Physical and Technical Center

Nizhniy Novgorod, Russia

Physical and Technical Center

Nizhniy Novgorod, Russia

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Seleznev V.E.,Physical and Technical Center | Aleshin V.V.,Physical and Technical Center | Pryalov S.N.,Physical and Technical Center
Science and Technology of Nuclear Installations | Year: 2011

The paper describes one of the variants of mathematical models of a fluid dynamics process inside the containment, which occurs in the conditions of operation of spray systems in severe accidents at nuclear power plant. The source of emergency emissions in this case is the leak of the coolant or rupture at full cross-section of the main circulating pipeline in a reactor building. Leak or rupture characteristics define the localization and the temporal law of functioning of a source of emergency emission (or accrued operating) of warmed up hydrogen and steam in the containment. Operation of this source at the course of analyzed accident models should be described by the assignment of the relevant Dirichlet boundary conditions. Functioning of the passive autocatalytic recombiners of hydrogen is described in the form of the complex Newton boundary conditions. Copyright © 2011 Vadim E. Seleznev et al.


Seleznev V.E.,Physical and Technical Center | Kiselev V.V.,Physical and Technical Center
Advances in Safety, Reliability and Risk Management - Proceedings of the European Safety and Reliability Conference, ESREL 2011 | Year: 2012

The paper describes a method for optimization of discrepancies in natural gas supply to consumers, who receive gas from gas distribution ring pipelines. Numerical monitoring makes it possible to obtain computational estimates of actual gas deliveries over given time spans and to estimate their difference from corresponding values reported by gas consumers. Such estimation is performed using a computational fluid dynamics simulator of gas flows in the gas distribution system of interest. Numerical monitoring of the discrepancy is based on a statement and numerical solution of identification problem of a physically proved gas dynamics mode of natural gas transmission through specified gas distribution networks. The identified mode parameters should have a minimum discrepancy with field measurements of gas transport at specified reference points of the simulated pipeline network. © 2012 Taylor & Francis Group.


Seleznev V.,Physical and Technical Center | Aleshin V.,Physical and Technical Center | Pryalov S.,Physical and Technical Center
11th International Probabilistic Safety Assessment and Management Conference and the Annual European Safety and Reliability Conference 2012, PSAM11 ESREL 2012 | Year: 2012

The paper describes one of the variants of mathematical model of a fluid dynamics process inside the containment, which occurs in the conditions of functioning of spray systems at severe accidents at nuclear power plant. The source of emergency emissions in this case is the leak of the heat carrier or rupture at full cross section of the main circulating pipeline in a reactor building. The leak or rupture characteristics define the localization and the temporal law of functioning of a source of emergency emission (or accrued operating) of warmed-up hydrogen and steam in the containment. Functioning of this source at the course of analyzed accident models is reasonably to carry out by the assignment of the relevant Dirichlet boundary conditions. Functioning of the passive autocatalytic recombiners of hydrogen is described in the form of the complex Newton boundary conditions, which parameters of changes in time are determined by using a wellknown principle of submodeling. The work of the heat exchangers-condensers is simulated by the Newton boundary conditions, which is similar to the boundary conditions on the walls of an inner protective shell with its steel facing taken into account. The suggested in the paper models are oriented on their application by the engineers who are dealing with designing of nuclear power plants and who do not have power computers. One of the obligatory conditions at the development of mathematical model was the correct description of processes of functioning of a spray system and a heat removal in the coated with the steel walls of the containment taking into consideration the condensation of steam on it. The main functions of spray system are the decrease of pressure inside of the containment at accident and prevention of formation of explosive hydrogen/steam/air clouds in the containment rooms. Combustion risk of clouds in this case is estimated by the well-known Shapiro diagram.


Seleznev V.,Physical and Technical Center | Kiselev V.,Physical and Technical Center | Pryalov S.,Physical and Technical Center
Applied Mechanics and Materials | Year: 2011

The article describes algorithm for optimization of discrepancies in natural gas supply to consumers. Numerical monitoring makes it possible to obtain computational estimates of actual gas deliveries over given time spans and to estimate their difference from corresponding values reported by gas consumers. Mathematical analysis of the discrepancy is based on a statement and numerical solution of identification problem of a physically proved gas dynamics mode of natural gas transmission through specified gas distribution networks. The identified mode parameters should have a minimum discrepancy with field measurements of gas transport at specified reference points of the simulated pipeline network. © (2011) Trans Tech Publications.


