This article presents the results of modeling of the temperature field of the experimental assembly of the VCG-135 test bench to study the interaction between model corium and candidate metal-coolers (zinc, antimony and manganese) in the conditions of a severe accident.

The need for modeling is associated with the probability of metal melting in the discharge device due to the heat flow from the heating crucible of the experimental assembly. Thus, the purpose of the modeling was the justification of the integrity of the design of the metal discharge device during the production of liquid corium in the crucible of the experimental assembly.

The thermophysical model was created in the ANSYS software. The temperature field of the experimental assembly was obtained at the moment of obtaining liquid corium as a result of the modeling. An analysis of the results showed that metal in the discharge device wouldn’t reach the melting point. In this regard, the discharge device of the experimental assembly can be used in its current design for experiments conducting at the VCG-135 test bench.

At the same time, after the experiments, the thermophysical model was validated by comparing the calculated temperature values with experimental data. Validation of the model shows that the deviation of calculated and experimental temperature values at control points does not exceed acceptable limits (melting of the studied metal before interaction with corium). Thus, the developed thermophysical model can be used to justify further experiments on the VCG-135 test bench with the current experimental assembly.

Scintillation crystals CsI are widely used in nuclear physics and high-energy physics experiments. This work presents the study and analysis of luminescent properties of CsI:T1 crystals induced by irradiation with 230 MeV ¹³²Xe ions up to fluences (1·10¹¹–1·10¹⁴ ions/cm²) at 295 K (DC-60 accelerator, Astana, Kazakhstan). The research was conducted using optical absorption and luminescence spectroscopy methods, as well as time-resolved optically stimulated luminescence. The surface was studied using atomic force microscopy. A decrease in the intensity of the scintillation emission band at 553 nm and its light yield with increasing fluence was established. The conversion efficiency of the studied samples does not depend on fluence. Therefore, radiation damage does not affect the conversion efficiency of the CsI:Tl crystal. Track formation does not reduce the conversion efficiency of the CsI:Tl crystal but participates in the scintillation process through energy reabsorption from Tl⁺ centers, leading to light yield degradation.

The article is devoted to the study of methods for cleaning soils contaminated with petroleum products in the process of eco-tourism in order to preserve the natural environment. Bakoil-KZ biological product, created on the basis of hydrocarbon-oxidizing microorganisms, was used for soil purification. The use of this drug increased the degree of soil purification from petroleum products from 67.8% to 97.2%, with the most effective dosage being 2 g/kg. Morphological analysis and biotesting using watercress sprouts showed the absence of toxic properties in the purified soil. In experiments with the addition of Bakoil-KZ (1 g/kg and 5 g/kg), 84–82% and 88–90% of seeds germinated, respectively, which indicates soil purification. In polluted soil, only 19–23 seed specimens (38–46%) germinated without the addition of biological products, which indicates a slow self-purification process. The use of Bakoil-KZ is environmentally safe, prevents environmental disasters, requires fewer resources and allows land plots of various scales to be cleaned without damage to the ecosystem. This makes the drug an effective tool for soil restoration in touristically active areas. Effective management of soil pollution elimination and the use of modern cleaning methods, such as Bakoil-KZ biologics, play a key role in preserving the pristine nature of unique natural areas. The introduction of sustainable tourism practices and technologies will help minimize the negative impact on the environment and contribute to the conservation of biodiversity and ecosystems.

