-18
  • Radiation Safety in Handling High-Level Wastes in Gremikha Village
    Atom. Energy (IF 0.302) Pub Date : 2019-11-18
    A. A. Zakharchev, V. V. Eremenko, I. N. Polishchuk, A. P. Varnavin, A. S. Danilovich, A. V. Korolev, A. V. Lemus, D. A. Lemus, V. A. Pavlov, V. N. Potapov, S. G. Semenov, S. V. Smirnov, B. S. Stepennov, A. K. Sukhoruchkin

    As part of the work on eliminating the nuclear legacy temporary storage facilities for high-level solid wastes were opened, radiometric inspection of the wastes was performed, wastes were sorted, control rods of ship reactors were identified in the wastes and removed, and spectrometric determination of the induced activity in each rod was made. Forty-four rods with activity totaling 1.35·1013 Bq were packaged and shipped to a long-term storage site. The activity distribution was determined from samples and will be taken into account in planning subsequent work on the handling of such wastes and picking the most appropriate type of packaging. The work was performed using remote-control machines in compliance with the standards and regulations for the radiation safety of personnel.

    更新日期:2019-11-18
  • Estimation and Prediction of the Population Irradiation Dose in the Vicinity of NPP with VVER-1200
    Atom. Energy (IF 0.302) Pub Date : 2019-11-18
    R. A. Mikailova, V. E. Nushtaeva, S. I. Spiridonov, E. I. Karpenko, V. V. Krechetnikov

    The dose loads from the natural and technogenic background to the population living in the vicinity of NPP with VVER-1200 in Kaliningrad Oblast were estimated on the basis of radioecological inspection data. The average yearly effective population irradiation dose from natural and technogenic radionuclides present in the environment is equal to 2.42 mSv. The population radiation impact from atmospheric emissions is predicted. The maximum dose load is ~1 μSv/yr and does not exceed the quota for radioactive emissions from NPP 10 μmSv/yr.

    更新日期:2019-11-18
  • Rotor Length Dependence of the Separative Power of a Gas Centrifuge
    Atom. Energy (IF 0.302) Pub Date : 2019-11-18
    O. E. Aleksandrov

    An analytical expression is obtained for the dependence of the maximum separative power of a centrifuge on the rotor length taking the feed flow into account. It is shown that the maximum separative power of a centrifuge is a nonlinear function of the rotor length.

    更新日期:2019-11-18
  • Enhanced Life Assurance for Ship Reactors
    Atom. Energy (IF 0.302) Pub Date : 2019-11-18
    D. G. Kresov, A. V. Kulikov, E. V. Olenskaya

    The reasons for the appearance of alternating deviations of the parameters in transient regimes, which negatively impact the resource characteristics of ship reactors, are investigated. A definitive physical mechanism and certain key phenomena responsible for the appearance and evolutionary character of the deviations of the defining parameters are revealed on the basis of qualitative analysis confirmed by computational studies. This assures the development of the most effective technical measures for reducing the dynamic overshoots in operating and in-design plants.

    更新日期:2019-11-18
  • Effect of Nitride Nuclear Fuel Structure and Phase Composition on Fuel-Rod Life
    Atom. Energy (IF 0.302) Pub Date : 2019-11-16
    M. P. Krivov, G. A. Kireev, A. V. Tenishev

    The behavior of mixed uranium-plutonium nitride fuel and uranium nitride was studied by means of thermogravimetry at high temperatures (to 2173 K) in a helium flow. The mass loss of the nitride samples was found in the low temperature range (<1773 K), which is not associated with decomposition of uranium or plutonium mononitrides. The mass loss occurs in two stages and is accompanied by the release of nitrogen. It is shown that nitride fuel can contain up to several percent of uranium sesquinitride U2N3, which decomposes in the indicated temperature range and can strongly affect pellet integrity and fuel-rod life during operation.