Aleshin V.V.,Physical and Technical Center | Seleznev V.E.,Physical and Technical Center
Contemporary Engineering Sciences | Year: 2014

The paper describes an approach to the numerical analysis of response of nuclear power plant buildings including soil-structure interaction effects. A reinforced concrete structure of an NPP reactor building under operating and seismic loadings is considered. The simulated seismic load corresponds to a maximum designed earthquake of magnitude 7 (the peak ground surface acceleration is 0.12 g). The numerical analysis was performed by the finite element method in a 3D nonlinear statement using the FEM-programs ANSYS and LS-DYNA. Review of the numerical analysis results demonstrated that the presented technique can be successfully applied to seismic design of NPP structures. © 2014 Vladimir V.Aleshin and Vadim E. Seleznev.


Aleshin V.,Physical and Technical Center . | Seleznev V.,Physical and Technical Center .
Journal of Konbin | Year: 2012

The paper describes an approach to the numerical analysis of response of nuclear power plant buildings including soil-structure interaction effects. A reinforced concrete structure of an NPP reactor building under operating and seismic loadings is considered. The simulated seismic load corresponds to a maximum designed earthquake of magnitude 7 (the peak ground surface acceleration is 0.12 g). The numerical analysis was performed by the finite element method in a 3D nonlinear statement using the FEM-programs ANSYS and LS-DYNA. Review of the numerical analysis results demonstrated that the presented technique can be successfully applied to seismic design of NPP structures.


Seleznev V.,Physical and Technical Center . | Komissarov A.,Physical and Technical Center . | Skiteva I.,Physical and Technical Center .
Journal of Konbin | Year: 2012

The article describes numerical method of physical gas flow parameters recovery at accidents investigation, which are conditioned by guillotine rupture of a pipe in gas trunkline and distribution pipeline systems. The information about full-scale measurements of time dependences of gas flow parameters at defined points inside pipelines system and at its boundaries is the base for recovery implementation at numerical investigation of accidents. Numerical recovery is carried out by defining and solving a special identification problem.


Seleznev V.E.,Physical and Technical Center | Aleshin V.V.,Physical and Technical Center | Kobyakov V.V.,Physical and Technical Center
Advances in Mechanical Engineering | Year: 2011

At present day, pipe mill engineers have to deal with challenging technological problems of heavy-wall and high-strength line pipe manufacturing. Numerical analysis of welded large-diameter pipe manufacturing stages is the most efficient way to solve these problems. Corresponding computational technologies and applied software were developed at Physical & Technical Center. Numerical structural analysis of steel plates at various stages of line pipe manufacturing is performed by the finite element method, accounting for geometric and material nonlinearities. The only thing to be done by the engineer in such analysis is to specify required input parameters. All the further process is software controlled. The discrepancy between the numerical analysis results and measured data in the overwhelming majority cases did not exceed 1. Copyright © 2011 Vladimir V. Aleshin et al.


Seleznev V.E.,Physical and Technical Center | Aleshin V.V.,Physical and Technical Center
Advances in Safety, Reliability and Risk Management - Proceedings of the European Safety and Reliability Conference, ESREL 2011 | Year: 2012

This paper presents a method for numerical evaluation of parameters of flammable liquid pool fires caused by storage tank or trunkline failures. As is well known, combustion of liquid fuel spilled on the terrain adjacent to the region of trunkline (or storage tank) rupture takes place as combustion of a stream of its vapor in the air. One of the main tasks of the considered approach practical application is to obtain significant upper estimate of potential or analysis of actual consequences of heat damage for facilities adjacent to pool fire site at the rupture region of trunklines transporting combustible fluids. At that it is necessary to take into consideration not only intensity, but also duration of fire. The method may be useful for specialists working in oil and gas, and chemical industries. It was successfully applied in fire safety analysis of gas and oil processing facilities. © 2012 Taylor & Francis Group.


Seleznev V.E.,Physical and Technical Center
Journal of Combustion | Year: 2010

This paper presents a method for numerical evaluation of parameters of flammable liquid pool fires caused by storage tank or trunkline failures. The method may be useful for specialists working in oil, gas, and chemical industries. It was successfully applied in fire safety analysis of Russian gas and oil processing facilities. Copyright 2010 Vadim E. Seleznev.

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