The article studies the level of rare earth metal pollution in urban and suburban garden plots of the city of Pavlodar. The main attention is paid to lanthanide pollution in the system “precipitation (snow) – soil – vegetables”: accumulation of metals in snow, their migration to soil and accumulation in plants. Pavlodar, as an industrially developed city, is exposed to emissions from industrial enterprises, transport and stove heating, which makes it vulnerable to rare earth metal pollution. The results show that the concentrations of the investigated elements in the solid phase of snow decrease in the following order (mg/kg) Ce (54.1) > La (27.9) > Nd (26.9) > Gd (5.8) > Dy (5) > Eu (1.4) > Ho (0.8) > Lu (0.3). In soils, metal concentrations decreased in the following order (mg/kg) Ce (33.28) > La (15.41) > Nd (14.72) > Gd (3.74) > Lu (1.3) > Ho (1.01) > Eu (0.82) > Dy (0.39). It was found that the content of metals in snow significantly exceeds their concentrations in soil, except for holmium and lutetium, whose concentrations are higher in soil. Background concentrations in the snow cover are on average 1.3 times lower than urban concentrations. The metals La and Ce have very low accumulation values for both potato and tomato, although there is a slight excess of the bioaccumulation factor for potato. These data are important for the development of measures to reduce pollution and protect public health.

The Impulse Graphite Reactor (IGR) is a unique nuclear facility in the world. The core of the research reactor is a stack of uranium-graphite blocks (fuel elements) enriched to 90 wt. % in ²³⁵U isotope. As part of the project on conversion of the IGR reactor to low-enriched uranium fuel, the specialists of the Institute of Atomic Energy (IAE) studied the possibility of immobilizing the first core in a cement matrix.

 Research into the immobilization process included both the formation of technical requirements for the uranium-graphite fuel matrix, determined by the conversion conditions, international and national standards, and the selection of the composition and ratios of the matrix components.

The paper presents the results of an analysis of modern achievements in the field of immobilization of radioactive waste and irradiated graphite, the formation of matrix acceptability criteria for the immobilization of highly enriched IGR fuel, and methods for determining whether the matrix properties correspond to the established criteria. The matrix compositions for immobilization of the irradiated fuel of the IGR reactor were selected experimentally, based on such characteristics of the cement slurry as bleed water, viscosity, setting time, uniformity of volume change, homogeneity and strength of the samples. To determine the above characteristics, the methods used to determine the characteristics of cement slurries were used and improved. They have proven their suitability.

The requirements used to select the composition of matrices for immobilization of spent uranium-graphite fuel of the IGR reactor turned out to be applicable and sufficiently constructive, and can also be recommended for solving issues of selecting the consistency of matrices for immobilization of other types of RW.

This paper presents the results of a study of radiation defect creation processes in Calcium Fluoride single crystals irradiated with X-rays, protons, and fast heavy ions of Xe¹³² and Bi²⁰⁹. The main method of the study is absorption spectroscopy. In the optical absorption spectra of CaF₂ samples irradiated with different types of ionizing radiation, broad intense absorption bands associated with electron and hole color centers and their aggregates are recorded. The analysis of the optical absorption spectra is performed in the Tauc and Urbach coordinates. The effect of fast heavy ion irradiation on the fundamental absorption edge and on disordering in the anion sublattice of the CaF₂ crystal is quantitatively revealed. The nature of the radiation-induced optical absorption in the 9.8 eV region induced by irradiation with Xe¹³² and Bi²⁰⁹ ions is discussed.

The paper studies the features of martensitic transformation during plastic deformation (uniaxial tension and compression) of austenitic steels 12X18N10T and AISI304 irradiated with thermal neutrons to a fluence of 3.7·10²⁰ n/cm² . The nickel equivalent and stacking fault energy values for 12X18N10T and AISI304 steels are calculated. It is established that AISI304 steel is more prone to martensitic transformation. The mechanical characteristics of the studied steels under uniaxial tension are determined. It is shown that with similar strength characteristics, the plasticity of irradiated AISI304 steel is twice as high as that of 12X18N10T steel. This fact is due to the more intense martensitic transformation during the plastic deformation of AISI304 steel.