    更新日期:2019-11-17
  • Investigation of Americium Sorption from Model Liquid Radwaste Solutions Using TODGA-Based Solid-Phase Extractant
    Atom. Energy (IF 0.302) Pub Date : 2019-11-16
    N. V. Klochkova, A. A. Savel’ev, N. Yu. Pozdnyakova, S. S. Pisanenko, A. V. Anan’ev

    The purpose of this work is to investigate the sorption of americium from model solutions of liquid radwastes using modified solid-phase extracting agents based on TODGA as an alternative method of additional purification of liquid radwaste by removing transuranium elements by means of alkali precipitation. The kinetic parameters of uranium and americium sorption from highly saline weakly acidic (pH ~3.4) model solutions of liquid radwaste with americium content ~0.04 mg/liter were determined for three modified samples synthesized at VNIIKhT and one analog of a TODGA sample from the AXION Company. The time to equilibrium of all experimental samples in terms of americium is almost the same and equals ~240 min. The equilibrium concentration of uranium is reached in approximately 800 min. The salting-out effect in the extraction of uranium and americium from salt solutions is revealed, though this effect is much weaker for uranium than for americium. The most promising sorbent was determined – sample 7. Its distribution factor is 1.4 times higher than that of the AXION sample and the pair distribution factor Am/U is a factor of 2 higher.

    更新日期:2019-11-17
  • Experimental Thermophysical Studies in Validation of the Operability of Passive Safety Systems for Next-Generation VVER
    Atom. Energy (IF 0.302) Pub Date : 2019-11-16
    A. V. Morozov, A. P. Sorokin, D. S. Kalyakin, A. R. Sakhipgareev, A. S. Shlepkin

    The main results of experimental validation of the operability of passive core cooling systems of nextgeneration VVER are presented. It is shown that the residual heat release can be removed in 24 h on account of the operation of the second-stage water-storage system and the passive heat-removal system. As part of the validation of VVER-TOI passive safety systems the thermophysical properties of boric acid (density and viscosity) were measured experimentally with parameters characteristic for a reactor emergency. Empirical relations satisfactorily describing the experimental data are obtained.

    更新日期:2019-11-17
  • Simulation Systems in Experimental Development of a Space Nuclear Power System (Enisei SNPS)
    Atom. Energy (IF 0.302) Pub Date : 2019-11-16
    N. N. Ponomarev-Stepnoi, N. E. Kukharkin, V. V. Skorlygin, M. E. Annenkov

    The objectives and problems of modeling systems in developing nuclear thermionic power plants for use in space are discussed. The basic data of the modeling codes and systems developed in the process of creating the Enisei SNPS are presented. The principles of safe integration of a control digital computer into the control circuit of NPP are described and the results of experiments on the development of standard transient regimes in nuclear power tests are presented. The developed multicomputer distributed simulation system is presented, and the results of experimental testing of a scale model of the automatic control system in a wide range of operating modes are given.

    更新日期:2019-11-17
  • Economic Efficiency of Bringing Depleted Uranium into Enrichment
    Atom. Energy (IF 0.302) Pub Date : 2019-11-16
    Yu. G. Pavlov, Yu. A. Ul’yanin, D. A. Lazarev, V. V. Kharitonov

    The economic expediency of re-enrichment of depleted uranium with the possibility of subsequent disposal of secondary waste is evaluated. Three variants of bringing depleted uranium as a raw material into the production of natural-uranium equivalent and enrichment of uranium product are examined. Methods are proposed for evaluating the expediency of producing a natural-uranium equivalent from depleted uranium under different market conditions and in different operating regimes of the separation cascade as well as methods of evaluating the value of depleted uranium in the production of a natural-uranium equivalent and the production of enriched uranium product. It is shown that an effective method of bringing depleted uranium into enrichment is diversified production of enriched uranium product and not the production of a natural-uranium equivalent.

    更新日期:2019-11-17
  • 3D EVKLID/V2 Code Aided Simulation of Severe Accidents
    Atom. Energy (IF 0.302) Pub Date : 2019-11-16
    E. V. Usov, A. A. Butov, V. I. Chukhno, I. A. Klimonov, I. G. Kudashov, V. S. Zhdanov, N. A. Pribaturin, N. A. Mosunova, V. F. Strizhov

    When fuel rods melt during a severe accident, the movement of the structural and fuel materials along fuel assemblies can be spatially non-uniform, so that a three-dimensional thermohydraulic model is implemented in the EVKLID/V2 code as part of the HYDRA-IBRAE/LM module. The transport of the same sets of components and their mixtures as in the one-dimensional version of the HYDRA-IBRAE/LM module can be calculated in the model: liquid sodium, sodium vapor or vapor-gas mixture of sodium vapor and non-condensable gases, solid lead, liquid lead, solid uranium dioxide, liquid uranium dioxide, hard stainless steel, liquid stainless steel, steel vapor. The three-dimensional model is implemented in a cylindrical coordinate system, which makes it easier to include the geometric dimensions and parameters of a particular fuel assembly (number and diameter of fuel rods, lattice pitch, and others) and the core. A description is given of the basic system of equations describing the motion of the components of the destroyed core in the three-dimensional r–z–φ geometry, and its numerical realization. Examples of test calculations showing the serviceability of the model are presented.

