The article presents data on the content of artificial radionuclides ²⁴¹Am, ¹³⁷Cs, ⁹⁰Sr and ^239+240Pu in the plant cover of the ‘4’ site at test locations of radiological warfare agents (RWA). The excess of the maximum permissible level of radioactive contamination in forage plants is recorded for ⁹⁰Sr, the content of which varies from 7.6 to 18000 Bq/kg. The maximum value of overall dose rate for the herbaceous vegetation from radionuclides of interest is 220 µGy/day, with ⁹⁰Sr making the main contribution.

The article discusses whether special attention should be paid to long-wave ultrasonic radix systems used to detect corrosion and other defects on internal and external surfaces. This allows you to monitor the presence of corrosion and other defects in long pipes in hard-to-reach places.

Currently, relevant state industry standards are being developed that are used in the design and calculations of process pipelines, but for now it is better for expert institutions to pay special attention to diagnosing the technical condition. To do this, it will be necessary to use the most precise diagnostic solutions and provide a prognosis based on the entire system. 

The paper presents the development of a triple probe consisting of three tungsten electrodes with a diameter of 1 mm, intended for applications on a plasma beam installation (PBI). The appropriate measuring equipment and electrical wiring diagram have been selected. The probe has successfully passed the commissioning tests, during which key factors were identified that are important for accurate interpretation of the results and integration into the diagnostic system of the PBI. Experimental measurements of plasma parameters using a triple probe showed comparable results with a single probe: the electron temperature was 7 eV, and the plasma concentration was – 10¹⁶ m⁻³. The experimental results obtained confirm the correct operation of the developed probe and its use in experiments due to the simplicity of data processing compared with other types of probes.

This article discusses the current problems of forest and steppe fires in the Republic of Kazakhstan, their increasing frequency, impact on ecosystems and the economy, as well as on human safety. The necessity of using modern technologies in fire control and management, including unmanned aerial vehicles (UAVs), is discussed. In computer programming, the mathematical formula of the Stefan-Boltzmann law was used to model a thermal process as a physical phenomenon. As a result of calculations in the Python program, the dependence of heat flow on distance and smoke coefficient was confirmed. In the course of the study, the results of calculating thermal radiation based on the methodology for evaluating optical and thermal indicators for early fire prevention were obtained. It has been shown that the integration of UAVs and telemetry improves control over fire conditions, increases the accuracy of fire forecasting by promptly obtaining information in real time. This approach is proposed as an important way to protect ecosystems and human life.

With growing demands for environmental sustainability and efficiency in energy storage systems, nickel-metal hydride (Ni-MH) batteries continue to attract attention due to their safety and affordability. Optimization of components in such batteries is a priority task for improving their electrochemical characteristics and durability. One of the key components is anodes based on hydrogen-forming alloys, whose electrochemical properties, such as stability and capacity, significantly depend on the choice of binder material, which affects the structural integrity, conductivity, and resilience of the anode during cyclic charging and discharging. This paper investigates the influence of various polymer binders on the electrochemical properties of anodes based on LaNi₅ for Ni-MH batteries. The LaNi₅ alloy was synthesized using the solid-phase method from metal oxides, and its structure was confirmed by X-ray phase analysis. Electrodes were fabricated using three types of binders: polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVdF), and  polyethylene (PE). The electrochemical characteristics of the anodes were studied using cyclic voltammetry and galvanostatic charge-discharge methods. Results showed that the type of binder substantially affects the electrical conductivity, capacity, and cycling stability of the electrodes. Anodes with PTFE binder demonstrated the best electrochemical characteristics, high specific capacity (~200 mAh/g), and stability during multiple cycling. Electrodes with PE showed high initial capacity but rapid degradation during cycling, while anodes with PVdF were characterized by stable but low capacity. The study confirms that the choice of binder material is crucial for optimizing the performance of Ni-MH batteries. 

