The work is devoted to the experimental and theoretical study of the effect of external induced convection on heat transfer from horizontal heaters under conditions of pool boiling of saturated water at atmospheric pressure. It is shown that induced convection significantly affects the heat transfer in the natural convection mode and practically does not affect the heat transfer in the nucleate boiling mode. The proposed model for calculating the heat transfer coefficient for the intensification of heat transfer due to external induced convection is in good agreement with experimental data.

The long-lived minor actinides (MAs) are the major contributors to the long-term radiotoxicity of spent fuel. Therefore, the transmutation of these MAs is considered as an alternative way to the direct disposal. Up to now no definite internationally recognized quantitative criterion of MAs transmutation efficiency was worked out, although this would be highly desirable. The absolute and relative total mass reduction of MAs are completely inadequate. We introduce a new criterion for transmutation efficiency of MAs in nuclear reactors and demonstrate its efficiency by comparing two molten salt reactors; the Single-fluid Double-zone Thorium-based Molten Salt Reactor (SD-TMSR) and the Small Molten Salt Fast Reactor (SMSFR). The proposed criterion takes into account the mass of all useful MAs, short-lived MAs, and short-lived fission products (FPs). The proposed approach merges the advantages of both homogeneous and heterogeneous approaches. We introduce a new approach to load MAs into the SD-TMSR and SMSFR. The change in the actinides and FPs mass has been calculated using SERPENT-2 code. The results show that the transmutation efficiency of 241Am, the prime candidate for transmutation, in the SD-TMSR is much higher than in the SMSFR. After 1500 days of radiation, the transmutation efficiency reaches 82.6% for SD-TMSR, however, for SMSFR it reaches 52.5%.

The purpose of this work is to describe the methods of analytical control of americium-241 and uranium in the process of their sorption on solid-phase extractant based on TODGA to obtain reliable results of mass transfer of americium-241 and uranium. The reliability of the obtained research results is ensured by the presence of a quality management system in the laboratory, exactly: the correct application of analytical control measurement methods, the use of verified analytical control measuring instruments, the use of advanced information technologies, and proven software for data processing.

In this paper, we introduce the concept of a new generalized one-dimensional channel – the ring layer. It includes a solid cylindrical wall and a liquid or gas layer adjacent to the wall, on the outer surface of which there is no pulse flow and a maximum speed is achieved. By definition, there are two ring layers: outer and inner. For each of them the article presents the calculation formulas of their geometric characteristics: area, wetted perimeter, hydraulic diameter, curvature of the layer. Depending on the curvature parameter of the annular layer β the channel can pass into a flat, round tube or an equivalent cell of rod bundles of different relative pitch. The velocity distribution in the turbulent flow of the coolant in annular channel is described by the universal velocity profile. Relations are obtained for determining the ratio of the maximum speed to the average, the deviation of the maximum speed from the average, the coefficient of hydraulic resistance of the channel depending on its curvature. Depending on the value of the curvature parameter β, they generalize data on the turbulent flow regime of a liquid or gas in a flat channel, a round pipe, an annular channel and bundles of rods with a smooth and rough channel surface. It is indicated that for a given shape and roughness geometry, it is necessary to know the dependence of the second constant of the logarithmic profile on the dimensionless height. Resulting calculation formulas can be used in engineering calculations of the hydraulics of heat exchange equipment.

The new coordinate-tracking detector TREK, based of drift chambers, is being developed at NRNU MEPhI for studies of ultrahigh energy cosmic rays. To reconstruct events with a high multiplicity from the data of drift chambers, the histogram method is currently used, which is designed to search for parallel tracks. However, we observe afterpulses in the experimental data obtained using a coordinate-tracking unit based on drift chambers (CTUDC). The afterpulses lead to fake track reconstructions. To solve this problem, a new method is being developed using deep learning. The paper presents the results of the development of this method and its application to simulated data.

The observed parameters studied in experiments on the collision of relativistic nuclei depend on the initial conditions, which cannot be determined experimentally. The standard method for determining the relationship between observables and theoretical initial state parameters is based on the Glauber model. We present the dependences of the parameters of the initial conditions of the heavy ion collisions on the input parameters of the Monte Carlo Glauber model, such as the inelastic cross section of the nucleon–nucleon interaction, which depends on the collision energy, and the nuclear density.

