Effects of irradiation of stainless steel and TiMoN coatings on stainless with lowenergy Alpha-particles, Krypton and Xenon ions

One of the directions for development of new structural materials for nuclear installations is deposition of protective coatings with high stability of physical and mechanical properties to ionizing irradiation on the existing structural materials. In particular, this applies to the nuclear reactors of generation IV, among which are considered as promising reactors with liquid metal and gas coolant..

Effects of irradiation of stainless steel and TiMoN coatings on stainless with lowenergy Alpha-particles, Krypton and Xenon ions

One of the directions for development of new structural materials for nuclear installations is deposition of protective coatings with high stability of physical and mechanical properties to ionizing irradiation on the existing structural materials. In particular, this applies to the nuclear reactors of generation IV, among which are considered as promising reactors with liquid metal and gas coolant..

Impact of pulsed plasma beam on the thermal erosion and the surface structure of graphite

Among materials prospective as plasmaface materials for first wall of fusion reactor a priority is given to the materials with low atomic number, high threshold for physical sputtering, high thermal conductivity, low chemical activity to hydrogen, high thermal resistance and melting point. According to modern point of view, preferred plasma-face materials for tokamaks and future Generation IV reactors should be based on the carbon, beryllium and tungsten. Tungsten is one of the most promising materials for protection of tokamaks diverter plates

Impact of pulsed plasma beam on the thermal erosion and the surface structure of graphite

Among materials prospective as plasmaface materials for first wall of fusion reactor a priority is given to the materials with low atomic number, high threshold for physical sputtering, high thermal conductivity, low chemical activity to hydrogen, high thermal resistance and melting point. According to modern point of view, preferred plasma-face materials for tokamaks and future Generation IV reactors should be based on the carbon, beryllium and tungsten. Tungsten is one of the most promising materials for protection of tokamaks diverter plates

Radiation thermal processes in Cr13Mo2NbVB steel - the material of the fuel assembly shell in reactor BN-350 under mechanical tests

Regularities of changes of structural-phase state and mechanical properties of steel 13Mo2NbVB - the material of the fuel assembly shell in reactor BN-350 after various mechanical tests at 350°C are experimentally studied. The formation of microprecipitations FeMo, enriched or depleted with molybdenum was found in the short-time mechanical tests, which is the cause of thermal hardening of irradiated Cr13Mo2NbVB steel and its destruction by the ductile-brittle mechanism. On the basis of long-time creep tests it was shown that the material of the spent fuel assembly shell has sufficient resource for long-time storage in the temperature and force conditions simulating long-time storage of spent nuclear fuel

Features of radiation damage of Ni-Ti alloy under exposure to heavy ions of gaseous elements

The consistent patterns of changes in structural and phase state, hardening and temperature ranges of martensitic transformations in Ni-Ti alloy with the shape memory effect after implantation of heavy ions 16O3+, 40Ar8+ and 84Kr15+ under comparable parameters have been experimentally studied. It is found that under the impact of 84Kr15+ ions, a two-layer surface structure with radiation-hardened second layer is formed, radiation-stimulated phase transformation B19'>B2 occurs in the near-surface layer and out-range area, and the martensitic transformation temperature increases toward higher values after implantation of 40Ar8+ and 84Kr15+ ions

Radiation thermal processes in Cr13Mo2NbVB steel - the material of the fuel assembly shell in reactor BN-350 under mechanical tests

Regularities of changes of structural-phase state and mechanical properties of steel 13Mo2NbVB - the material of the fuel assembly shell in reactor BN-350 after various mechanical tests at 350°C are experimentally studied. The formation of microprecipitations FeMo, enriched or depleted with molybdenum was found in the short-time mechanical tests, which is the cause of thermal hardening of irradiated Cr13Mo2NbVB steel and its destruction by the ductile-brittle mechanism. On the basis of long-time creep tests it was shown that the material of the spent fuel assembly shell has sufficient resource for long-time storage in the temperature and force conditions simulating long-time storage of spent nuclear fuel