    更新日期:2019-11-17
  • Investigation of PuF 3 and AmF 3 Solubility in 73LiF–27BeF 2 Melt
    Atom. Energy (IF 0.302) Pub Date : 2019-11-14
    A. A. Lizin, S. V. Tomilin, A. G. Osipenko, N. Yu. Nezgovorov, V. V. Ignat’ev, M. V. Kormilitsyn

    Using an experimental stand for studying the solubility of fluorides, measurements were performed at 550–700°C with step 50°C and the solubility of plutonium and americium trifluorides in melt with molar composition 73LiF–27BeF2 was calculated. Previously, such measurements were not performed for plutonium and americium trifluoride. The temperature dependence of the solubility of plutonium and americium trifluoride for the given salt system was constructed. The obtained solubility for plutonium trifluoride is appreciably higher than in a similar salt system with a higher content of beryllium difluoride. The obtained data on the solubility of americium and plutonium trifluoride can be used to select the minimum temperature of the fuel salt of a molten-salt reactor.

    更新日期:2019-11-14
  • Recovery of the Surface Density of Radionuclide Contamination of Soil from Aerogamma Survey Data
    Atom. Energy (IF 0.302) Pub Date : 2019-11-14
    D. V. Aron, S. L. Gavrilov, A. A. Kiselev, A. M. Shvedov

    The recovery of non-uniform surface contamination density from measurements of instrumental spectra performed by the airborne survey method is examined. An algorithm based on Tikhonov’s method of regularization is proposed for solving the inverse problem. The results of testing the chosen algorithm on model problems of recovering the 137Cs contamination of a soil surface in the form of spots with different activity and size are presented. The influence of the regularization parameter on the recovery error is analyzed, and the optimal values of the regularization parameter are obtained.

    更新日期:2019-11-14
  • Computational Modeling of Systems with Low Heat Fluxes
    Atom. Energy (IF 0.302) Pub Date : 2019-11-14
    A. M. Osipov, A. O. Gol’tsev, A. V. Il’in, A. M. Fedosov, L. N. Zakharova

    The results of computational modeling of experiments with heating of a water-filled and dewatered system are reported. The aim of the experiments was to test the computational methods used to analyze accidents in RBMK spent fuel storage, which is an example of a system with low heat fluxes. The calculations were performed using the RELAP5 code and a model specially developed for analyzing such experiments. It is shown that the RELAP5 code with the Reflood option gives acceptable results, but for lack of a description of surface evaporation in the code water level reduction in the calculations starts with a delay (after water boils) and occurs faster than in the experiment. When surface evaporation is taken into account by means of Balter’s empirical relation, the time dependence of the water level coincides with the experimental dependence. The variation of temperature at the control points of the heater is also close to the experiment. The heating of a dewatered system is described well by both models. Heat transfer by radiation from the heater to the vessel walls and into the ambient environment plays the main role.

    更新日期:2019-11-14
  • Influence of Rheological Characteristics of Concrete on the Stress-Strain State of NPP Containment
    Atom. Energy (IF 0.302) Pub Date : 2019-11-14
    V. N. Medvedev, M. I. Skorikova

    A comparative analysis is presented of the influence of the rheological characteristics of concrete on the stress strain state of NPP containment shells. It is based on creep and shrinkage tests performed on concrete, field observations, and calculations of the strains and stresses engendered in the reinforcement and concrete by the shrinkage and creep of concrete. The results showed discrepancies in the obtained data. For this reason, it is recommended that field data and detailed working models, in which the cross-section parameter and the pitch of the reinforcement rods correspond to the nominal values, be used in evaluating the stress-strain state of NPP containment under operational and accidental loads.