The article presents new data on biology and ecology of invasive ichthyofauna of the Middle Irtysh basin on the territory of Pavlodar region. Using the literature data, the species composition of alien species inhabiting the upper, middle and lower reaches of the Irtysh River is summarized. In the Middle Irtysh basin, 15 invasive fish species belonging to 5 families and 13 genera are currently registered. The largest number of species belong to the carp family (9 species or 60%), salmonids include 3 species or 20%, other families are represented by one species. Only three species have acclimatized and entered the fishery in the Middle Irtysh basin: bream, carp (carp) and pikeperch. The share in commercial catches is from 15.7 to 27.7% for bream, from 0.2 to 1.5% for carp and from 0.8 to 1.3% for pikeperch. The largest number of caught bream individuals was registered in backwaters, carp in channels and lakes, pikeperch in Irtysh channels. The data on growth rate of these three fish species with the results of regression analysis are given. Data on the results of introduction of 11 more fish species are briefly summarized. It is concluded that spontaneous introductions sometimes lead to complete reorganization of biocenosis as a result of introduction of predator or food competitor, transfer of dangerous parasites or diseases. Most often, after a small “acclimatization effect” a water body not ready for the press of an introduced species becomes impoverished and becomes unattractive for fishermen and unpromising for commercial fish farming. Given that the problem of alien fish species is a serious environmental problem, its solution requires a comprehensive approach including scientific research, monitoring, management and educational programs.

Research of prototype fuel elements and fuel assemblies in in-pile tests are an integral part in substantiating the safety and operability of installations being designed, and are also necessary for validating the calculation codes. Despite the long service life and a large number of studies conducted in the IGR reactor, the capabilities of this reactor under conditions of implementing long-term experiments at minimum power are still not fully clear. This paper presents a substantiation of the possibility of implementing an experiment with power reactor fuel during the implementation of the long-term operation mode of the IGR reactor. Neutronic and thermal-hydraulic calculations were performed to determine the energy release in the fuel and structural materials of the experimental device, the time to achieve steady-state heat exchange between the fuel element and the cooling gas at a steady-state fuel element power level, and the temperature distribution in the test section at specified energy parameters.

This paper presents the results of plasma radiation loss measurements in the KTM tokamak obtained using a survey pyroelectric bolometer. The technical features and placement of the diagnostics of the KTM tokamak plasma radiation losses are presented. The first experimental results are demonstrated, which showed the operability of the diagnostics under KTM conditions. The total power of plasma radiation losses is calculated in the ohmic heating mode with a limiter configuration.

The article presents the study results of the effect of radionuclide and chemical contamination on the cytogenetic parameters of the bush grass (Calamagróstis epigéjos) growing on the Degelen mountain massif of the Semipalatinsk Test Site. The combined effect of ionizing radiation and the concentration of chemical elements in plants has been revealed. With an increase in the radiation dose from 5.0·10⁻⁶ to 2.5·10⁻⁵ Gy/h, minor changes are observed – an increase in the frequency of aberrant cells of meristematic rootlets of seedlings of bush grass (Calamagroustis epigéjos), however, all changes are within the margin of error. Certain changes in the frequency of aberrant cells are noted with an increase in the content of elements such as Cr, Mn, Li, Fe, the concentrations of which in the studied plants increase the MPC. In general, the maximum frequency of aberrant cells is about 8.8%. At the same time, chromosomal, chromatid and genomic types of chromosomal disorders were detected in plants.

To study the possible effect of ³Н on the cytogenetic parameters of plants, studies were conducted on plants growing in the ground water discharge zone with a high content of ³Н. Cytogenetic parameters of chee grass (Achnatherum splendens) have been studied. The effects of ³Н on the cytogenetic structure of plants were evaluated. In the course of research, the effect of ³Н on the cytogenetic effects of chee grass (Achnatherum splendens) at the studied concentrations in this experiment was revealed.

It is known from the world literature that for EPR spectrometry for emergency dosimetry, where doses from 0.5 Gy and higher are used, the quality and reliability of calculating the experimental dose depends on the parameters of recording spectra (accumulation time, microwave power).

