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Огородникова, Ольга Вячеславовна

Организационные подразделения

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Институт лазерных и плазменных технологий

Стратегическая цель Института ЛаПлаз – стать ведущей научной школой и ядром развития инноваций по лазерным, плазменным, радиационным и ускорительным технологиям, с уникальными образовательными программами, востребованными на российском и мировом рынке образовательных услуг.

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Огородникова

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Ольга Вячеславовна

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Теперь показываю 1 - 10 из 11

Открытый доступ
HYDROGEN AND HELIUM RETENTION IN TUNGSTEN UNDER ION IRRADIATION
(НИЯУ МИФИ, 2017) Gasparyan, Yu.; Zibrov, M.; Efimov, V.; Ryabtsev, S.; Ogorodnikova, O.; Pisarev, A.; Писарев, Александр Александрович; Гаспарян, Юрий Микаэлович; Огородникова, Ольга Вячеславовна
Interaction of helium and hydrogen ions with tungsten is intensively investigated during last decades in relation to construction of fusion reactor. Tungsten has the high melting temperature and the energy threshold for sputtering and, therefore, is considered as plasma facing material (PFM) in fusion devices in the area of largest heat loads and small energies of ions (divertor area). In particular, tungsten will be used in the international experimental reactor ITER, which is now under construction.
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CORRELATION OF DEUTERIUM RETENTION WITH CRYSTALLINE STRUCTURE IN DENSE AND DISORDERED TUNGSTEN COATINGS
(НИЯУ МИФИ, 2017) Ogorodnikova, O. V.; Ruset, C.; Dellasega, D.; Pezzoli, A.; Passoni, M.; Sugiyama, K.; Gasparyan, Yu.; Efimov, V.; Ефимов, Виталий Сергеевич; Гаспарян, Юрий Микаэлович; Огородникова, Ольга Вячеславовна
Dense nano-structured tungsten (W) coatings are used as plasma-facing materials in current tokamaks and thick coatings are suggested to be used also for the future fusion devices, ITER and DEMO. In this study, deuterium (D) retention in various W coatings was investigated to understand dependences of the D retention on the crystalline structure of each W coating and on the substrate material.
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Migration, trapping and release of deuterium from tungsten in the presence of high density of defects: theory and experiment
(НИЯУ МИФИ, 2015) Ogorodnikova, O. V.; Огородникова, Ольга Вячеславовна
The most common experimental methods to study hydrogen (H) in a metal are nuclear reaction method (NRA) for depth profile measurements, thermal desorption spectroscopy (TDS) and permeation experiments. Rate equations are used to model experimental data. The diffusivity, solubility, reflection coefficient, surface barrier, binding energies of H with different types of defects and density of defects are input parameters for rate equation model. These parameters can be derived from the first-principle (DFT) calculations, effectivemedium theory (EMT), molecular dynamics (MD) and TRIM calculations. Incorporation of binding energies of deuterium (D) with a vacancy and a dislocation recently calculated by DFT [1,2] and penetration probability and ion range calculated by MD and TRIM [3] in the rate equation model allows us to validate different predictions against experimental data, for the first time. A comparison of the first-principle calculations and calculations by other theoretical models with experimental values can clarify the physics underling the hydrogenmetal interaction and can provide an answer on several important questions, namely, (i) which type of trap corresponds to certain D binding energy, (ii) which is a range of validity of MD and TRIM models and (iii) which process is rate-limited in respect to the D uptake and release in a material.
Только метаданные
Deuterium and helium retention in W with and without He-induced W ‘fuzz’ exposed to pulsed high-temperature deuterium plasma
(2019) Tokitani, M.; Ogorodnikova, O. V.; Klimov, K. S.; Poskakalov, A. G.; Kaziev, A. V.; Kharkov, M. M.; Efimov, V. S.; Gasparyan, Y. M.; Volkov, N. V.; Alimov, V. K.; Огородникова, Ольга Вячеславовна; Климов, Николай Сергеевич; Казиев, Андрей Викторович; Харьков, Максим Михайлович; Ефимов, Виталий Сергеевич; Гаспарян, Юрий Микаэлович
