The paper presents the results of thermal shock tests of non-irradiated mock-ups of WWER-1000 reactor absorber elements made of 42KhNM alloy with dysprosium hafnate pellets. Experiments of cyclic thermal tests and corrosion resistance tests in a steam-water environment at temperatures up to 1300°C of individual dysprosium hafnate pellets were conducted. The tests and studies were conducted taking into account the design service life of the absorber elements of WWER-1000 protection control systems during 20 years, the average value of reactor shutdown-startup cycles from 15 to 40, and design basis accident conditions for tolerant fuel.

The paper presents the results of numerical testing of the developed algorithm for optimization of the sequence of dismantling of graphite stack blocks. The article evaluates the reduction of financial expenses for radioactive graphite removal during decommissioning of RBMK-1000 reactor units on the example of Leningrad NPP. This effect is achieved by reducing the required number of containers for the 2nd class of radioactive waste to be removed.

Decommissioning of nuclear power plants and deactivation of reactor primary loop from radioactive surface deposits during scheduled repairs is one of the urgent problems of the nuclear industry. Widely used radiochemical methods of deactivation lead to an increase in the secondary radioactive waste volume. Therefore, to solve effectively the deactivation problem, we are developing the “dry” ion-plasma technology based on the ion and thermal sputtering of radioactive surface deposits in an inert gas and eliminating the formation of liquid radioactive waste. This article presents the results of the experimental test of the ion-plasma technology operability at laboratory conditions using the metal samples of reactor stainless steel, brass alloys, copper and aluminum. The ranges of technology operating parameters were experimentally determined.

In this work, the nanostructure of oxide dispersion-strengthened steel 13.5Cr–Fe₃Y ODS, obtained by mechanical alloying of oxidized matrix steel powder and Fe₃Y intermetallic powder. In addition to the initial state, the effect of thermal aging on the nanostructure of this steel at 650°C for 500 and 1000 h was investigated. In the studied states of 13.5Cr–Fe₃Y ODS steel, transmission electron microscopy (TEM) has detected nanoscale oxides (~10–12 nm) with a number density of ~4–7 ×10²¹ m⁻³, pores (~3.0–3.6 nm and ~2–4 × 10²² m⁻³), as well as the dislocations ~2 × 10¹⁴ m⁻². According to the energy-dispersive X-ray spectroscopy analysis, oxide particles are mainly enriched in Y and O, and the detected pores contain up to 3 at. % Ar. Atom probe tomography (APT) revealed the presence of clusters (~3–5 nm and ~8–30 × 10²² m⁻³). The detected clusters also contain Ar within 0.1 at. %. Comparison of the data on the initial state and states after thermal aging revealed an increase in the number density of oxides and a decrease in their size with an increase in the thermal aging time, while the volume of the oxide phase at 1000 h remains the same relative to the initial state in the error limits. Comparison of APT data showed an increase in the volume of clusters during aging up to 500 h and a decrease in the volume at 1000 h. An increase in the number of oxides during thermal aging up to 1000 h correlates with a decrease in the volume of clusters in the same state. There is a significant (~2 times) decrease in pore volume during thermal aging. The density of dislocations increases to ~5 × 10¹⁴ m⁻² when reaching 1000 h of aging.

The results of a comprehensive multiscale study of the structure and distribution of boron in the fracture zone of high temperature Ni-based superalloy EP741NP, produced by PM HIP technology using rapidly quenched PREP powder, after high-temperature tensile test are presented. A detailed study of the macro-, meso-, microstructures and distribution of boron in the fracture zone was carried out using the direct nuclear-physical method of track autoradiography on boron in cooperation with metallographic (LM), (SEM), (EDX) and OIM methods. The effect of dynamic strain aging (DSA) with the engagement of boron at the fracture stage was revealed. It consists in intensive boron migration in the plastic deformation zone of the neck with an abnormally high effective diffusion coefficient and the formation of large allotriomorphic precipitates of the boride phase M ₃ B ₂ on the mesoscale shear loop and mesoscale shear bands of the Portevin-Le Chatelier (PLC) type in the loop crown, localized around the opening mesoscale crack in the area of localized deformation of the neck. The revealed effect of DSA with the engagement of boron is similar to the effect of DSA with the engagement of carbon and the formation of PLC bands decorated with dispersed carbides in nickel-based superalloys and austenitic stainless steels at the stage of work hardening.