This article describes the results of the development and application of a method for optimizing the parameter of recording EPR spectra on human tooth enamel, such as microwave power, but in the range of emergency radiation doses (from 1 Gy to 5 Gy), under conditions of a local radiation incident based on a biodosimetric laboratory. The results showed that the obtained experimental microwave power value of 5 MW is the most effective parameter for improving the quality of EPR spectra of human tooth enamel for a range of emergency radiation doses, even taking into account different types of spectrometers on which measurements are carried out. Optimization of the parameter for recording EPR spectra, in particular microwave power, improves the quality of the obtained spectra for the range of emergency radiation doses, even taking into account different types of spectrometers on which measurements are carried out.

This paper presents the results of experimental work related to the preparation of Nd₂Zr₂O₇ ceramics stabilized by Y₂O₃, the choice of which is due to the great prospects for their use as materials for inert matrices of dispersed nuclear fuel. During the conducted experiments aimed at determining the effectiveness of the influence of stabilizing additives in the form of Y₂O₃ on the change of structural and strength parameters of Nd₂Zr₂O₇ ceramics it was found that the increase in the concentration of stabilizing additives above 0.1 M leads to the formation of inclusions in the structure in the form of Y₂Zr₂O₇ grains, the formation of which is associated with the effects of polymorphic transformations in zirconium dioxide during high-temperature annealing. It was determined that the substitution of zirconium cations by yttrium cations leads to an increase in the concentration of oxygen vacancies in ceramics composition, the change in the concentration of which is also associated with phase transformations in the structure, arising at high concentrations of stabilizing dopant. At the same time, the optimum concentration of stabilizing additives is the concentration of 0.15 M, at which the ratio of structural and strength parameters has optimum values, determining their potential use as materials of inert matrices of dispersed nuclear fuel with high strength characteristics.

The article presents research data on the vertical distribution of radionuclides in bottom sediments of water streams at the former Degelen test location of the Semipalatinsk Test Site. As part of research, bottom sediments were sampled in the form of undisturbed cores. Based upon findings on the content of radionuclides in bottom sediment samples, histograms were plotted to describe the vertical distribution of radionuclides. The distribution of man-made radionuclides such as ²⁴¹Am, ¹³⁷Cs, ⁹⁰Sr and ³Н is addressed. The content of ²⁴¹Am is <DL in all collected samples. That of ¹³⁷Cs and ⁹⁰Sr varied from 3±1 to 180±20 Bk/kg and 10±1 to 13,000±2,000 Bq/kg, respectively. The content of ³Н was determined in two forms: in the free water (for bottom sediment samples from the Uzynbulak cr.) and in the tightly bound form. The content of ³Н in the free water was 6,400±640 Bq/kg to 21,000±2,100 Bq/kg, in the tightly bound form – 8±1 Bq/kg to 5,300±550 Bq/kg.

The paper deals with various aspects of registration of strong earthquakes with magnitude Mw≥7 in Turkey and China (2023 and 2024) by seismic arrays of the National Nuclear Center network in terms of view of the efficiency of their participation in seismic monitoring. The uncertainties of values of azimuths and travel times by seismic arrays. Recommendations are given for analysts on the use of different stations in processing data from the areas of the earthquakes under study. The records of infrasound stations were analyzed in order to detect signals from these strong earthquakes. Signals were found on station IS31 (Aktobe) from the Turkish earthquakes and station Makanchi from the Chinese earthquakes.

The study is devoted to the study of lanthanide niobates doped with bismuth ions, which are of interest as potential phosphors used in various fields of human activity, such as medicine, industry, and science. In this paper, an experimental study of the cathodoluminescence of niobates (Y,Lu,Gd)NbO₄:Bi³⁺, namely, spectral characteristics with time resolution, as well as the kinetics of luminescence attenuation for the main spectral bands, is carried out. The temperature dependence of the cathodoluminescence attenuation time for the YNbO4 sample is presented.:Bi³⁺ measured in the temperature range of 5–295 K with an interval of 10 K. The study of the kinetics of luminescence attenuation made in this study showed that at least three pronounced components are observed in the kinetics of attenuation at low temperature. Of the three components, the main contribution to the light sum is made by a slow microsecond component with a decay time in the range of 2–9 microseconds. However, the nanosecond kinetics of intrinsic luminescence of samples in the ultraviolet region of the spectrum is of particular interest. The presence of several fast components indicates the complex structure of this glow associated with the superposition of the glow bands of autolocalized excitons. The data obtained are of both scientific and practical interest in the further development of functional materials.