The paper presents a comparison of three methods for identifying neutrons in scintillators based on ZnS with ⁶Li and ¹⁰B: charge integration method, pulse gradient analysis and simplified digital charge collection. A quality factor is used for comparison. It is calculated by the distribution of distances from the event coordinate to the discrimination curve. It is shown that charge integration method is observed to provide the best discrimination performance in this research.

The NEVOD experimental complex includes several installations for the joint study of various components of extensive air showers (EAS). One of the installations is the calibration telescope system (CTS). This installation is used for calibration of the measuring modules of the Cherenkov water detector, as well as for recording the electron-photon and muon components of the EAS. The reconstruction of the EAS parameters according to the CTS data aims to improve the capabilities of the entire experimental complex for studying showers in the region of primary particle energies from 0.1 to 10 PeV. The main task of reconstruction is to determine the coordinates of the EAS axis position using the maximum likelihood method. The iterative simplex method of Nelder-Mead is used to find the optimal values of the parameters. The accuracy of the reconstructed parameters was estimated on simulated events. The simulation was based on the Nishimura-Kamata-Greisen lateral distribution function for EAS charged particles. The results of reconstruction of the parameters of the EAS registered in the upper plane of the SCT are presented.

The process of the formation of the martensite phase in tensile tests of austenitic steel was studied by the scanning contact potentiometry method (SCP). Steel sample, that was produced from “EI847” steel, was tensile tested at room temperature over a wide range of loads (50–60 MPa) for several weeks at intervals of one to five days when the sample was unloaded. Three stages of formation of the martensite phase have been found. Potentiograms and spectrograms were constructed and analyzed in the stress range from 150 to 650 MPa. The method for spectral analysis of potentiograms has been developed, which improves the image quality of reflections of structural inhomogeneities.

The paper studies the relationship between particle precipitation from the Earth’s radiation belt and cosmic gamma-ray bursts. For this purpose, experimental measurements of charged cosmic ray fluxes in the PAMELA experiment and observations of gamma-ray bursts by the Fermi observatory are used. Both instruments simultaneously operated in low-Earth orbit between 2008 and 2016. For the moment of time of each gamma-ray burst detected by the Fermi observatory in the specified time period, the counting rate of the PAMELA instrument detectors was analyzed. To search for a possible signal from the interaction of a gamma-ray burst with charged particles of near-Earth space, annual background maps of the counting rates of time-of-flight system detectors are constructed. The difference between the background counting rate and the counting rate at the moment of arrival of the gamma-ray burst (in the time interval a few minutes before and after) was analyzed. We found several cases where there is a significant deviation of the counting rate from the background value at the time of the arrival of the gamma-ray burst, which lasts up to 5−10 min after that.

The article presents a method for identifying light nuclei in cosmic rays from PAMELA spectrometer measurements of magnetic rigidity and energy losses of particles along the track in the time-of-flight and tracking systems. Nuclei from hydrogen to boron inclusive are separated by analyzing energy loss distributions in detector planes caused by their fluctuations. The identification quality estimate and the error (misidentification) probability are also calculated for each nucleus on the basis of Geant4 simulation data.

The stereotactic proton therapy facility at the SC-1000 synchrocyclotron, Petersburg Nuclear Physics Institute, is described. The "shoot-through" irradiation method is applied: intracranial targets are exposed to a 1000-MeV horizontal proton beam in combination with a rotational irradiation technique. Particular attention is paid to the modernization of the facility and the bringing it to modern high-tech medical care standards. The design project of a proton therapy table is described. The features of the developed software for control of the facility and track the parameters of the proton beam, which allows precise positioning, as well as dynamic movement of components for the implementation of complex irradiation plans are considered. It has been found that a unique irradiation technique requires the development of an unparalleled threedimensional treatment planning system to simulate the irradiation conditions, calculation of dose distributions, and selection of the optimal irradiation plan taking into account dose-constraints in organs of risk. It is also required to develop A verification system should also be developed to ensure the quality assurance of proton stereotactic therapy.