A method for measuring the load characteristics of axial and radial bearings has been developed and tested. The load characteristics of bearings with various geometries based on modern superconducting tapes have been examined. The dependences of the vertical and lateral forces on the corresponding displacement have been obtained and analyzed, and the stabilities of the bearings have been compared. The method is appropriate for measurements in the zero-field cooling (ZFC) regime and in the field cooling (FC) regime, i.e., in a nonzero field at the boiling temperature of liquid nitrogen.

Based on the theory of the interaction of electrons with matter (Bethe, Heitler, Bloch) during their multiple scattering (Goudsmit, Saunderson), analytical expressions were obtained for the electron transmission coefficient and the energy yield of bremsstrahlung. These expressions depend on the material and thickness of the target and the initial kinetic energy of the electron. An analytical expression for the electron range was also obtained with insignificant simplifications, using the Lambert-function.

When modeling neutron dd-generators, it is necessary to take into account the deuteron energy drop in the simulation step, which leads to a rapid drop in the inelastic dd-interaction cross sections. An algorithm for optimal choice of the modeling step for inelastic dd-interaction is proposed, taking into account the decrease of the deuteron energy per step. Using the Lindhard law (at low energies, the energy losses of a charged particle are proportional to its velocity), an algorithm for correcting deuteron energy loss per step has been developed. Using these two algorithms can speed up the modeling of a neutron dd-generator target by an order of magnitude.

A study of the spectrometric characteristics of a 50 × 50 × 700 mm sample of a Russian-made plastic scintillator based on polystyrene was carried out. An energy resolution value (13.3 ± 0.5)%/MeV in units of FWHM was obtained, and uniformity of light collection was demonstrated. It is shown that the Russian plastic scintillator is not inferior in its characteristics to foreign analogues.

The intrinsic and mutual inductivities of the central inductor, coils PF1–PF6 of the MEPhIST-0 electromagnetic tokamak system and the tokamak discharge chamber in the frequency range from 50 to 15 000 Hz are determined. It has been found that in the low frequency range up to ~200 Hz, to determine the mutual effects of the most strongly coupled coils, it is possible to represent the discharge chamber as one short-circuited coil inductively connected to the coils of a poloidal system.

The paper describes the development and testing of the power supply system for the coils of the educational and research tokamak MEPhIST, which includes capacitor banks, automated charging systems, state monitoring, synchronized switching of the banks to the toroidal and poloidal field coils, and the central solenoid, as well as protection systems. The technical aspects of the developed system are considered in detail from the standpoint of simplicity, scalability, fault tolerance, maintainability, as well as the possibility of modification. The implemented solutions, including the schematic diagrams, designed boards, and modules, can be useful to electromagnetic facilities with similar parameters and tasks.

A calculation methodology of the condensation rate of superfluid helium in the ultracold neutron source vessel for the PIC reactor is presented. The theoretical helium condensation rate of 5.36 L/h is obtained. To approve the calculation results, a full-scale experiment on helium condensation in a closed vessel was carried out. For the experiment the helium cryostat KG60/300-1 connected to the technological complex of superfluid helium production for the ultracold neutron source was used. The temperature in the cryostat was maintained by helium vapour pumping. The liquefaction rate during the experiment was 1.64 L/h, which confirms with good accuracy the proposed theoretical calculation model, which predicted the liquefaction rate to be 1.72 L/h. The time for the ultracold neutron source to reach the operating temperature regime was calculated to be 6.5 h at a total liquid helium consumption of 64 L. This estimation will be taken into account when planning the regular operation of the ultracold neutron source for the PIK reactor.

The results of development, creation, and use of a unified crystal station (CS) at the U-70 accelerator complex are presented. This station is used for proton beam extraction directly from the U-70 accelerator vacuum chamber using the channeling effect. The station performs fine angular and linear movements of crystal deflectors under harsh operating conditions: in a cyclic variable magnetic field of the accelerator, in high vacuum, and at high radiation dose rates. The components of the unified CS and their interrelation are described in detail. An automated control system for the unified CS is presented. The advantages of the unified CS over the previous generation CS are shown. The results of the unified CS operation with proton beams in U-70 sessions are presented.