© 2018 Elsevier B.V. In the present work, helium (He) was incorporated into tungsten (W) samples by inductively coupled plasma (ICP) source above the threshold of He-induced W ‘fuzz’ formation on W surface. Then, W samples with and without nano-structured W ‘fuzz’ were exposed to pulsed heat loads using deuterium (D) plasma in quasi-stationary high-current plasma gun QSPA-T. The pulse duration was 1 ms and number of pulses was varied from one to thirty to simulate ITER transient events with surface heat load parameters relevant to edge-localized-mode (ELM) impacts. The irradiation was performed below and above the W melting threshold. The D and He retention in each irradiated sample was measured by a method of thermal desorption spectroscopy. We examined the impact of (i) ELMs-like events and (ii) formation of He-induced nano-structured ‘fuzz’ on the D retention in W. We found that the D retention was the highest for samples irradiated by plasma gun above the melting threshold after thirty pulses. Moreover, the D retention after 10 pulses of deuterium plasma gun exposure was higher than that after stationary low-energy plasma exposure at sample temperature of either 600 or 700 K indicating the dominate influence of ELM's-like events on the D retention compared to normal operation regime. The D retention in W samples with the presence of He-induced W ‘fuzz’ was slightly smaller than without that after one pulse of plasma gun exposure with heat load below the W melting temperature. The W ‘fuzz’ was not disappear in this loading conditions, only the length and thickness of nano-structured W fibres were reduced by factors of ∼4 and ∼2, respectively. The He concentration in W with W ‘fuzz’ was decreased by a factor of about 3 after one pulse of plasma gun exposure. The results obtained give possibility to assess the particle retention in divertor areas subjected to high thermal loads at different operation regimes.
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DEUTERIUM RE-EMISSION AND THERMAL DESORPTION FROM IRON AND EUROFER
(НИЯУ МИФИ, 2017) Ryabtsev, S. A.; Gasparyan, Yu. M.; Ogorodnikova, O. V.; Harutyunyan, Z. R.; Pisarev, A. A.; Арутюнян, Зорий Робертович; Огородникова, Ольга Вячеславовна; Писарев, Александр Александрович; Гаспарян, Юрий Микаэлович
Reduced-activation ferritic-marthensitic (RAFM) steels, such as Eurofer, are considered as candidates for structural materials in fusion reactors due to the high thermal conductivity, the low thermal expansion coefficient and good resistance to radiation swelling. There are also some concepts of fusion reactors, where RAFM steels also considered as material for plasma-facing components. In this regard, the key aspects of hydrogen (H) isotopes interaction with RAFM steels, such as tritium (T) retention and migration in these materials are particularly important as a point of safety concern.
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Verification of the theory of primary radiation damage by comparison with experimental data
(2019) Majerle, M.; Gann, V. V.; Cizek, J.; Hruska, P.; Ogorodnikova, O. V.; Огородникова, Ольга Вячеславовна
© 2019 Elsevier B.V.Understanding of radiation damage in a solid is important for development of advanced material technologies, namely, for space application, electron microscopy, semiconductor processing, fission and nuclear fusion. Space materials must withstand exposure to high-energy protons. Construction materials of future thermonuclear reactors must withstand exposure to high-energy neutrons. Many properties of materials including mechanical properties are governed by the presence and behavior of lattice defects. Hence, the study of the radiation-induced defects is an important task combining two fields: radiation physics and solid state physics. The paper presents new knowledge on primary defect formation in the main materials for advanced fission and nuclear fusion reactors, bcc tungsten (W) and bcc iron (Fe). The objective of this work is to compare the new experimental data of neutron- and proton-induced defects in W and Fe using well-established method of positron-annihilation lifetime-spectroscopy (PALS) in combination with the literature data with two models of radiation damage, the classical Norgett-Robinson-Torrens (NRT-dpa) model and recently developed athermal recombination corrected (arc-dpa) model. It is shown that experimental data for neutron- and proton-irradiated Fe are better described by arc-dpa model than NRT-dpa model. Whereas experimental data for neutron- and proton-irradiated W are between the NRT-dpa and arc-dpa predictions. The obtained results shed new light on the formation of the primary radiation defects in materials and indicate the need for further development of the theory of radiation damage in a solid.
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Recombination coefficient of hydrogen on tungsten surface
(2019) Ogorodnikova, O. V.; Огородникова, Ольга Вячеславовна