Steel surface TiCrN, TiMoNcoatings structural phase state change features after low-energy alpha particles irradiation

The low-energy alpha particles irradiation impact on structural phase composition and 321S31 steel surface TiCrN and TiMoN coatings morphology have been summarized. The samples irradiation has been carried out in the DTs-60 (the Dubna cyclotron) heavy-ion accelerator by the{4}He{+2} low-energy ions (40 keV) into a 1.0•10{17} ion/cm{2} fluence. It has been established thatthe 321S31 steel alpha particles implantation having energy of 40 keV results in the austenite initial γ-structurepartial transfer, stimulated by the irradiation, to the martensiteα-structure. The low-energy alpha particles irradiation within the fluencies range from 10{16} to 10{17} ion/cm{2} for the TiCrN and TiMoN coatings formed by the ionic bombardment condensation method doesn't result in the phase transfers with a coating crystal lattice type change

Study of irradiation temperature effect on change of structural, optical, and strength properties of BeO ceramics when irradiated with Ar8+ and Xe22 heavy ions

This paper presents the results of the study of the effect of irradiation temperature on structural and optical distortions and deformations, as well as the strength properties of BeO ceramics as a result of irradiation with Ar8+ and Xe22+ ions at a radiation dose of 5 × 1013 cm-2. The choice of radiation dose is due to the effect of overlapping defective areas arising along the trajectories of ions in ceramics, which makes it possible to model radiation damage caused by the effect of accumulation as a result of cascade collisions and overlapping damaged areas. The temperature range of 300–1000 K was chosen to simulate different operating conditions, as well as the possibility of simulating partial annealing of defects during irradiation at high temperatures. During the research, it was established that high-temperature radiation reduces influence of size of electronic and nuclear power losses of ions of Ar8+ and Xe22+ with energy of 70 MeV and 231 MeV, respectively, on extent of radiation damage of ceramics of BeO. Irradiation at a temperature of 1000 K results in an equal 14% change in dislocation density for these particles, a comparable decrease in the yield intensity of optically stimulated luminescence by 5% and 15%, as well as microhardness by 25% and 30%, respectively. © 2021, The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.This research was funded by the Science Committee of the Ministry of Education and Science of the Republic of Kazakhstan (No. AP08855828)

Stent-assisted coiling of acute ruptured cerebral aneurysms

The necessity of quick surgical treatment of acute ruptured cerebral aneurysms was demonstrated in large studies by the ISAT and ISUIA, which also proved the advantage of the endovascular method over the surgical one. Ballonassistence is widely used in treatment of aneurysms with wide neck and unfavorable vascular anatomy, but the radicality of the treatment is insufficient. The aim of this study was to demonstrate the efficacy and safety of stent-assisted embolization of «acute» cerebral aneurysms. Material and methods. A retrospective analysis of the treatment of 234 patients with «acute» cerebral aneurysms was carried out. Results. Only coils were used in 40.6 % of cases (n = 95), balloon-assistance, in 40.2 % of cases (n = 94), and stent-assistance, in 19.2 % of cases (n = 45). There were 11.5 % (n = 27) clinically significant complications. Total aneurysm occlusion (Raymond-Roy I) was achieved in 187 cases (79.9 %); the radicality at the control examination was 67.1 % (157 patients). Discussion. The radicality of the treatment with stents was slightly higher then with balloons and coils at the end of operation (84.4 %, n = 38 and 78.8 %, n = 149, p > 0.05), but it was significantly higher at the control examination (80.0 %, n = 36 and 60.8 %, n = 115, respectively, p <0.05). Also, we had no statistically significant difference of the complication rate in the «stent» and «no stent» groups; therefore, the clinical outcomes of endovascular treatment of cerebral aneurysms did not depend on the choice of treatment method. Conclusions. Intracranial stents allow achieving good results of the embolization of complex aneurysms in the acute period of intracranial hemorrhage without increasing the risk of surgical treatment