    更新日期:2019-11-14
  • Verification of a Mathematical Model for Calculating the Effective Irradiation Dose Rate from Contaminated Soil and Building Walls Taking Screening into Account
    Atom. Energy (IF 0.302) Pub Date : 2019-11-14
    D. V. Dzama, O. S. Sorokovikova

    A three-dimensional code for calculating the propagation of radioactive contamination under conditions of industrial development in the presence of atmospheric emissions is being developed at IBRAE RAS. The effective irradiation dose rate from a cloud, contaminated soil, and building walls is calculated on the basis of modeling. The screening of ionizing radiation by building walls is taken into account. The present work is devoted to verifying a method of calculating the effective irradiation dose rate due to contaminated soil and building walls. Two test problems are examined: with the contaminated surface of a cone-shaped building and a section of soil. It is concluded on the basis of the solution of problems that the accuracy of the method used in the three-dimensional computational code is acceptable.

    更新日期:2019-11-14
  • Investigation of Spatial Effects Accompanying Local Boiling of Coolant in VVER Core on the Basis of Neutron Flux Noise Analysis
    Atom. Energy (IF 0.302) Pub Date : 2019-11-14
    B. E. Shumskii, D. V. Vorob’eva, V. A. Mil’to, Yu. M. Semchenkov

    Situations with local boiling of the coolant become more likely when VVER-type power units are transferred to a heightened power level. In a VVER core, neutron flux detectors are not present in all FA. An important problem for evaluating the possibility of detecting local boiling in FA which are not equipped with detectors is the study of the spatial distribution of the change brought about in the neutron flux noise by local boiling of the coolant. The results of an investigation of the spatial distribution of the neutron flux noise initiated by fluctuations of the coolant parameters at the ingress into the core with non-equilibrium local surface boiling are reported. The sensitivity of the neutron flux noise in FA with no boiling to local boiling in neighboring FA is analyzed. The results could be helpful in analyzing the data recorded by the in-reactor noise diagnostics system in commercial operation in operating power-generating units.

    更新日期:2019-11-14
  • Radiative Heat Exchange in a Gas Cavity Above Reactor Core Melt During a Serious Accident
    Atom. Energy (IF 0.302) Pub Date : 2019-11-14
    D. D. Kamenskaya, A. S. Filippov

    A model of radiative heat-exchange, based on the Rosseland approximation, in a gas cavity was introduced into the HEFEST computational code designed for modeling the interaction of the core melt with NPP structures during a serious accident in VVER. This approach is admissible for optically dense gas and supplements the zonal heat exchange model, already existing in the code, for a cavity with a transparent gas. The conditions for using these two approaches in modeling radiative heat transfer at different stages of an accident are discussed. The numerical implementation of the diffusion model and its verification are described. The model was tested on the problem of radiative heat exchange during melt retention at the bottom of the vessel of a VVER-1000 reactor and the results are reported.

    更新日期:2019-11-14
  • Mathematical Model of Cadmium Distillation at the Stage of Pyrochemical Reprocessing of Spent Mixed Uranium-Plutonium Nitride Nuclear Fuel
    Atom. Energy (IF 0.302) Pub Date : 2019-11-14
    O. V. Egorova, N. V. Liventsova, S. N. Liventsov, O. V. Shmidt

    A mathematical model of the technological process of cadmium distillation at the stage of pyrochemical reprocessing of spent mixed uranium-plutonium nitride fuel for the purpose of studying the serviceability of and developing monitoring and process control systems is presented. The basic thermodynamic and kinetic characteristics and the principles of mathematical modeling of vacuum distillation of liquid mixtures, specifically, cadmium, are described. The requirements of the model and the assumptions are formulated. The information structure and mathematical description of the model were developed. Computational experiments were performed on the model and showed its serviceability and possibility of use for developing monitoring and process control systems.

    更新日期:2019-11-14
  • Measurement of 82,83,84 Kr( 3 He, xn ) 82 Sr Cross Sections in Kurchatov Institute U-150 Cyclotron
    Atom. Energy (IF 0.302) Pub Date : 2019-11-09
    V. A. Zagryadskii, S. T. Latushkin, T. Yu. Malamut, V. I. Novikov, A. A. Ogloblin, V. N. Unezhev, D. Yu. Chuvilin

    The activation method was used to determine the cross sections of the nuclear reactions 82Kr(3He, 3n)82Sr, 83Kr(3He, 4n)82Sr, and 84Kr(3He, 5n)82Sr in the 3He energy range 20–75 MeV on targets with highly enriched krypton isotopes. The results were used to calculate the 82Sr yield in a yield-optimized cascade target with 82,83,84Kr and initial 3He energy 75 MeV. The computed 82Sr yield was equal to 2.9 MBq/(μA·h), which makes it possible to count on the practical application of the method of 82Sr production based on the reactions 82,83,84Kr(3He, xn)82Sr in a cascade target.

