Relevance
This Program is aimed at solving the urgent problem of providing experimental research at the Kazakhstani materials testing tokamak (KTM) and testing candidate materials for the first wall of future thermonuclear reactors.
The Kazakhstani Thermonuclear Materials Testing (KTM) Tokamak is the unique tokamak in the world designed for testing structural and functional materials under conditions and thermal load parameters corresponding to their operation in a thermonuclear power reactor (TPR). The creation and commissioning of the KTM tokamak allowed Kazakhstan to enter the extremely limited club of countries capable of conducting advanced research in the field of controlled thermonuclear fusion (CTF), the most promising and safe energy technology of the future.
The implementation of the Program will allow Kazakhstan to become one of the most technologically developed countries in the world, possessing and developing controlled thermonuclear fusion - the most promising and safe energy technology.
Within the framework of the Program, it is planned to conduct scientific research in the following areas:
As part of the first topic of the Program, it is planned to study the plasma discharge of the KTM tokamak in modes with ohmic and RHF heating of the plasma, as well as to develop a project for diagnosing Thomson scattering for the KTM tokamak.
Based on the research results, experimental data on a plasma discharge on a KTM tokamak with a divertor configuration in modes with ohmic and additional high-frequency heating will be obtained, a technical project for Thomson scattering diagnostics (TSD) will also be developed to measure the temperature and electron density in the KTM tokamak plasma and data will be obtained on setting up and testing Thomson scattering diagnostics in laboratory conditions.
As part of the second topic of the Program, it is planned to develop and test new technologies and materials for the KTM tokamak and future thermonuclear fusion reactors.
Based on the research results, experimental data from bench tests of promising materials for thermonuclear technology will be obtained, as well as test data on a plasma replenishment and quenching system based on a gas-dynamic source of a molecular beam, as well as a pulsed plasma accelerator.
As part of the third topic of the Program, work will be carried out to study the KTM tokamak plasma control system, as well as to study the operating modes of the additional RF heating system when introducing power into the KTM tokamak plasma.
Based on the research results, the operation of the plasma control system will be optimized and the optimal and most efficient operating modes of the additional RF heating system when introducing power into the plasma of the KTM tokamak will be determined.
The implementation of the Program will make it possible to achieve the indicators defined in the Concept for the development of the fuel and energy complex of the Republic of Kazakhstan until 2030, the State Program for the Development of Education and Science of the Republic of Kazakhstan for 2020-2025 and other strategic programs in the field of nuclear energy. Moreover, the implementation of the Program will contribute to the achievement of the goalsas well as lanned target indicators defined in the Strategic Plan of the Ministry of Energy of the Republic of Kazakhstan.
The results obtained during the Program will be interesting to foreign investors from non-CIS countries: France, Great Britain, USA, Italy, Spain, Germany, Japan, South Korea and China and will allow them to be attracted for the subsequent implementation of a joint program of work to test technologies and methods and materials for future fusion reactors.
Within the framework of the Program, it is planned to conduct a set of studies aimed at bringing the KTM installation to its nominal parameters, as well as conducting materials science studies of promising materials for the first wall of thermonuclear reactors, and developing controlled thermonuclear fusion technologies. In the course of research work, modern methods of high-temperature plasma diagnostics, materials research, such as scanning and transmission electron microscopy, X-ray structural and X-ray phase analysis, and a complex for studying the physical and mechanical properties of materials will be used. To study the plasma-wall interaction and the interaction of hydrogen isotopes with materials, methods of permeability, thermal desorption spectroscopy, differential scanning calorimetry, mass-spectrometric analysis, and so on will be used.
The results of the research will be published in peer-reviewed scientific journals and presented at international conferences. In addition, some research results will be presented in the form of patents or finished scientific and technical products.
Purpose of the Program:
Methodological and technical support for the operation of the KTM tokamak and conducting research into plasma physics and comprehensive testing of candidate structural materials for a fusion reactor.
