2021, Harutyunyan, Z., Gasparyan, Yu., Pisarev, A., Litnovsky, A., Klein, F., Linsmeier, Ch., Писарев, Александр Александрович, Гаспарян, Юрий Микаэлович, Арутюнян, Зорий Робертович

During operation of the future fusion power plant, the plasma-facing components (PFC) will be exposed to intense fluxes of particles of deuterium, tritium, helium, as well as neutrons arising in the process of the D–T fusion reaction. In this regard, one of the important challenges is to minimize the accumulation of radioactive tritium in the PFC [1, 2], as well as to study the effect on the accumulation of helium impurities in the plasma.

2022, Kanashenko, S., Harutyunyan, Z., Ogorodnikova, O. V., Gasparyan, Y., Efimov, V., Sorokin, I., Sergeev, N., Арутюнян, Зорий Робертович, Огородникова, Ольга Вячеславовна, Гаспарян, Юрий Микаэлович, Ефимов, Виталий Сергеевич, Сорокин, Иван Александрович, Сергеев, Никита Сергеевич

© 2022 Elsevier B.V.Using a beam-plasma discharge device operating on helium (He), tungsten with the fuzz on the surface (Wf) has been formed by irradiating polycrystalline tungsten (W) samples with He ions with an energy of ∼150 eV and the fluence of ∼6 × 1024 He/m2 at the temperature of 1273 K. The deuterium (D) retention in Wf annealed at different temperatures was studied by thermal desorption spectroscopy (TDS). Before and after annealing at temperatures of 1000,1200,1400 and 1600 K, Wf was irradiated at room temperature by 2 keV D3+(667 eV/D) ions with the fluence of 1021 D/m2, then in-situ TDS was performed after each irradiation. Annealing W above 1200 K clearly changes the retention mechanism of D: the TDS spectrum consisting of multiple peaks changes to an almost single-peak spectrum. Annealing at 1600 K leads to surface smoothing and the decrease of the D retention by a factor of two compared to the annealing at 1000 K. This can be explained by an increase of the reflection coefficient for the flat W surface. However, the D retention in Wf is significantly higher compared to that in W without He plasma exposure even after annealing at 1600 K, because there are still He bubbles in Wf that effectively trap D

2019, Kanashenko, S., Ivanov, Y., Ryabtsev, S., Gasparyan, Y., Efimov, V., Harutyunyan, Z., Aksenova, A., Poskakalov, A., Pisarev, A., Гаспарян, Юрий Микаэлович, Ефимов, Виталий Сергеевич, Арутюнян, Зорий Робертович, Аксенова, Александра Сергеевна, Писарев, Александр Александрович

© 2019Helium (He) retention in re-crystallized tungsten (W) irradiated with He+ ions at elevated temperatures (700–1200 K) and fluences in the range of 1020–1022 He/m2 was investigated by means of thermal desorption spectroscopy (TDS). Corresponding surface modifications were analyzed by scanning electron microscopy. Blisters were observed after irradiation at 700 and 1000 K, while the increase of the irradiation temperature up to 1200 K led to development of a complex sponge-like structure on the W surface. Significant surface transformations correlated with appearance of low temperature peaks in TDS spectra below the irradiation temperature. Possible mechanisms and explanations are discussed.

2025, Umerenkova, A., Harutyunyan, Z., Ogorodnikova, O., Gasparyan, Y., Ostojic, N., Efimov, V., Умеренкова, Анастасия Сергеевна, Арутюнян, Зорий Робертович, Огородникова, Ольга Вячеславовна, Гаспарян, Юрий Микаэлович, Остойич, Никола, Ефимов, Виталий Сергеевич

2021, Kanashenko, S., Harutyunyan, Z., Gasparyan, Y., Ryabtsev, S., Efimov, V., Ogorodnikova, O., Pisarev, A., Арутюнян, Зорий Робертович, Гаспарян, Юрий Микаэлович, Ефимов, Виталий Сергеевич, Огородникова, Ольга Вячеславовна, Писарев, Александр Александрович

© 2021The effect of He-induced defects in tungsten on the efficiency of trapping of deuterium ions in the subsurface layer was studied using thermal desorption spectroscopy (TDS). The W sample was pre-irradiated with 3 keV helium ions at room temperature and various fluences in the range of 1019 – 5 × 1021 He/m2. Then, it was exposed to a probe fluence of 1019 D/m2 of 2 keV D3+ (670 eV/D) ions, and in-situ TDS was performed. The de-trapping energy for D atoms increased with the increase of the He pre-irradiation fluence. On the other hand, a strong decrease in the D retention was observed if the He fluence increased above 1021 He/m2. At the highest He fluence of 5 × 1021 He/m2 deuterium trapping was possible only after partial release of He atoms. By comparison of experimental TDS spectra with modeling, the de-trapping energies of D atoms from various defects were estimated.

