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Morozov A.V.,Obninsk Institute of Physics and Power Engineering | Sakhipgareev A.R.,Obninsk Institute of Physics and Power Engineering
Izvestiya Wysshikh Uchebnykh Zawedeniy, Yadernaya Energetika | Year: 2017

The paper presents the results of experimental study of the effect of contact condensation of steam-gas mixture on the operation of VVER passive safety systems and the steam generator in emergency condensing mode. The contact condensation takes place when subcooled fluid is supplied in the accumulator tank of VVER reactor facility passive core flooding system (the HA-2 system) in the presence of non-condensable gases. Water supplied to the second stage of hydro accumulators can be used for increasing the operating time of the VVER steam generator in the emergency condensing mode and ensuring longer core cooling. Low liquid outlet velocity (less than 1 m/sec), necessitated to ensure safety systems operation in passive mode constitutes the distinguishing feature of the investigated processes. The experiments were performed on the test facility with the parameters specific to the primary circuit of the reactor facility within 24 hours after the accident initiation for different concentrations of gas in the steam-gas mixture. Nitrogen and helium, which replaces hydrogen, were used as the non-condensable gases. It was established as the result of the experiments that the increase of concentration of non-condensable gas in the volume the HA-2 hydro accumulator model up to 45% leads to the reduction of intensity of contact condensation of steam from the steam-gas mixture by ∼29% in the experiment with nitrogen and by ∼57% in the experiment with helium. The obtained experimental data can be used for numerical simulation of emergency processes in the VVER reactor facility during operation of passive safety systems taking into account the removal of steam-gas mixture from steam generator by supplying the subcooled liquid jet into the volume of second stage HA-2 accumulator tanks.

Pshakin G.M.,Obninsk Institute of Physics and Power Engineering | Moseev P.A.,Obninsk Institute of Physics and Power Engineering | Korobeynikov V.V.,Obninsk Institute of Physics and Power Engineering | Moseev A.L.,Obninsk Institute of Physics and Power Engineering
Izvestiya Wysshikh Uchebnykh Zawedeniy, Yadernaya Energetika | Year: 2017

As of the present moment enormous amounts plutonium were accumulated during the period of development of the Soviet (Russia) nuclear program in spent fuel of reactors of different types - power, research and mobile. Issues associated with future fate of the accumulated plutonium (and plutonium which is currently being accumulated) such as long-term storage, burial or subsequent use as reactor fuel with closing nuclear fuel cycle, require exact knowledge about the places where plutonium is stored, its quantities and conditions at any required time moment. Existing nuclear material control and accounting system does not allow obtaining the required information. The present study is dedicated to the examination of further development of the structured relational database for civil plutonium in Russia (SRDBCP) development of which was initiated in 2013 and which would allow preparing input data for implementation of systems analytical studies for substantiating the decision taken on the future use of civil plutonium in Russia. The first priority task of the present study is the possibility of selection of technological batches of extracted plutonium for manufacturing BN-800, BREST and BN-1200 fast reactor core loads. At the same time the SRDBCP can be used as well for addressing wider scope of problems associated with substantiation of closed nuclear fuel cycle. Co-operation with such powerful software complexes as CYCLE will allow performing high-accuracy calculations from a single workplace and within compressed timeframe. Computer mechanisms for processing and transformation of data, mechanisms of interaction with computational software complexes (CYCLE) - preparation of input data for calculations of scenarios of development of nuclear power generation in Russia and in the world based on thermal and fast nuclear reactors, including for closing the nuclear fuel cycle were developed as the result of continued work with SRDBCP.

Tolokonnikov S.V.,Moscow Institute of Physics and Technology | Kamerdzhiev S.,Obninsk Institute of Physics and Power Engineering | Krewald S.,Jülich Research Center | Saperstein E.E.,RAS Research Center Kurchatov Institute | Voitenkov D.,Obninsk Institute of Physics and Power Engineering
European Physical Journal A | Year: 2012

The quadrupole moments of odd neighbors of semi-magic lead and tin isotopes and N = 50, N = 82 isotones are calculated within the self-consistent Theory of Finite Fermi Systems based on the Energy Density Functional by Fayans et al. Two sets of published functionals are used to estimate systematic errors of the present self-consistent approach. They differ by the spin-orbit and effective tensor force parameters. The functional DF3-a leads to quadrupole moments in reasonable agreement with the experimental ones for most, but not all, nuclei considered. © 2012 SIF, Springer-Verlag Berlin Heidelberg.

