Moscow, Russia


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Mishin V.V.,Polytechnic University of Mozambique | Shishov I.A.,Polytechnic University of Mozambique | Glukhov P.A.,Polytechnic University of Mozambique | Zabrodin A.V.,JSC VNIINM | And 3 more authors.
Russian Metallurgy (Metally) | Year: 2016

A computer model is developed to describe the pressing of a beryllium lens using the Deform software package. This model takes into account the rheological properties of beryllium and the deforming tool. The state of stress of a workpiece is determined at various stages of pressing, and the probability of fracture of nanocrystalline beryllium is estimated using the normalized Cockcroft–Latham criterion. The temperature dependence of the limiting values of the fracture criterion is found and used to choose the pressing conditions that exclude fracture of lenses. © 2016, Pleiades Publishing, Ltd.

Skuratov V.A.,National Research Nuclear University MEPhI | Sohatsky A.S.,FLNR | O'Connell J.H.,Nelson Mandela Metropolitan University | Kornieieva K.,FLNR | And 6 more authors.
Physica Status Solidi (C) Current Topics in Solid State Physics | Year: 2016

Aim of this report is to compare the morphology of swift (167 and 220 MeV) Xe ion induced latent tracks in Y2Ti2O7 nanoparticles during post-irradiation heat treatment and after irradiation at different temperatures in pre-thinned TEM foils and TEM targets prepared from hundreds microns thick irradiated oxide dispersion strengthened (ODS) steel. No difference in track parameters was found in room temperature irradiated nanoparticles in pre-thinned and conventional samples. Microstructural data gathered from pre-thinned foils irradiated in the temperature range 350-650 °C or annealed at similar temperatures demonstrate that amorphous latent tracks interact with the surrounding matrix, changing the track and nanoparticle morphology, while such effect is not observed in conventional ODS material treated at the same conditions. (© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim). Copyright © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

Karasev Yu.V.,JSC VNIINM | Pantsyrny V.I.,JSC VNIINM | Polikarpova M.V.,JSC VNIINM | Lukianov P.A.,JSC VNIINM | And 4 more authors.
IEEE Transactions on Applied Superconductivity | Year: 2013

Commercial multifilamentary NbTi strands produced by the Russian Federation Domestic Agency for the ITER poloidal field (PF) coils PF1 and PF6 were characterized regarding Jc(B, T) by magnetization and transport measurements. The results of critical current measurements at magnetic fields in the wide range from 2 to 10 T and at temperatures from 3.5 to 7.5 K are presented. The experimental results were obtained at two laboratories; the two sets of data show a good match and demonstrate the high reproducibility of data. The current sharing temperature Tcs of the strands is between 5.9 and 6 K at 6.4 T at an operating current of 33 A. These results enable finding strand characteristic parameters for Jc}(B, T) fits and lead to a database, which is essential for the future analysis of experimental data for the PF conductor performance. © 2002-2011 IEEE.

Skuratov V.A.,FLNR | Sohatsky A.S.,FLNR | O'Connell J.H.,Nelson Mandela Metropolitan University | Kornieieva K.,FLNR | And 3 more authors.
Journal of Nuclear Materials | Year: 2014

Structural changes induced by 1.2 MeV/amu xenon, krypton and argon ion irradiation in Y2Ti2O7 pyrochlore nanoparticles in EP450 ODS steel have been studied using high resolution transmission electron microscopy. It was found that diameters of amorphous latent tracks formed by Kr and Xe ions are in the range 3-7 nm when electronic stopping powers vary from 10 to 24 keV/nm. The threshold for track formation is estimated to be between 7.4 keV/nm and 9.7 keV/nm. ©2014 Elsevier Ltd. All rights reserved.

Kolbasnikov N.G.,Saint Petersburg State Polytechnic University | Mishin V.V.,Saint Petersburg State Polytechnic University | Shishov I.A.,Saint Petersburg State Polytechnic University | Kistankin I.S.,Saint Petersburg State Polytechnic University | Zabrodin A.V.,JSC VNIINM
Russian Metallurgy (Metally) | Year: 2014

The critical values of the Cockcroft-Latham and Ayada criteria, which are embedded in the Deform-3D software package and can be used to describe the fracture of nanocrystalline beryllium at various stages of warm rolling, are determined. It is shown that excess over these critical values leads to the fracture of beryllium during both simulation and experimental rolling. Nondestructive conditions are developed for multipass warm rolling of beryllium with the minimum number of long-term intermediate high-temperature annealing. © 2014, Pleiades Publishing, Ltd.