CFD modelling is a widely used tool for computer analysis in various fields, including reactor thermophysics. Thus, in the walls of the National Nuclear Center of the Republic of Kazakhstan, for the purpose of carrying out safety analysis of irradiated devices before their in-pile tests, the program ANSYS FLUENT is used. In addition to the safety analysis of reactor tests being conducted, this program is used for the selection of test modes, selection and justification of the diagram of the change of the power of the reactor, evaluation of the thermal state of individual structural elements, etc. The special feature of the Ansys Fluent software complex is the limited functionality of the graphical user interface (GUI), which is used by most users of the program at all stages of calculation analysis from preparation of the calculation model to processing of results. On the other hand, the text-based user interface (TUI) and user-defined functions (UDF) are used less frequently, although their combined use provides extensive opportunities for optimizing the computational process, improving result quality, and saving time and computing resources. In this regard, the task of developing a specialized software (program) that facilitates easy implementation of UDF files into calculation analysis has become urgent. The article presents a console-type computer program developed in Visual Basic environment for automatic generation of UDF files based on input data. Input data are files contain time and height (radial) energy distribution profiles. Advantages of the program: easy to use (no programming skills required), speed of creation of UDF files, accuracy of writing function (elimination of errors related to manual input of a large amount of data).

In recent years, cryoseismology has become an important area of research, providing new opportunities to study the dynamics of glaciers and their interaction with climate change. This interdisciplinary science, combining seismology and glaciology, opens up new perspectives for the analysis of processes in the cryosphere. In 2023, research of the Tien Shan glaciers using seismic and infrasound methods began at the National Nuclear Center of the Republic of Kazakhstan within the framework of the Targeted Financing Program (TFP) “Application of nuclear, seismic and infrasound methods for assessing climate change.” Three temporary seismic and infrasound stations have been installed in Kazakhstan, 70– 150 km from the large-scale glaciers of the high-altitude Tien Shan. Additionally, data from two stationary stations located at distances of 130 and 160 km from glaciers were used: the Shalkode station (130 km), which is part of the network of the National Scientific Center for Seismic Observations and Research of the Ministry of Emergency Situations of the Republic of Kazakhstan (NSCSOR MES RK), and the Podgornoye station (160 km), owned by the Institute of Geophysical Research The National Nuclear Center of the Republic of Kazakhstan (IGR NNC RK). These stations, located on rocky foundations, have demonstrated high efficiency in recording weak signals of glacial activity. Research confirms the importance of cryoseismological approaches for analyzing glacial processes and their relationship to climate change.

This article presents an analysis of the dependence of phase and morphological changes in the powder composition of the Mg-Ni-Ce system on the parameters of mechanical synthesis. During the mechanical synthesis process, it was found that, in addition to acceleration and duration parameters, the ratio of powder to milling balls has a significant influence on changes in the structural characteristics of the material. The results of the microscopic analysis showed that with a powderto-ball ratio of 1:10, the average particle size in the synthesized mixtures is 13.76 µm. At the same time, when applying a ratio of 1:30, the particle size decreases to 7.59 µm. It was established that magnesium is the primary phase in all samples. However, at a ratio of 1:30, the formation of the hexagonal crystal lattice of the MgNi phase and the emergence of the CeNi phase are identified.

The present article provides review of seismic certainty and knowledge of Kazakhstan territory. The certain changes have been introduced to the picture of active seismicity of Western Kazakhstan once updated map for seismogenic zones was issued in Year 2016. Previously, seismic hazards had been mainly associated with potential earthquakes from a highly active zone crossing the Caspian Sea from the Kopet Dag to the Caucasus. Moreover, up to date mentioned area had been considered as an aseismic zone with no practical efforts to investigate seismic activity. However, recent geodynamic events demonstrated quite noticeable record of the earthquakes in Western Kazakhstan attributed by some researchers to technogenic impact from extensive production development of petroleum and gas deposits. The experts insist on arrangement of seismic arrays’ grid to ensure more accurate verification of earthquakes and mitigate errors in geodynamic events parameters estimation.

The joint effort of Michigan State University (USA) and Institute for Geophysical Researches of the National Nuclear Center of the Republic of Kazakhstan undertaken in the south-eastern part of Mangistau Province, east of the Mangistau Peninsula, resulted with deployment of Mangystau array (MSUAR) – Mangistau Temporary Network of Seismic Arrays aimed to run feasibility study to substantiate location of a new seismic array in Western Kazakhstan and further investigate seismicity of the region.

The numerous criteria and factors had been identified based on the findings of collection and analysis of geologicalgeophysical, seismological, geomorphological data including interpretation results and mentioned criteria and factors shall be further used to address wide range of challenges.