Borzov I.N.,Obninsk Institute of Physics and Power Engineering | Saperstein E.E.,RAS Research Center Kurchatov Institute | Tolokonnikov S.V.,RAS Research Center Kurchatov Institute | Neyens G.,Catholic University of Leuven | Severijns N.,Catholic University of Leuven
European Physical Journal A | Year: 2010

Dipole magnetic moments of several long isotopic chains are analyzed within the self-consistent finite Fermi system theory with exact account for the pairing and quasiparticle continuum. The momentum dependence of the spin-isospin Landau-Migdal amplitude g′ is taken into account. This dependence was introduced previously to describe high-energy electron magnetic scattering. New moment data for nuclei far from the β-stability valley are included in the analysis. For a number of semi-magic isotopes of the tin and lead chains a good description of the data is obtained, with an accuracy of 0.1-0.2μN. A chain of non-magic isotopes of copper is also analyzed in detail. © 2010 SIF, Springer-Verlag Berlin Heidelberg.

Kalashnik M.V.,Obninsk Institute of Physics and Power Engineering | Chkhetiani O.G.,Russian Academy of Sciences
Fluid Dynamics | Year: 2016

The problem of the stability of an isolated jet flow and two counter-streaming jet flows in a rotating shallow-water layer is considered. These flows are described by exact solutions of the Charny–Obukhov equation with one or two discontinuities of the potential vorticity, respectively. The isolated jet flow is shown to be stable. For the system consisting of two jet flows the dependence of the characteristics of the unstable wave modes on a geometric parameter, namely, the ratio of the spacing between the jet axes to the deformation radius, is determined. On the basis of the contour dynamics method a weakly-nonlinear model of the longwave instability is developed. © 2016, Pleiades Publishing, Ltd.

Rezvykh K.A.,Obninsk Institute of Physics and Power Engineering | Romanov V.A.,Obninsk Institute of Physics and Power Engineering
24th Russian Particle Accelerator Conference, RuPAC 2014 | Year: 2014

New effective technique of conditioning of gaseous insulation of electrostatic accelerator is described. To achieve stable breakdown voltage, accelerator conditioning procedure would take 7-8 hours (volume of pressure tank is 93 m ). Three methods of monitoring cleanness of gaseous insulation are proposed. © 2014 CC-BY-3.0 and by the respective authors.

Raskach K.F.,Obninsk Institute of Physics and Power Engineering
Physics of Atomic Nuclei | Year: 2012

In multigroup calculations of reactivity and sensitivity coefficients, methodical errors can appear if the interdependence of multigroup constants is not taken into account. For this effect to be taken into account, so-called implicit components of the aforementioned values are introduced. A simple technique for computing these values is proposed. It is based on the use of subgroup parameters. © 2012 Pleiades Publishing, Ltd.

L'vova E.M.,Obninsk Institute of Physics and Power Engineering | Chebeskov A.N.,Obninsk Institute of Physics and Power Engineering
Izvestiya Wysshikh Uchebnykh Zawedeniy, Yadernaya Energetika | Year: 2016

Nuclear fuel cycle of fast reactors contains material which is directly or with some additional processing can potentially be used to manufacture a primitive nuclear explosive device or even for the production of powerful nuclear weapons. When considering the problem of non-proliferation of nuclear weapons and nuclear terrorism it is customary to apply to such materials the notion of attractiveness, in other words, to evaluate the potential use of these materials in undeclared activities. The attractiveness of nuclear materials in the first turn is estimated according to their intrinsic neutron-physical properties. The value of critical mass is a key characteristic in the choice of nuclear material that can be used to manufacture nuclear explosive devices. In addition to critical mass, important characteristics of nuclear materials are neutron background and heat generation. The high neutron background will inevitably lead to the premature start of the chain fission reaction - predetonation, which practically excludes the possibility of nominal energy yield. Significant level of heat generation of nuclear material complicates its treatment, but the main factor is the influence of high temperature on the degradation of chemical explosives, which is directly adjacent nuclear material and at a sufficiently high temperature of nuclear material the chemical explosive loses its properties and breaks the performance of a nuclear charge. This paper presents the results of the study of the attractiveness of different types of fuel compositions according to their neutron-physical properties as applied to the fuel cycle of sodium fast reactor of high capacity (BN-1200 type) for different options of the reactor start loading and reaching steady-state conditions. The objects of the study are the simplest systems in the form of spherical assemblies containing the fuel compositions of the fast reactor BN-1200 type without reflectors and surrounded by elementary neutron reflectors. Critical state is defined for each such a system and for this state main neutron-physical properties are calculated.