The paper presents a comprehensive description of the results of experimental work related to the study of the mechanisms of radiation damage accumulation during the irradiation with heavy Xe⁺ ions of the studied samples of Nd₂Zr₂O₇ ceramics in the unstabilized state, and stabilized with 0.15 M MgO and Y₂O₃, the adding of which according to the data of X-ray phase analysis leads to the formation of impurity inclusions in the structure in the form of MgO and Y₂Zr₂O₇ grains, which create a buffer protective layer in the intergranular space, the presence of which leads to an increase in resistance to radiation-induced processes of unstrengthening and reduction of thermophysical parameters. In the course of determining the dependences of changes in strain distortion resulting from the accumulation of structural stresses in the crystal structure and amorphization, which was determined on the basis of changes in the intensity of diffraction maxima, the equally probable influence of both processes at high-dose irradiation on the degradation of the near-surface damaged layer was determined, as well as the positive influence of stabilizing components on the inhibition of amorphization and strain distortion at high-dose irradiation. The analysis of changes in strength and thermophysical parameters of Nd₂Zr₂O₇ ceramics subjected to irradiation by heavy ions has shown that the addition of stabilizing additives in the form of MgO and Y₂O₃ to ceramics composition leads to increased resistance to radiation-induced processes of de-strengthening and thermal conductivity degradation caused by the accumulation of structural deformation distortions and metastable inclusions in the damaged layer.

The paper presents the results of investigation of the influence of the variation of the phase composition of composite (1−x)Si₃N₄ – xAl₂O₃ ceramics on the stability of strength properties in the case of irradiation with heavy ions Xe²³⁺ (230 MeV) at fluences10¹¹–10¹⁴ ions/cm² . The variation of the component concentration was chosen taking into account the possibility of obtaining composite ceramics with different phase ratio: Si₃N₄, Al₂O₃, as well as Al₂(SiO₄)O and SiO₂, the formation of which in the composition of ceramics is associated with the processes of thermal decomposition of Si₃N₄ during high-temperature annealing in an oxygen-containing atmosphere and phase transformations by the type of solid solution formation. The choice of the type of ions for irradiation is conditioned by the possibilities of simulation of structural damage processes leading to unstrengthening of the damaged layer, comparable to the impact of nuclear fuel fission fragments in ceramics – materials of inert matrices of dispersed nuclear fuel. In the course of the conducted studies, it was established that at irradiation fluences of 10¹¹–10¹² ion/cm² structural changes associated with the formation of single isolated structurally deformed inclusions do not lead to significant changes in the strength characteristics of ceramics, while small changes observed are associated with deformation distortions, the accumulation of which leads to destabilization of the damaged layer. In the case of higher irradiation fluences (above10¹² ions/cm² ), which are characterized by the formation of the effects of overlapping defect regions in the damaged layer, the ceramics of 0,4 Si₃N₄ – 0,6 Al₂O₃, in which, according to X-ray phase analysis data, the dominant phase is Al₂(SiO₄)O, the presence of which causes a large number of grain boundaries, which in turn leads to dislocation hardening and restraint of the disordering processes associated with deformation distortions of the damaged layer.

