It is investigated approximate method for the calculation of the neutron spectra. It is shown the calculation of different relaxation length of the neutron in the matter. The method is given for the calculation of the relaxation length of the
neutron gase temperature on the basic diffusion length and the relaxation length for neutron flow obtained from the experiment.
The Institute of Atomic Energy (IAE) Branch of the Republican State Enterprise national Nuclear Center of the Republic of Kazakhstan has been updating automated control subsystem of the information-control system at its experimental test bench EAGLE since the beginning of 2020. As part of modernization, IAE has installed new equipment and implemented primary adjustment of moduli and extension racks by means of specialized Modbus Utility software included in the delivery. In addition, IAE has developed algorithms to receive and transmit data onto moduli, directive screen and provide information regarding the state of test-bench automatic units. This work will result in the improvement of monitoring, recording and display of experimental information related to the state of EAGLE automated control units.
In this work, we have carried out computer simulation using the density functional theory of the magnetostrictive properties of Ni and Nd modified FeGa alloy. It is shown that the experimentally observed decrease (increase) in the coefficient λ001 upon the addition of Ni (Nd) dopants is associated with an increase (decrease) in the antibonding character of the chemical bond between iron atoms in the first and second coordination spheres of the dopant atom as compared to the situation when, to enhance the magnetostrictive effect gallium was used. The electronic structure of the FeGa alloy is theoretically investigated by the methods of density functional theory. The work is aimed at explaining the difference in the change in the magnetostrictive properties of the material when using different types of alloying elements. The effect of interest is explained by the change in the nature of the chemical bond between the iron atoms of the first and second coordination spheres around the impurity atom due to the dopant. An increase in the bonding nature of the electron orbitals between these atoms leads to a decrease in the magnetostrictive effect, and its weakening leads to the opposite effect.
The paper provides tritium (3Н) concentrations in atmospheric air in the venues of tunnels at the «Degelen» testing site of Semipalatinsk Test Site (the STS). Tritiated water (НТО) and gaseous tritium compounds (НТ) in air environment were registered in air environment both at the «Degelen» testing site and beyond its boundaries. Based on the data obtained, contribution of 3Н entering with air into radiation exposure of personnel and population was determined through the example of the «Degelen» testing site. It was found, that contribution of 3Н to radiation exposure of the personnel (inhalational intake), carrying out works in the venues with the maximum concentration of 3Н in the air does not exceed 1%. Contribution of 3Н to the radiation exposure of population, performing economic activities beyond the «Degelen» site, in the venues of streamflows with high concentration of 3Н in water and in air will be approximately 10%.
Two sets of Heusler alloys of the type Mn2Co1−xVxZ (Z = Al, Ga) were studied by computer simulation methods using density functional theory. Changes in the absolute value and direction of the lattice ions' magnetic moments are investigated depending on the chemical composition. Topological analysis of the charge distribution on the crystal lattice atoms is carried out to explain the results obtained. It is shown that changes in the magnetic properties are determined by the system's charge ions' states. The fundamental difference between Al- and Ga-containing alloys is Ga ions' ability, in contrast to Al ions, to change their charge state as the vanadium concentration increases, which gives an additional degree of freedom for modifying the electronic structure of the studied compounds.
The article reveals the concept of biological dosimetry as a leading field of research in the modern scientific space of radioecology, its essence and basic laws. Information about the latest biodosimetry studies carried out at the IRSE - testing of the prototype of the “dose-effect” calibration curve, improvement of the basic technique (analysis of chromosomal aberrations in human peripheral blood lymphocytes), accumulation of statistical data on the background standard frequency of chromosomal aberrations in different regions of Kazakhstan. The relevance and research objectives of this topic are also indicated. A review of the experience of research in the field of biological dosimetry in Kazakhstan is carried out, its significance for the development of the country's science is indicated, and the prospects for development and research in this direction are revealed.
The article describes a method for obtaining samples of a heat-resistant nickel-based alloy, followed by applying a composite coating. Model high-temperature alloys based on Ni-Cr (20Kh23N18) with a given structure have been obtained. Manufacturing of experimental castings included the following operations: heating of the measured charge billet of the finished alloy; heating to a temperature of 1600 °C and melting the metal in a vacuum of 10−2–10−4 Pa; pouring the sample into a mold at a metal temperature of 1480–1530 °C, the mold temperature was 950–1000 °C. Mathematical model of the ingot formation process was calculated, reflecting the crystallization sequence and the continuity of the volume supply along the height, the temperature field of the composite shell, have been performed. The developed mathematical model showed that during the production of ingots, the melt should be poured at a constant level in the funnel. To apply a two-layer coating with inner metal and outer ceramic layers on the prepared surface of the matrix of the heat-resistant 20Kh23N18 alloy: Cr/Al/Co + ZrO2-Y2O3, an ion-plasma technology was proposed.