Manturov G.N.,Obninsk Institute of Physics and Power Engineering | Nikolaev M.N.,Obninsk Institute of Physics and Power Engineering
Izvestiya Wysshikh Uchebnykh Zawedeniy, Yadernaya Energetika | Year: 2016

Equation transport of neutron and gamma radiation in the energy, essential in the calculations of fast reactors and radiation shielding, does not contain any significant approximations - the accuracy of its solution is determined almost entirely accurate knowledge of the characteristics of the interaction of radiation with matter and, only partially, of correctness of computational techniques. Providing computational codes with reliable data about the characteristics of the interaction is the responsibility of the sectoral metrological service. Bringing methods of using these characteristics in the calculation of radiation fields in accordance with the state of knowledge of these characteristics should be one of the most important tasks in developing a new generation of codes. Hereafter the priorities in this direction are considered that must be addressed when developing a new generation of constants supplying software for fast reactor calculations as it is a unified system ABBN-2020 of multigroup neutron nuclear physics constants obtained on the basis of files ROSFOND national neutron data library. At the same time, along with the creation of a perfect system to ensure nuclear constants calculations, a considerable attention must be paid to the development and creation of methodology and computer code system for the evaluation and ranking of the estimated errors in the calculation of nuclear reactors in order to be concentrated on the most important issues. Creating of a new generation unified nuclear constants support system ABBN-2020 and its implementation in the design codes will not only ensure uniformity neutron constants preparation procedures, which will increase the reliability of their verification, but also improve the accuracy and reliability of predictions of the most important characteristics of the designed reactors, providing their license purity, competitiveness and independence from foreign developments.

Albutova O.I.,Obninsk Institute of Physics and Power Engineering | Lukyanov D.A.,Obninsk Institute of Physics and Power Engineering
Izvestiya Wysshikh Uchebnykh Zawedeniy, Yadernaya Energetika | Year: 2015

The problem of determining the background of indications of measuring channels of the sector control tightness claddings (SSKGO) (evidence in the absence of the defect), which significantly depend on the location of the control points and the operational parameters of the reactor is relevant for fast reactors. The ability to predict the estimated background opens up prospects for further development of the sector CLC, improve its technical and metrological characteristics. The dependence of readings SSKGO BN-600 on the operational parameters and the development of a regression model predicting SSKGO background readings. Process performance. 1) Formation of the list of parameters of the regression model for determining background level measuring channel SSKGO. Along with the power of the reactor, the temperature in the detection unit (DB) and the time to start mikrokampanii in the model included the estimated value of the temperature outside of the database, which is proportional to the temperature increment in the database. 2) Determination of the coefficients of the regression model was performed by least squares (OLS) using stepwise regression with the sequential addition of para-meters. The criterion for inclusion of a parameter in the model was to reduce the value of the average approximation error e and normalization of residual distribution model. Data processing was carried out using MS Excel, MS Access, VBA. Modeling results show that all parameters are statistically significant. In the prediction error of the model developed SSKGO background readings in all areas given one-governmental mikrokampanii reactor BN-600 is less than 1%, which meets the original requirements. The research background depending on the operational parameters of the reactor have scientific novelty - earlier similar studies have not been published, and practical significance. Upon completion of testing the model developed at enhancing the operational data, will decide on the implementation of the technique as part of SSKGO rectors of the BN-600 and BN-800. © Pioro I.L., Kirillov P.L., 2015.

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