The article is dedicated to the study of MXene synthesis processes and their application as electrodes for supercapacitors. MXenes are two-dimensional nanomaterials with unique electrochemical properties, such as high conductivity and large surface area. The structure and physicochemical properties of the synthesized MXenes were investigated using analytical methods such as X-ray diffraction, scanning electron microscopy, and spectroscopy. The electrochemical activity of MXenes was studied in the context of their application in supercapacitors. The charge/discharge parameters, cyclic stability, and energy density of supercapacitors with MXene electrodes were examined. The results confirm the potential of MXenes as effective electrodes for supercapacitors. The obtained data indicate the rapid charge/discharge rates of MXene electrodes, making them promising candidates for use in energy-dense applications. This work contributes to a better understanding of the processes involved in MXene synthesis and their electrochemical characteristics, opening new horizons for the development of advanced supercapacitors with enhanced performance and longevity.

In the context of increasing industrial pollution and insufficient efficiency of traditional wastewater treatment methods, the issue of finding environmentally friendly and effective sorbents is particularly acute. Industrial dyes entering reservoirs change their color, are toxic and can pose a serious threat to human health and the ecosystem. The main difficulty lies in the fact that many dyes are resistant to biodegradation, which complicates their removal by standard cleaning methods. One of the promising materials that can solve this problem is nanocellulose, which has unique properties: high specific surface area, biocompatibility and biodegradability. Obtained from renewable sources, nanocellulose can become the basis for environmentally friendly water treatment systems. This study is aimed at studying the adsorption characteristics of nanocellulose synthesized from microcrystalline cellulose in relation to two stable water – soluble dyes – methylene blue and bengal rose. The results showed that nanocellulose effectively adsorbs methylene blue, reaching a sorption capacity of 35.87 mg/g, whereas for Bengal rose the adsorption capacity was 26.11 mg/g, which is explained by the difference in the types of interactions: chemical and physical adsorption. The methods of IR spectroscopy and X-ray diffractometry confirmed the structural changes that occurred during the synthesis of nanocellulose, which had a positive effect on its sorption characteristics. Morphological studies using optical and scanning electron microscopes have also demonstrated a high degree of dispersion and a developed porous structure of nanocellulose, which is important for improving its adsorption properties.

This article presents the results of modeling of the temperature field of the electric melting furnace of the “EAGLE” facility. The two-dimensional axisymmetric thermophysical model was created in the ANSYS software and the model was validated by comparing the calculated temperature values with experimental data during modeling. Validation of the model shows that the deviations of the calculated and experimental temperature values at the control points do not exceed the permissible limits. Thus, the developed thermophysical model can be used to justify further experiments at the “EAGLE” facility.

The paper provides data from the comprehensive studies of the levels and distribution pattern of radionuclide contamination in the ‘bottom sediments/soil-to-water-to-plants’ of water bodies at the Telkem site of the Semipalatinsk Test Site (STS). Research objects were water-filled craters Telkem-1 and Telekm-2 that resulted from excavation explosions. As part of these studies, sediments, soil, water, plants were duplicately sampled, in which the content of manmade ⁹⁰Sr, ^239+240Pu and g-emitting radionuclides were determined. As a result, a high level of radioactive contamination is currently found to persist in the ecosystem of water bodies at the Telkem site both for sediments ( ¹³⁷Cs, ²⁴¹Am, ⁹⁰Sr and ^239+240Pu) and water ( ⁹⁰Sr). Based upon findings, the distribution coefficient (K_d) for the ‘sediments-to-water’ system and the concentration ratio (CR_s-b) were calculated for the ‘sediments/soil-to-plants’ system. The distribution coefficient K_d for ⁹⁰Sr averages 10, for ^239+240Pu – 3.7·10⁵ . Plants’ capacity to accumulate from sediments and soil of aquatic ecosystems at the Telkem site, with respect to man-made radionuclides, decreases in the series C_Rs-b ⁹⁰Sr > CR_s-b ⁶⁰Co > CR_s-b ¹³⁷Cs > CRs-b ¹⁵²Eu > CR_s-b ²⁴¹Am > CR_s-b ^239+240Pu.