The paper provides results of research of concentration and distribution of artificial radionuclides in the components of forest litter and in the top soil layer of the pine forest of Priirtyshie long after nuclear tests at the territory of Semipalatinsk Test Site (the STS). Minimum and maximum values of specific activity were determined for 137Cs, 90Sr, 241Am, 239+240Pu in the soils researched as well as in mineral and organic components of litter. Series of radionuclides were formed depending on their ability to be accumulated in the top layer of soil and in the components of forest litter. Dependence between concentrations of 137Cs, 90Sr, 241Am, 239+240Pu in the litter and its thickness was determined.
One of the features of corium is the presence of residual energy release. Induction heating is used as a method for physical modeling of residual energy release at the LAVA-B installation. The article is devoted to the induction heating of corium during experimental studies of its interaction with heat-resistant materials at the Lava-B installation. The results of the analysis of parameters that affect the efficiency of the induction heating system, and determine the optimal conditions for increasing the power and efficiency of simulation of residual energy release are presented. As a result of this work, some conclusions are made about the necessary conditions for increasing energy release in corium and the efficiency of induction heating as a method of physical modeling of residual energy release in corium
Due to the absence in the Republic of Kazakhstan (RK) of an organization that tests transport packaging sets (TUK) in the course of work relating to management of radioactive waste (RW), spent nuclear fuel (SNF) and nuclear materials (NM), RK enterprises have troubles in obtaining permits for the use of TUK for various purposes. Currently, this issue is achieved in one of the following ways:
– certificates-permissions for TUK designs are issued abroad and after they are received on the territory of the country that issued the certificate, the validity of certificates-permissions is expanded over the territory of the Republic of Kazakhstan;
– exemption of TUK from the requirements of regulatory legal acts (RLA). This solution is not always applicable, since it limits the amount of transported material (e.g., the mass of fissile material in one TUK is not more than 400 grams, provided that each individual package in the TUK contains maximum 15 grams of fissile NM) and is not applicable to all transported materials
The availability of the own test base for TUK will set free the Republic of Kazakhstan from the need for foreign assistance in TUK certification. The bench complex (laboratory) will provide conditions for closing the TUK production process in the Kazakhstan and will create competition in the world market for these services.
The paper considers an experimental device with a neutron converter [1], which provides a change in the neutron spectrum of the IGR reactor from thermal to fast. Successful testing requires a number of thermophysical calculations that sufficiently accurately simulate the thermal state of the experimental device and make it possible to justify the safe conditions of the experiment. The paper presents the results of non-stationary calculations of the thermal state of an experimental device with a neutron converter with energy release both in fuel and in structural materials that simulate nuclear fission energy in fuel elements and the effect of instantaneous and delayed gamma radiation on structural materials.
In the IAE Branch RSE NNC RK at the VCG-135 test-bench within the framework of the commercial projects and scientific and technical program entitled “Study of the corium prototype properties of various compositions” small-scale experiments are carried out to obtain corium prototypes of various compositions. Physical and mechanical properties, phase and elemental composition of corium prototype samples resulted from high-temperature experiments on test-benches are being investigated based on the Material Testing Department.
The work was aimed at identifying solid solutions based on uranium and zirconium dioxides in the phase composition of corium, obtained at different temperatures at the VCG-135 test-bench. One of the main issues is to develop a method for describing solid solutions as components of phase composition.
The article provides a method and results of determining the density, studies of the structural and phase properties of corium samples using scanning electron microscopy (VEGA 3 LMH, TESCAN) and diffractometry (Empyrean, PANalytical).
This paper considers the method of carbidization of tungsten surface with the use of beam-plasma discharge, which was carried out in plasma-beam installation to identify the characteristics of the carbide approach. A distinctive feature of the implemented method is that it is closest to the processes that can cause surface carbidization during the operation of thermonuclear installations. This method allows you to change the parameters of the experiment to obtain a specific coating with specified characteristics. As a result of experimental work, it was found that tungsten semi-carbide W2C is formed at a retention time of 600 s at 1500 °C, and tungsten monocarbide WC at 3600 s.
The article presents a method for calculating the power of the elements of an experimental device, the main purpose of which is to convert the thermal neutron flux of the IGR. This technique is an improvement of various calculation methods for obtaining data on energy release in structural elements of tested devices at the stage of planning experimental studies.