Modeling of nuclear reactors is one of the important steps in ensuring safety and optimizing their characteristics. This work is devoted to assessing the characteristics of the core of the EPR reactor under its various operating modes in order to consider this type of reactor as a possible candidate for the construction of a nuclear power plant in Kazakhstan. The research culminated in the development of a computational model of the EPR reactor and the introduction of analytical methods to obtain additional data. The research was carried out using the Monte Carlo method developed in the MCNP program and designed to analyze in detail the neutron-physical processes occurring in the rector's core. The article presents a description of the EPR reactor, a research methodology, a computer model, simulation results and a comparison of calculated data with literature data. 

In this article, the electronic and magnetic properties of half-Heusler alloys CrNiZ (Z = Sb, Sn) were investigated by a quantum chemical method based on density functional theory (DFT). Generalized gradient approximations (GGA) and meta-GGA exchange-correlation functionals (SCAN) were used in the calculations. According to the results obtained, it was found that while the CrNiSb alloy exhibits a half-metallic character, the CrNiSn alloy has a metallic character. The Meta-GGA (SCAN) functional was chosen as a method for a more accurate description of the electronic structure of CrNiZ alloys. In addition, it was found that the magnetic moment of the CrNiSb alloy is 3 µB, which corresponds to the Slater-Pauling rule. 

The mechanisms of creation of a new combined electron-emissive state at 2.95 eV, 3.1 eV, 2.6–2.7 eV and 2.25–2.4 eV, which is a pre-decay state for energy transfer from the matrix to the emitters, were investigated in the CaSO₄ −Bi  phosphor. Combined electron-emissive states are formed from intrinsic SO₄³⁻ − SO₄⁻ and impurity Bi²⁺ −SO₄⁻ electronhole trapping centers according to studying via spectroscopic and thermal activation methods. In turn, the intrinsic and impurity electron-hole trapping centers are created during excitation of the anionic complex SO₄²⁻ as a result of charge transfer from the matrix to impurities (О²⁻ −Bi³⁺ ) and neighboring anions (О²⁻ − SO₄²⁻ ). It is shown that the energy accumulated in the intrinsic matrix during external irradiation in the form of a combined electron radiative state of SO₄³⁻ and Bi²⁺ decays as a result of the recombination process and is transferred to impurities.

To date, the corium research is one of the main issues in the framework of improving nuclear safety and is one of the tasks of conducting a successful procedure to eliminate the consequences of an accident with a core meltdown at the NPP. One of the important tasks for the procedure of eliminating the consequences of an accident at the NPP is to understand the physical state of the core melt of an emergency reactor (corium) in order to make decisions on its removal from the contents and further handling. The difficulty in assessing the structure and properties of the corium, which undergo the changes as a result of cooling with water and prolonged exposure in a melt content or trap (the process of corium “aging”), is in its high radioactivity.

Corium includes elements of the core (uranium fuel, zirconium cladding), elements of metal structures, structural materials, concrete, etc. There are five known cases of non-design accidents with the formation of corium: at the reactor of the Three Mile Island-2 NPP (USA, 1979), at the Chernobyl NPP (Ukraine, 1986) and three cases of corium formation were observed during the accident at the Fukushima -1 NPP (Japan, 2011). All these incidents have shown the relevance of improving safety systems at nuclear installations, as well as the need to study the properties of corium in order to work with it.

Due to the high radiation hazard, the studies of the corium properties are carried out on model samples. The model corium in the “Institute of Atomic Energy” Branch of RSE NNC RK can be obtained both under laboratory conditions and at the experimental benches of the Institute. The corium properties are different and depend on the initial composition of the charge (components modeling the core and structural materials) and the conditions for modeling an out-of-design accident (melting temperature, the principle of the melt cooling, the presence of residual power density, the method of retaining the melt, etc.).

The paper presents the results of the analysis of modern achievements in the field of corium study, as well as methodological recommendations for the study of corium aging processes based on the experience of foreign specialists (Japan, Russian Federation) [1–4] and own long-term developments of the specialists of the branch “Institute of Atomic Energy” RSE NNC RK.

The methodological recommendations given in this paper can be used directly to study the process of changing the corium properties under various conditions, as well as to predict the aging process for a given period of its exposure in the content of a reactor installation or a subreactor melt trap.