    更新日期:2019-11-11
  • State and Role of Level-5 of NPP Protection-in-Depth System
    Atom. Energy (IF 0.302) Pub Date : 2019-11-09
    V. A. Panteleev, M. D. Segal’

    The topical problem of increasing scientific and technical support for level 5, associated with emergency planning and response, of the protection-in-depth system of NPP is examined. As severe accidents have shown, the greatest socioeconomic harm is associated with the excessive response by decision makers. There is a need to increase scientific-technical and methodological support for level 5 of the protection-in-depth system. It is shown that the use of risk-based approaches and the methodology of level-3 probabilistic safety analysis will make it possible to avoid scaling-up the socioeconomic consequences of radiation accidents and to optimize the available forces and means for mitigating the consequences of accidents.

    更新日期:2019-11-11
  • Evaluation of the Radionuclide Fallout Density on the Earth’s Surface in Different Variants of the Calculation of the Meteorological Dilution Parameters
    Atom. Energy (IF 0.302) Pub Date : 2019-11-09
    A. N. Perevolotskii, T. V. Perevolotskaya

    The aim of this work is to evaluate variants of the calculation of the average multiyear meteorological dilution parameters based on a Gaussian dispersal model for constant emissions. Three variants of the calculation of the meteorological dilution parameters which are distinguished by different degrees of detailing of the atmospheric stability categories and their characteristic wind speeds, which determines the difficulty and complexity of the calculations, are examined. It is shown that at distances >1000 m from the source of emissions all three computational variants give comparable results and can be used to estimate the radioecological conditions in the environment. The computational variant 1, which takes account of the realization of the atmospheric stability category and its corresponding gradations of wind speed, is the preferred option. It makes it possible to obtain more accurate estimates of the constant radioactive fallout density.

    更新日期:2019-11-11
  • Radioecological Studies in the Murmansk Littoral of the Barents Sea as Part of Environmental Monitoring in Radwaste Management
    Atom. Energy (IF 0.302) Pub Date : 2019-11-09
    G. V. Il’in, I. S. Usyagina

    The state of the marine environment in Motovskii Zaliv and Kol’skii Zaliv was studied within the framework of the monitoring and assessment of the radiation contamination of the Barents littoral. The indicated bodies of water as well as the Guba Zapadnaya Litsa and the Guba Andreeva as parts of the Motovskii Zaliv are included in the maritime transit shipment routes of spent nuclear fuel. The Guba Andreeva, where a radwaste storage facility is located, is considered to be the main source of radioactive contamination of the Barents littoral. The current radioecological status of the bodies of water used for transit operations is determined and the initial concentration level of radionuclides in the water and bottom deposits is established. It is shown that the radwaste storage facility in Guba Andreeva has the strongest impact on the radioecological state of the marine environment in Motovskii Zaliv. The obtained data can be regarded as necessary information for the development of maritime economic activity and comprehensive management of the littoral zones.

    更新日期:2019-11-11
  • 239 Pu–Be-Source Based Neutron Reference Fields
    Atom. Energy (IF 0.302) Pub Date : 2019-11-09
    V. N. Peleshko, E. N. Savitskaya, A. V. Sannikov, M. M. Sukharev, A. G. Muzoverov

    New neutron reference fields, based on a 239Pu–Be source, intended for increasing the accuracy of measurements of neutron dosimeters and radiometers in the IHEP accelerator complex are described. A Bonner SB-RSU-01 spectrometer was used to measure the spectra of the neutron reference fields. The BON95 code was used to reconstruct the spectra; the initial spectra for the iteration procedure were determined by parameterization or by a calculation using the FAN15 code. Good agreement was obtained between the neutron spectra and the integral characteristics of the reference fields reconstructed by the two methods.