The article addresses computational research on the decision of multi-criterial problem of how to optimize sodium heat exchanger. A heat exchanger under consideration is one of the elements of sodium loop (SL) being designed to provide sodium circulation in the IGR reactor experiments with fast reactor core elements.
The research covered mathematical calculation to select geometry for heat exchanger and identify required coolant flow rate. In ANSYS FLUENT software system, heat exchanger 3D model was developed using chosen geometry and stationary thermal calculation was conducted. Distribution of heat exchanger temperature field with the coolants was received in 3D calculation.
Computational research resulted in receiving best range of heat-exchanger parameters, creating 3D computational model and providing distribution of temperature field for optimized model.
The paper presents the results of mechanical tests to determine changes in the strength characteristics of the material of zirconium alloy E125 after local thermal exposure. Dependences of the strength characteristics of the material of the E125 alloy on the hardness are determined. The maximum and minimum values of strength in the zones of reflow and heat exposure have been determined. An assessment of the change in the geometric parameters and the hardness of the heat- affected spot from the modes of arc action and the conditions of subsequent cooling is carried out.
The article presents the technological cycle of manufacturing the outer casing of an immovable ampoule NA-228 of the Pulsed Graphite Reactor (IGR) made of stainless steel 12X18H10T. The results of strength analysis of structural elements and casing manufacturing technology are presented. By welding control samples, the optimal welding parameters of the casing segments were determined, as well as the number of tacks and layers, order and number of passes ensuring high product quality.
This work is devoted to the determination of impurities in concrete samples – the structural material of the ITER reactor. The results of reactor experiments and spectrometric studies are presented. Irradiation of samples for instrumental neutron activation analysis was carried out at the IVG.1M reactor. Post-analysis included gamma spectrometric measurements with different exposure times of samples from one day to one month, with the calculation of the concentration of the main and impurity elements by the relative INAA method. For comparison, rocks such as SG-4 and SGD were used as standard
materials. An analysis of errors was performed during instrumental neutron activation analysis at the IVG.1M reactor. As a result of the research, the content of elements that can make the main contribution to the radiation situation in the premises during the operation and decommissioning of ITER are determined.
In this work, studies have been carried out on the synthesis of coatings based on hafnium and carbon, using the method of ion-plasma spraying of coatings from alternating layers of hafnium and carbon with a thickness of each layer less than 1 nm. When performing the work, we used a four-channel magnetron setup. In which two oppositely located magnetrons were used. One magnetron is charged with a hafnium target, and the other magnetron is charged with a carbon target. The rate and optimal modes of sputtering of hafnium and carbon have been determined. The dependences of the amount of atomized hafnium and carbon on the power applied to the magnetron are obtained. The average atomization power of hafnium has been determined, which corresponds to the removal of the substance with the removal of carbon at its maximum possible atomization power. The synthesis of hafnium-carbon coatings in the concentration range from 59.8 to 5.3 at.%. Carbon was carried out, and X-ray studies of carbide coatings were performed. Determined in the hafnium-carbon system formed by magnetron deposition, at concentrations from 59.8 to 26.1 at. % carbon in the coating, the cubic phase of hafnium carbide is formed, with a decrease in the lattice parameter. At a concentration of 16.2 at. % carbon, along with the cubic phase of hafnium carbide, hafnium with a hexagonal structure begins to precipitate in the coating. With a further decrease in the carbon concentration in the coating, the hexagonal phase of hafnium becomes predominant.
The article gave a characteristic of used materials; outline of issues of hardware support and methods for mapping the anomalous geomagnetic, gravitational, geothermal fields of various and the interpretation results from the data obtained, the research of linking the observed magnetic fields to separate isolated areas, registered the normal of magnetic field of the Earth. The main regularities of the distribution of the anomalous geomagnetic field (ΔТа) within the Central Kazakhstan, issues of nature of anomalous of the geomagnetic, gravitational, thermal fields in some regions, some large geological structures, of anomalous fields and anomalies. The results of investigations on revealing correlations between anomalous geomagnetic, gravitational, thermal fields and seismicity in the territory of Central Kazakhstan are analyzed.
The article is devoted to improving the safety of experiments carried out at the IGR reactor. The results of calculations of the neutron-physical parameters of experimental devices with a heat-resistant jacket are presented. The use of the casing is intended for additional protection of the IGR reactor core from the possible impact of the melt of the materials of the experimental device. Tungsten, tantalum and carbon fiber reinforced plastic were considered as the material of the protective cover. The use of a protective casing was evaluated according to the following parameters: the effect on the relative power of the experimental device, the effect on the power distribution in the experimental device, the melting temperature and radiation heating of the casing material.
ISSN 1729-7885 (Online)