The possibility of using a laser gyroscope with circular polarization of waves and a Zeeman frequency biasing for conducting various types of geophysical measurements is investigated. The first results of measuring the Earth’s rotation velocity by a Zeeman laser gyroscope with a perimeter of 20 cm in the underground laboratory of the BNO INR RAS are presented under conditions of maximum exclusion of external influencing factors − with thermal stabilization, shielding of electromagnetic fields, and minimization of seismic noise. An increase in the registration sensitivity by an order of magnitude (up to 10^–3 grad/hour) is noted compared to previously experiments in the urban ground-based laboratory. The possibility of continuous operation of the installation in a remote mode for more than 6 months is shown.

In this work, results of atom probe tomography and transmission electron microscopy of changes in the microstructure, grain sizes and chemical composition of the W–Cr–Y alloy as a result of vacuum annealing at temperatures of 1000°C and 1200°C, are represented. In the as-received condition of the alloy average grain size is equal to 1 µm and the grain boundaries are decorated with nanoscale (10 to 180 nm) particles enriched with yttrium and oxygen. Annealing causes recrystallization of the material with a decrease in the average grain size down to 100 nm. In addition, re-dissolution of yttrium oxides and the formation of nanosized clusters are observed, the composition and number density of which depend on the annealing conditions.

The paper contemplates the universal attributes of phenomena of dynamic failure, metals dispersion and full-developed turbulence. It is shown that critical behavior of non-linear systems of various physical nature is related to phenomena of self-organization, dynamic chaos and stochastic instability. This behavior is preceded by emergence (in systems) of scale-invariant time-space dissipative hierarchy structures, appearing through a cascade of bifurcation. Results of performed research of a number of nonequilibrium processes have shown that kinetics of dissipative structures emergence has properties of a chain of events, between which time intervals possess statistically self-similar distributions. The singularity spectrum of multifractal measure, describing a series of waiting times, is a characteristics of studied non-linear processes. From the point of view of physics one can address singularity spectrum f(α) as a quantitative characteristic of nonequilibrium systems, existing in the bifurcation transition processes.

The effect of high-fluence irradiation on the morphology and structure of highly oriented pyrolytic graphite UPV-1T by carbon ions with energies of 30 keV and helium ions with energies of 10 and 30 keV in the temperature range from room temperature to 600°C with fluence (1.0 – 4.5) × 10¹⁸ ions/cm^–2 has been studied experimentally. It is shown that implantation of helium ions leads both to the effects of dynamic annealing of radiation damage of the graphite crystal structure and to the effects of helium implantation in simulating the interaction of fusion products with graphite materials.

Possible products of hadron–nuclear interactions in a hadron beam at energies of of 5–10 GeV are secondary excited nuclei. During transitions from the excited state to the ground or another excited state, such nuclei emit photons with megaelectronvolt energies corresponding to the difference in the levels of the excitation transition of the nuclei. The energy spectra of deexcitation photons are the characteristic features of the excited nuclei. Therefore, the detection of these photons of gamma-ray nuclear transitions makes it possible to identify the nuclei formed in the final state of such a reaction. In turn, the correlation of the excitation spectra of secondary nuclei with the type and parameters of hadron systems emitted in the forward hemisphere of the reaction provides information on the dynamics of hadron–nuclear interactions. The first results of measuring the spectra of gamma-ray nuclear transitions in the Hyperon+ experiment in a test run using a set of statistics on hadron–nuclear interactions with a momentum of 7 GeV/c on a ¹²C carbon target by means of the gamma nuclear transition (GNT) spectrometer have been reported in this work. The obtained data can be interpreted as an observation of a series of gamma transitions of ¹¹C nuclei produced in the final state of events selected with the trigger for the interaction of the beam particles with the target

The superfast photoinduced dynamics of the reflection coefficient of superconducting composites based on layered REBCO (RE = Y) cuprates on a Hastelloy C-276 substrate has been studied in the temperature range of 5–200 K. It has been shown the ultrafast responses of the reflection coefficient to the excitation by femtosecond light pulses contain components caused by the normal and superconducting subsystems. The contribution from the normal component has a shorter relaxation time of ~0.2 ps, and its amplitude is proportional to the pump energy density in a wide range. The response of the superconducting component observed below T_c = 92 K has a longer relaxation time of ~2.5 ps, and the dependence of the amplitude on the pump energy density has a bend at ~14 μJ/cm². The temperature dependence of the response amplitude of the superconducting component corresponds to predictions of the phenomenological Rothwarf–Taylor model. According to the ultrafast laser spectroscopy data, the properties of thin-film YBa₂Cu₃O_7–x-based composites are very close to the properties of single crystals of these compounds