    更新日期:2019-11-11
  • Correction to: Development of a Radiotherapy System Based on 6 MeV Linac and Cone-Beam Computer Tomograph
    Atom. Energy (IF 0.302) Pub Date : 2019-11-08
    I. I. Rod’ko, G. A. Sarychev, P. V. Balakirev, T. V. Bondarenko, I. L. Dergacheva, A. S. Evteev, S. N. Kovalev, S. A. Koloskov, T. A. Krylova, T. K. Lobzhanidze, S. A. Polikhov, V. P. Smirnov, G. B. Sharkov, G. E. Gorlachev, I. A. Gulidov, S. A. Ivanov, A. D. Kaprin, Yu. S. Romanko, E. V. Khmelevskii, L. Yu. Ovchinnikova, V. I. Shvedunov, N. V. Shvedunov, D. V. Cherednichenko

    The 15th author’s name should read I. A. Gulidov. The caption for Fig. 3 on page 336 should read

    更新日期:2019-11-11
  • Correction to: Calculation of the Dose Distribution Near the Gantry of a Radiotherapy System
    Atom. Energy (IF 0.302) Pub Date : 2019-11-08
    T. V. Bondarenko, S. A. Polikhov, V. P. Smirnov, A. S. Kurilik, L. Yu. Ovchinnikova

    In Fig. 5 on page 341, the units for the X and Z axes should read cm. In Fig. 6 on page 341, the units for the X and Y axes should read cm.

    更新日期:2019-11-11
  • Change of the External Flows of a Separating Cascade to Shorten the Duration of a Transient Process
    Atom. Energy (IF 0.302) Pub Date : 2019-11-08
    A. A. Orlov, A. A. Ushakov, V. P. Sovach

    A transient process is studied for the example of obtaining in a cascade of gas centrifuges germanium enriched in 72Ge to 50%. The nature of the effect of the cascade flows on the concentration dynamics of the isotopes and duration of the transient process is determined. The conditions under which the accumulation of the desired isotope in the cascade is accelerated and the duration of the transient process is decreased are shown.

    更新日期:2019-11-11
  • Cascades with Flow Expansion for Simultaneous Concentration of Intermediate Components
    Atom. Energy (IF 0.302) Pub Date : 2019-11-08
    D. N. Fomin, A. Yu. Smirnov, G. A. Sulaberidze, A. R. Mustafin

    A cascade scheme allowing two intermediate-mass isotopes to be concentrated in a single cascade above the maximum admissible concentrations at the outputs of ordinary cascades is proposed. A cascade with two flow expansions and two additional product flows is used for this. For the example of a mixture of tungsten isotopes, it is shown that the concentrations of 183W and 184W can be increased simultaneously up to 70 and 80%, respectively. In addition, additional product flows can be equal to 50–70% of the primary (end) product flow of the cascade.

    更新日期:2019-11-11
  • Radiolysis of 232,234 U-Enriched Regenerated-Uranium Hexafluoride at the Temporary Storage Stage in a Separation Plant
    Atom. Energy (IF 0.302) Pub Date : 2019-11-08
    I. A. Belov, A. V. Grol’, V. A. Nevinitsa, O. Yu. Poveshchenko, A. Yu. Smirnov, G. A. Sulaberidze

    The results of modeling of the radiolysis of uranium hexafluoride at the stage of its temporary storage in a separation plant are reported. Regenerated uranium, which is enriched with 232,234U, being the strongest α-emitting isotopes, was examined as an example. The radiochemical yield of UF6 decomposition was determined approximately from the experimental data. It is shown that the concentration of uranium pentafluoride formed upon radiolysis of uranium hexafluoride is a factor of 107 lower, which, neglecting impurities, makes it possible to assume that the hexafluoride as a whole retains its properties.

    更新日期:2019-11-11
  • Prospective Micro-Encapsulated Fuel with Silicon Carbide Protective Coat
    Atom. Energy (IF 0.302) Pub Date : 2019-11-08
    A. V. Beleevskii, I. E. Golubev, E. V. Klyukin, Z. Sh. Nikuradze, K. A. Pozdnyakov, M. V. Yudin

    A promising direction in the development of the next-generation fuel is the development of fully ceramic micro-encapsulated fuel (FCM). Such fuel has proven itself well in high-temperature gas-cooled reactors (HTGR). The fuel consists of 200–700 μm in diameter microspheres made from the fuel material coated with a multi-layer ceramic coating. The standard four-layer coating used in HTGR reactors consists of three layers of pyrolytic carbon and a layer of silicon carbide. The technology developed at VNIINM for fabricating protective coatings consisting of only silicon carbide makes it possible to enhance the radiation and heat resistance of the coatings and, correspondingly, increase the fuel life. Calculations have confirmed the main advantages of the micro-encapsulated fuel with a silicon carbide coating over the conventional TRISO coatings. The use of such microfuel elements opens up the possibility of developing fuel elements capable of retaining fission products both under normal operating conditions and in design-basis and beyond-design-basis accidents. Variants of the design of rod-shaped accident-tolerant fuel (ATF) for water-cooled reactors based on micro-encapsulated fuel with silicon carbide coatings and cladding comprised of a composite of the type SiC–SiC are considered.