Churyumov A.Y.,National University of Science and Technology "MISIS" | Khomutov M.G.,National University of Science and Technology "MISIS" | Solonin A.N.,National University of Science and Technology "MISIS" | Pozdniakov A.V.,National University of Science and Technology "MISIS" | And 2 more authors.
Materials and Design | Year: 2015

High-Cr ferritic-martensitic steels are important materials for use in nuclear reactors. This study describes a development activity for this category of steels involving the investigation of the hot deformation behaviour and microstructure evolution during hot deformation of 10CrMoWNb steel. Hot compression and tension tests were performed in the temperature range of 900-1350. °C by using a Gleeble 3800 thermomechanical simulator. The results indicate that the flow stress and ultimate tensile strength increase with a decrease of the deformation temperature and an increase of the strain rate. Based on the experimental true strain-true stress data, the modified Arrhenius-type constitutive model was established for a form of 10CrMoWNb ferritic-martensitic steel. The hot plasticity properties of the 10CrMoWNb steel increase with temperature up to 1275. °C due to dynamic recrystallisation processes in the austenite phase. The reduction of area decreases when the temperature is higher than 1300. °C and is zero at 1350. °C for all strain rates because of the liquid phase appearance in the structure of the steel. © 2015 Elsevier Ltd.

Chulkin D.A.,JSC VNIINM | Kuznetsov V.I.,JSC VNIINM | Krupkin A.V.,JSC VNIINM | Novikov V.V.,JSC VNIINM
LWR Fuel Performance Meeting, Top Fuel 2013 | Year: 2013

The article presents the calculation results of the FGR modeling by the START-3A code. The release model due to the microcracking of the large grains during the transient was developed During the modeling, the experimental data obtained in VNIINM was used. According to this data, the large grained (∼26 mkm) fuel has the cracking characteristics that differ from the cracking characteristics of the fuel with the standard grain size (11 mkm). In the large grained fuel, the cracks propagate through the grain bulk, and in the fuel with the standard grain sizes, they go between the grain boundaries. This can cause a significant fission gas release from the fuel with large grains in case if there is a big amount of fission gas products inside the grain. The model was tested on the experimental data of the IFA-676.1 irradiation in the Halden-reactor up to the burnups of 54 MWd/kgUO2. IFA-676.1 included the fuel rods with the pellets with grain sizes of 11 mkm and 26 mkm and instrumented with the temperature and pressure sensors. In the considered case, the fission gas release of the large-grained fuel was higher than that of the fuel with the standard grain. Before the power raise at approximately 15 MWd/kgUO2, the fission gas release from the large grained fuel was smaller, but after the power raise, the fission gas release from the large-grained fuel quickly went up and exceeded the fission gas release of the fuel with the standard grain size. The proposed model can qualitatively and quantitatively describe these experimental results - the fission gas products were released more intensively from the large grained fuel due to the microcracks that appear during the power rise. According to the calculations of the temperature and the fuel rod internal pressure of IFA-676.1, the experimental and calculation results are in the reasonable coincidence.

Kuznetsov V.I.,JSC VNIINM | Krupkin A.V.,JSC VNIINM | Novikov V.V.,JSC VNIINM
LWR Fuel Performance Meeting, Top Fuel 2013 | Year: 2013

The aim of the work was to determine fuel rod stress-strain state in transients with account of cracks development in fuel pellets. The calculations were performed in 2D and 3D states on the finite element package ANSYS. To present cracks development the cohesive zone model was used. Simulation was carried out under the following conditions: the real source pellet geometry; general contact pellets each other and the cladding; fuel pellet deformation with account of cracks generation.

Nikitina A.A.,JSC VNIINM | Ageev V.S.,JSC VNIINM | Chukanov A.P.,JSC VNIINM | Tsvelev V.V.,JSC VNIINM | And 2 more authors.
Journal of Nuclear Materials | Year: 2012

Present paper performs research results of structure and mechanical properties of the ODS steel on the base of steel EP450 (Fe-13Cr-2Mo-Nb-V-B-0, 12C) on all stages of producing: from powders to thin-walled tubes. Also, the results of research on method of sealing thin-walled tubes from steel EP450 ODS by pressurized resistance welding are shown. © 2011 Elsevier B.V. All rights reserved.

Krupkin A.V.,JSC VNIINM | Kuznetsov V.I.,JSC VNIINM | Novikov V.V.,JSC VNIINM | Sergienko I.R.,JSC VNIINM
International Congress on Advances in Nuclear Power Plants, ICAPP 2014 | Year: 2014

Transient operating conditions associated with the power increase are the most critical to the strength of the fuel cladding. Behavior of the fuel rod under transient conditions is characterized by intense interaction between fragmented pellets and the cladding that defines complicated stress-strain state of the cladding with a markable local increase of the hoop strain on the adjacent faces of the fuel pellets. Mechanical tests of the fuel cladding characteristics in the laboratory conditions are an integral part of a set of in-pile and out-of-pile experiments which are aimed on the study of certain factors (loading algorithm and rate, the concentration of corrosive fission products etc.) that affect the fuel cladding strength under transient operating conditions. Mandrel test is a mechanical test, which allows getting a good approximation of the stress-strained state of the cladding under transient conditions. In this type of loading stress field in the sample is determined by the results of finite element analysis (FEA). The report presents the results of FEA of mandrel test conducted on tubular El 10 alloy samples cut from the un-irradiated fuel cladding of the VVER-type reactor. A distinctive feature of the mandrel test is online registration of radial displacements of controlled area of the specimen during loading. Finite element analysis of mechanical tests were carried out in a 3D setting, using the ANSYS software.

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