In the work, using the method of in-situ measurements of X-ray diffraction patterns, the stability of the phase composition, as well as the structural parameters of Si₃N₄ ceramics, was studied in a wide temperature range from 25 to 1400 ℃, covering the range of operating temperatures during the use of ceramics in extreme conditions. The main aim of this study is to determine the phase and structural changes in Si₃N₄ ceramics as a result of thermal effects, as well as to determine the role of thermal effects on the structural features of ceramics associated with thermal expansion. During the experiments it was established that thermal heating of samples in a vacuum does not lead to the initialization of oxidation processes characteristic of heat treatment of Si₃N₄ ceramics in air, which are accompanied by the formation of the oxide phase SiO₂. At the same time, the assessment of the weight contributions of the established phases in the composition of ceramics revealed the absence of any significant alterations in the phase ratio in the entire measured range of annealing temperatures. Based on changes in the volumes of the crystal lattice of both phases in the composition of Si₃N₄ ceramics, the value of the thermal volume expansion coefficient was determined depending on the exposure temperature. It was found that the average value of the β_V(T) coefficient is about 8.5–10·10⁻⁶ K⁻¹ for both established phases in the composition, while in the case of the α-Si₃N₄ phase, the change in the β_V(T) value has a clearly expressed dependence on the heating temperature.

The paper considers the influence of the temperature of heating under irradiation by heavy ions of composite ceramics on the processes of structural unstrengthening and disordering caused by the accumulation of radiation damage. The variation in irradiation temperature ranged from 300 to 1000 K, which made it possible to simulate radiation damage processes that were as close as possible to real operating conditions. The studies revealed a direct correlation between the changes in the degree of unstrengthening and bending strength disorder and the amount of volume-strain swelling of the crystal structure, as well as the contribution of thermal effects to the degradation of structural and strength properties of ceramics. According to the obtained data, it is established that the increase in the concentration of amorphous inclusions in the damaged layer, the presence of which has a direct dependence on both irradiation fluence and temperature, leads to a more expressed degradation of strength characteristics, indicating destabilization of ceramics resistance to the processes of unstrengthening at high-dose irradiation. Moreover, the degree of unstrengthening has a direct dependence on the irradiation temperature, which in case of considering the applicability of these ceramics as inert matrix materials requires consideration while predicting their operation lifetime. It was determined that the increase of irradiation temperature leads to more distinct destabilization of strength properties, in particular, decrease of hardness and bending strength at fluences of 10¹³–10¹⁴ ion/cm², the degradation of which exceeds the permissible values of 5% decrease from the initial values.

The paper presents the assessment results of changes in the structural, strength and thermal parameters of cer-cer composite ceramics based on oxide compounds to radiation damage caused by high-temperature irradiation with heavy Kr¹⁵⁺ and Xe²³⁺ ions. During the studies conducted, relationships between changes in structural parameters caused by deformation distortion of the crystalline structure and an increase in its volume, with the assessment results of the degradation of strength and thermal parameters, were established. It was determined that an elevation in the irradiation fluence leads to a cumulative effect of degradation of the properties of ceramics, while in the case of irradiation with heavy Xe²³⁺ ions, the effect of structural disordering and degradation of strength and thermal parameters is more pronounced than in the case of irradiation with Kr¹⁵⁺ ions. This phenomenon is caused by differences in the value of ionization losses of incident ions, as well as the size of damaged areas that arise as a result of the interaction of incident ions with the crystalline structure of the damaged layer. At the same time, the most stable to radiation-stimulated softening processes are two-phase Al₂O₃ – ZrO₂ ceramics, in which the presence of interphase boundaries leads to a growth in resistance to softening and destruction under high-dose irradiation. The presence of interphase boundaries acting as barriers that stop the diffusion of point and vacancy defects and reduce the degree of structural disorder of the damaged layer is considered as a mechanism for containing radiation damage in the case of two-phase ceramics. 

Photoinduced splitting of water using photocatalysts in the form of nanoparticles is a promising and simple way to produce environmentally friendly hydrogen. In this paper, we investigate the potential of modified barium titanate (BaTiO₃), an inexpensive perovskite oxide obtained from precursors widely distributed on earth, to develop effective electrocatalysts for water oxidation using first-principles calculations.

It has been shown that the BaTiO₃(001) surface terminated with TiO₂ is more promising in terms of its use as a catalyst. After replacing Ti with Rh, the dopant ion can take over part of the electron density from neighboring oxygen ions. As a result, during the oxidation reaction of water, rhodium ions can be in an intermediate oxidation state between 3+ and 4+. This affects the adsorption energy of the reaction intermediates on the surface of the catalyst, reducing the excess potential.