2022, Litnovsky, A., Klein, F., Coenen, J. W., Linsmeier, C., Harutyunyan, Z., Gasparyan, Y., Efimov, V., Pisarev, A., Арутюнян, Зорий Робертович, Гаспарян, Юрий Микаэлович, Ефимов, Виталий Сергеевич, Писарев, Александр Александрович

© 2022Deuterium (D) retention in tungsten-chromium-yttrium (W–Cr–Y) alloy depending on the irradiation fluence of 1019–5 × 1021 D/m2 at various sample temperatures in the range of 300–900 K was investigated using in-situ thermal desorption spectroscopy (TDS). The irradiation was carried out using 2 keV D3+ ions (670eV/D). An increased D retention compared to that of pure polycrystalline W and additional high-temperature peaks were observed in TDS. The de-trapping energy of 2.21 ± 0.05 eV for these traps was determined by the Kissinger method using the series of experiment with different heating rates. The total D retention dropped down at elevated irradiation temperatures and was rather small at 900 K, but has a local maximum at about 700 K.

2023, Harutyunyan, Z., Ogorodnikova, O. V., Gasparyan, Y. u., Umerenkova, A., Wang, Y., Арутюнян, Зорий Робертович, Огородникова, Ольга Вячеславовна, Гаспарян, Юрий Микаэлович, Умеренкова, Анастасия Сергеевна

2022, Ogorodnikova, O. V., Harutyunyan, Z., Gasparyan, Y., Efimov, V., Огородникова, Ольга Вячеславовна, Арутюнян, Зорий Робертович, Гаспарян, Юрий Микаэлович, Ефимов, Виталий Сергеевич

© 2022The helium (He) retention and the influence of He-induced defects on the deuterium (D) retention and migration in Eurofer97 were investigated by in-situ and ex-situ thermal desorption spectroscopy technique. Samples were pre-irradiated with 3 keV He ions in the fluence range of 1019–1022 He/m2, then irradiation with 2 keV D3+ ions (667 eV/D) with a fluence of 1021 D/m2 was performed. Experiments were carried out at the sample temperature of 300 K. It was shown that the D retention in Eurofer97 increases and decreases with pre-irradiation with He fluences below and above 1021 He/m2, respectively. However, in all cases of He pre-irradiation, the D retention is higher than that in Eurofer97 without He pre-irradiation. The effect of the reduction of the D retention at He fluences above 1021 He/m2 can be connected with either the formation of open porosity due to interconnected bubbles or the strain field induced by high pressurized He bubbles that preventing D penetration into the bulk of a metal. Both effects reduce the D diffusion towards the bulk of a metal and, therefore, lead to a decrease in the D retention. Our data of in-situ and ex-situ experiments revealed that HemVn complexes in the temperature range of 600–800 K are unstable and transformed in stable HemVn complexes in the temperature range of 900–1100 K after air exposure. Due to a formation of oxide layer during a contact with the atmosphere, ex-situ TDS of D leads to a shift of the D release temperature in the high-temperature range compared to in-situ TDS in both cases with and without He pre-irradiation. Finally, the presence of He in a metal lattice will have the dominant influence on the D retention in the future fusion devices together with neutron irradiation and high temperature gradient. In the case of He saturation, the similar D retention was measured in different bcc metals and their alloys.

2023, Harutyunyan, Z., Gasparyan, Y., Efimov, V., Krat, S., Umerenkova, A., Арутюнян, Зорий Робертович, Гаспарян, Юрий Микаэлович, Ефимов, Виталий Сергеевич, Крат, Степан Андреевич, Умеренкова, Анастасия Сергеевна

Helium (He) isotope exchange in tungsten (W) during sequential irradiation by 3 keV 4He and 3He ions at room (RT) and elevated temperatures (700-1200 K) was investigated. The total He fluence was in the range of 5 × 1021–1.8 × 1022 He/m2 to provide a saturation of the surface layer. The amount of He retained in W after irradiation was measured using in-situ (up to 1500 K) and ex-situ (up to 2500 K) thermal desorption spectroscopy (TDS). Air exposure influenced TDS spectra, but clear were no noticeable differences between 3He and 4He TDS spectra after single irradiation. Subsequent irradiation with different He isotopes demonstrated a very efficient isotope exchange already at room temperature. The substitution of He atoms goes even faster with increasing irradiation temperature. Mechanisms of observed processes are discussed on the base of a simple model. © 2022

2024, Wang, Y., Harutyunyan, Z., Gasparyan, Y., Ogorodnikova, O., Sinelnikov, D., Efimov, N., Umerenkova, A., Grishaev, M., Арутюнян, Зорий Робертович, Гаспарян, Юрий Микаэлович, Огородникова, Ольга Вячеславовна, Синельников, Дмитрий Николаевич, Ефимов, Никита Евгеньевич, Умеренкова, Анастасия Сергеевна, Гришаев, Максим Валерьевич