    更新日期:2019-11-11
  • Approaches to Developing a Small Nuclear Power Plant Based on a Gas-Cooled Reactor
    Atom. Energy (IF 0.302) Pub Date : 2019-11-08
    Yu. G. Dragunov, V. V. Kudinov, D. G. Kulikov

    The concept of a small gas-cooled reactor for the Brayton cycle using reactor technologies, design solutions, and existing experience of NIKIET is proposed. The concept is based on the optimal use of existing materials in the design and implements the principles of universality, modularity, and compactness. Variants of the reactor design, design of the transport lock system, cooling channel of the critical components of the reactor vessel, and radiation protection are presented.

    更新日期:2019-11-11
  • Impact of Deferred SNF Financial Liabilities on NFC Backend Strategy
    Atom. Energy (IF 0.302) Pub Date : 2019-11-08
    A. V. Gurin, P. S. Teplov, E. G. Pogodina

    The specifics of an NPP operating organization’s deferred financial liabilities for SNF management and the impact on them of the infrastructure formation rate at the final stage of the NFC are examined. The financial aspects of the problem and the current state and plans for the formation of an industrial complex for SNF management are examined. As an example of a computational analysis, it is shown that shifting the commissioning dates for the spent fuel reprocessing facilities greatly affects the deferred liabilities and, correspondingly, the financial stability of the company. Analysis of the dynamics of the change in the liabilities over time determines the importance of creating and managing a special reserve fund, taking into account the attendant risks of increasing the NPP’s cost of electricity production as a result of an increase in the current expenses for spent fuel management. Conclusions are drawn about the effect of individual reactor technologies on the structure of the deferred liabilities.

    更新日期:2019-11-11
  • Volume-Localized Quantum Levels in Charged Fullerenes
    Atom. Energy (IF 0.302) Pub Date : 2019-10-17
    R. V. Arutyunyan, A. V. Osadchii

    The existence of a system of short-lived, discrete, volume-localized, electronic, quantum levels in positively charged fullerenes is shown theoretically and numerically for the example of the fullerenes C60. The results of three-dimensional calculations performed using the QuantumEspresso package are presented. The structures of the quantum levels in charged fullerenes were calculated numerically in a wide range of transitions from 4 eV for the fullerene \( {C}_{60}^{+ 1} \) to 40 eV for the fullerene \( {C}_{60}^{+ 1} \). The results confirm previous theoretical work on the possible existence of single-particle excited electronic states localized in the volume of positively charged fullerene C60. Thus, the electrons captured in these discrete levels of fullerene form a kind of short-lived superheavy pseudoatom in which the electrons are localized inside a positively charged spherical nucleus with atomic mass 240 a.u. for C20 and 720 a.u. for C60. In conclusion, the possibility of generating coherent radiation on these transitions is discussed.

    更新日期:2019-11-04
  • Distillation of Lithium Chloride From the Products of Uranium Dioxide Metalization
    Atom. Energy (IF 0.302) Pub Date : 2019-10-12
    A. B. Salyulev, A. V. Shishkin, V. Yu. Shishkin, Yu. P. Zaikov

    The possibility of purifying the metalized products of pyrochemical operations by removing the electrolyte by distilling off lithium chloride is checked experimentally. This study is performed in connection with the development of promising variants of an industrial method of metalizing uranium dioxide, which is the main component of the spent nuclear fuel after its voloxidation. The electrolyte was distilled from metalized pellets and powders based on uranium dioxide with their continuous evacuation at 700–900°C. It was found that the main component of the sublimates is lithium chloride; the content of rare-earth elements and uranium is very low. The distillation regimes where 98.8–99.9% of the LiCl can be removed from the metalized products were determined.

    更新日期:2019-11-04
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