The article is devoted to the development and creation of research cells for solid oxide fuel cells (SOFCs) designed to study their characteristics at various temperatures. The primary focus is on the use of high-temperature glass sealants that ensure the hermeticity of the structure. The paper describes the materials and methods for fabricating model fuel cells, including various combinations of electrolytes (YSZ, ScSZ, GDC) and electrodes (NiO, LSM). The design of the research cells incorporates electrochemical sensors, providing precise control over the composition of the gas mixture entering the active zone, with deviations not exceeding 0.5%. The results of current-voltage characteristics of the model SOFCs in the temperature range of 700–950 ℃ showed that an increase in temperature leads to a reduction in ohmic losses and improved kinetics of electrochemical reactions. The maximum power density is achieved at higher current densities with increasing temperature, which is attributed to enhanced material conductivity and improved electrode activity. At lower temperatures, limited cell efficiency is observed due to increased electrolyte resistance and reduced electrode activity. The developed research cells demonstrated high reliability and reproducibility of data, enabling their use in optimizing the material composition and structure of SOFCs. The obtained results confirm the potential of the proposed methodology for the development of highly efficient fuel cells.

The article presents the results of a study on the effect of Sr-90 on the conductive tissues of the common bean (Phaseolus vulgaris) in three consecutive generations grown in a model experiment. The absorbed dose rate from internal and external radiation for each common bean generation during the growing season averaged 9.5·10⁻¹ G and 1.7·10⁻⁴ G, respectively. The thickness of the conductive tissues in 3 consecutive generations of beans varied in descending order: 1^st generation > 2^nd generation > 3^rd generation ≥ control group (p<0.05). Collectively, the established increase in the thickness of the conductive tissues of the stem and leaf in the 3rd generation of beans is a response to stress and is aimed at maintaining homeostasis at the tissue level of the biological organization. The obtained patterns characterize the mechanisms of plant adaptation to a high level of soil contamination with Sr-90 radionuclide.

This paper examines the use of mathematical modeling to enhance the safety of nuclear power plants (NPPs). The study demonstrates that reaction time plays a crucial role in accident prevention: if an operator takes action within 30 seconds, the probability of preventing an accident is 95%, whereas a 5-minute delay reduces this probability to 30%. The impact of preventive maintenance and system redundancy on reliability is also analyzed. Without maintenance, the probability of equipment failure after 1000 hours of operation reaches 40%, whereas regular inspections reduce this to 15%, and redundancy further lowers it to 8%. Additionally, cascading failures were studied, showing that as the number of interdependent components increases from 3 to 10, the risk of total system failure rises from 15% to 80%. The paper provides practical recommendations for improving NPP reliability, including the automation of monitoring, the implementation of predictive algorithms, and the use of machine learning for failure forecasting.

This paper presents research into the distribution of radiocarbon in the soils of forest ecosystems of the Republic of Kazakhstan. The forest compartments of the Beskaragai area of the Abai region and the Burabai area of the Akmola region were selected as research objects. For research, samples of forest litter and soil were collected layerwise, in which the content of ¹⁴C was determined by liquid scintillation spectrometry. The research findings showed that the soils of the Beskaragai area exhibit an elevated content of ¹⁴C gradually decreasing from top to bottom. This is due to radioactive contamination caused by the tests conducted at the Semipalatinsk Test Site. The content of ¹⁴C in the soils of the Burabai area is below the detection limit.

Shell effects are most pronounced in mass and energy distributions of fission fragments at the lowest excitation energy of compound nucleus. To study shell effects the mass and energy distributions of fission fragments of ²⁴¹Am* compound nucleus in ²⁴⁰Pu(p,f) reaction were measured at incident proton energy of 7 MeV. This energy is substantially lower than coulomb barrier for this reaction leading to very small reaction cross-section and low speed of data acquisition. Due to that the results we provide are only preliminary and final results will be provided later after acquisition of additional statistics. The measurement was carried out by 2E method on U-150M accelerator of Institute of Nuclear Physics, Almaty city, Kazakhstan. The acquired preliminary mass and energy distributions were decomposed into yields of separate fission shells assuming that the shape of mass yield of each fission mode is gauss distribution.

NNC RK Bulletin. 2024; 4(100):119–127

On page 125, at the end of the “Conclusion” section, the following paragraph of text should be added: “ Исследование финансируется Комитетом науки Министерства науки и высшего образования Республики Казахстан (No. BR21882237).”

The original article can be found at https://doi.org/10.52676/1729-7885-2024-4-119-127.