© 2019 Elsevier B.V. The recombination coefficient is an important parameter for modelling hydrogen-metal interaction. It is responsible for hydrogen desorption from the surface of the metal and, therefore, significantly affects the hydrogen penetration into the metal, accumulation in and permeation through the metal. In the present work, the recombination coefficient of hydrogen (H) on tungsten (W) surface is examined. It is shown that the recombination coefficient of H on a clean W surface is extremely high which indicates the rapid desorption of the hydrogen molecule from the surface. Simulation using a high recombination coefficient well describes a wide range of experimental data of gas and ions interaction of hydrogen isotopes with tungsten. Proof of incorrectness of the Anderl's recombination coefficient is presented by comparing it with both theory and experiment.
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Surface Structure Modification and Deuterium Retention in Tungsten under Pulsed Plasma Loads
(2019) Poskakalov, A. G.; Klimov, N. S.; Gasparyan, Y. M.; Ogorodnikova, O. V.; Efimov, V. S.; Климов, Николай Сергеевич; Гаспарян, Юрий Микаэлович; Огородникова, Ольга Вячеславовна; Ефимов, Виталий Сергеевич
© 2019, Pleiades Publishing, Ltd.Modification of the surface layer and deuterium accumulation in tungsten targets under plasma irradiation in a quasi-stationary plasma accelerator with an intrinsic magnetic field QSPA-T, which reproduces the conditions (plasma thermal load of 0.2-5 MJ/m2, pulse duration of 0.1-1.2 ms) typical of ELM events in ITER, are studied. Using a scanning electron microscope, structure modifications at the surface and in the bulk after deuterium plasma irradiation are analyzed. The observed changes in the near-surface layer are compared with the calculated data on the change in the internal structure of tungsten under intense thermal action obtained as a result of the numerical solution of the heat conduction problem. The total deuterium retention in the samples was measured using thermal desorption spectroscopy, and it was in the range of (3-4) × 1016 particles/cm2 for the samples melted during plasma exposure. These numbers exceed by an order of magnitude the values obtained for samples without traces of melting.
Только метаданные
Annealing of radiation-induced defects in tungsten: Positron annihilation spectroscopy study
(2019) Terentyev, D.; Funtikov, Y. V.; Stolbunov, V. S.; Ogorodnikova, O. V.; Dubov, L. Y.; Stepanov, S. V.; Shtotsky, Y. V.; Efimov, V.; Gutorov, K.; Огородникова, Ольга Вячеславовна; Дубов, Леонид Юрьевич; Степанов, Сергей Всеволодович; Штоцкий, Юрий Владимирович; Ефимов, Виталий Сергеевич; Гуторов, Константин Михайлович
© 2019 Elsevier B.V. Positron annihilation lifetime spectroscopy (PALS) was applied to study the annealing of radiation-induced defects in polycrystalline tungsten (W) irradiated with 21.6 MeV protons at 100 °C up to a fluence of 5 × 10 15 p/cm 2 . Three components were observed in the measured spectra: short-lifetime of 100–120 ps (positron annihilation in the defect-free W lattice), medium-lifetime of ∼190–330 ps (annihilation at mono-vacancies and small vacancy cluster containing ∼ 2–4 vacancies) and long-lifetime of ∼500 ps (annihilation in large vacancy clusters containing more than 10 vacancies). The irradiation of W with protons at 100 °C, primary, led to the formation of mono-vacancies, self-interstitial defects were created as well but migrated towards sinks during the irradiation. Onset of vacancy diffusion in W starts already at 200 °C before defect recovery stage III. After annealing at ∼400 °C, a sharp drop in the intensity of the positron medium-life component together with a simultaneous increase in positron lifetime from ∼220 to ∼280 ps is observed, and a long-life component appears. This indicates migration and annealing of vacancies and their agglomeration in large vacancy clusters. After annealing at 500–700C, the intensity of long-life component increases indicating the growth of large vacancy clusters but at 900 °C they anneal completely as the mean lifetime recovers nearly to the value measured in the un-irradiated material.
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НАКОПЛЕНИЕ ДЕЙТЕРИЯ В ВОЛЬФРАМЕ ПРИ МОЩНЫХ ИМПУЛЬСНЫХ ПЛАЗМЕННЫХ НАГРУЗКАХ
(НИЯУ МИФИ, 2019) ПОСКАКАЛОВ, А. Г.; КЛИМОВ, Н. С.; ГАСПАРЯН, Ю. М.; ОГОРОДНИКОВА, О. В.; ЕФИМОВ, В. С.; ЗИБРОВ, М. С.; Огородникова, Ольга Вячеславовна; Гаспарян, Юрий Микаэлович; Климов, Николай Сергеевич; Ефимов, Виталий Сергеевич
В Международном термоядерном реакторе ИТЭР в качестве обращенных к плазме материалов будут использоваться вольфрам (W) и бериллий (Be). Из вольфрама будет изготовлено защитное покрытие диверторных пластин, а из бериллия — поверхность первой стенки. Тепловые нагрузки на пластины дивертора в токамаке масштаба ИТЭР в стационарной стадии DT-разряда будут достигать ~10 МВт/м2, приводя к повышению температуры пластин в среднем до 1400 К; в срывах и ЭЛМах импульсные кратковременные нагрузки на диверторные пластины будут достигать величины 0,6 – 3,5 ГВт/м2, что будет вызывать периодическое повышение температуры материала до температуры, сопоставимой с температурой плавления материала.