Expected Outcomes
Direct results:
Topic 01. Development of methods for conducting research on KTMs and means of monitoring the physical parameters of high-temperature KTM plasma in the process of its interaction with materials:
Topic 02. Development and testing of new technologies and materials for the KTM tokamak and future fusion reactors:
Topic 03. Development, adjustment and optimization of operating modes of KTM tokamak systems to ensure the conduct of experiments:
Final Result:
- In 2024, experimental data will be obtained on plasma discharge with a divertor configuration in the ohmic heating regime, a conceptual design of Thomson scattering diagnostics for the KTM tokamak will be developed, experimental data on the operating regimes of the gas-dynamic injector (GDI) for plasma fueling on the KTM tokamak will be acquired, enabling determination of the optimal GDI position relative to the plasma column, optimal electromagnetic valve opening duration, and optimal gas pressure in the GDI supply line, a design of a movable divertor segment module based on a lithium capillary-porous system (CPS) will be developed along with the principal scheme of control and management systems for its operating regimes intended for KTM operation, a methodology for sequential plasma irradiation of tungsten with inert gases and deuterium will be developed with subsequent acquisition of experimental results and microstructural studies of the surface of the irradiated tungsten samples, results of comparative studies on the structure and physico-mechanical properties of austenitic steels with varying nickel content in the unirradiated state as well as samples prepared for neutron and ion irradiation will be obtained, experimental data on the efficiency of the plasma control system (PCS) in the ohmic heating regime will be acquired, and an equivalent plasma load will be developed.
- In 2025, experimental data will be obtained on the operating parameter domain of the KTM tokamak, a detailed working design of the Thomson scattering diagnostics (TSD) for the KTM tokamak will be developed, experimental data will be acquired on the optimization of gas-dynamic injector (GDI) operating regimes using the determined optimal parameters (distance from the nozzle to the edge plasma, gas pulse duration, and gas supply pressure upstream of the nozzle) for plasma fueling and termination, followed by analysis of the obtained experimental results, a movable divertor segment module for KTM equipped with control and management systems for its operating regimes data acquision module (DAM) will be fabricated, methodological recommendations will be developed for conducting tests of the movable divertor segment module under bench conditions, data will be obtained on gas release dependence from tungsten samples sequentially irradiated with argon and deuterium, along with microstructural studies of tungsten samples after plasma irradiation, neutron-irradiated samples of austenitic steels will be produced and comparative studies of the structure and physico-mechanical properties of austenitic steels with varying nickel content after neutron irradiation will be performed, technical proposals will be elaborated to enhance the efficiency of the plasma control system (PCS), and experimental data will be obtained on the commissioning regimes of the KTM tokamak RF system, including synchronous startup and stable operation of the generator connected to the equivalent plasma load.
- In 2026, experimental data will be obtained on plasma discharge regimes of the KTM tokamak with ohmic and additional high-frequency heating, experimental data will be acquired on the influence of additional RF heating on the plasma discharge, a detailed technical design of the Thomson scattering diagnostics (TSD) for measuring electron temperature and density in the KTM tokamak plasma will be developed, data on the setup and laboratory testing of the diagnostics and its components will be obtained, test results will be acquired for the developed plasma fueling and termination system based on the gas-dynamic injector of molecular beam as well as the plasma density control system based on the impulse plasma accelerator (IPA), a conclusion will be drawn regarding the optimal feasibility of using the gas-dynamic injector of molecular gas flow for plasma fueling and termination on the KTM tokamak along with the selection and justification of the IPA design and its main technical characteristics, a movable divertor segment module for KTM based on a lithium capillary-porous system will be fabricated and test results of the data acquisition module (DAM) under bench conditions will be obtained, recommendations will be elaborated for selecting the optimal operating regimes of the DAM thermal stabilization system during experiments on KTM, experimental data will be obtained on hydrogen isotope interaction processes under sequential irradiation of tungsten samples with a mixture of inert gases, low-energy deuterium plasma, and mixed hydrogen-helium (H + 10% He) plasma, parameters of deuterium release and retention in tungsten samples will be determined, microstructural studies of the surface morphology of plasma-irradiated tungsten samples will be performed, data on gas release dependence from tungsten samples sequentially irradiated with helium and deuterium will be obtained, experimental data will be acquired on the effects of neutron and ion irradiation on the structure and properties of austenitic steels used as structural materials for KTM, ion-irradiated samples of austenitic steels with varying nickel content will be produced, changes in the structure and properties of steels with different nickel contents resulting from ion irradiation will be identified, data from studies of the KTM tokamak plasma control system will be obtained with the aim of optimizing regulators for plasma current, shape, and position control, experimental data on the performance of the optimized plasma control system will be acquired, and the optimal and most efficient operating regimes of the additional RF heating system for power input into the KTM tokamak plasma will be determined along with experimental data on the operation of the RF generator of the additional plasma heating system during power input into the plasma.
Over the course of the entire program, publications will be prepared and published:
– at least 4 (four) articles and/or reviews in peer-reviewed scientific publications in the scientific area of the program, included in the 1st (first), 2nd (second) or 3rd (third) quartiles in the Web of Science database and (or) having a percentile in Cite Score in the Scopus database is at least 40 (forty);
– or at least 3 (three) articles and/or reviews in peer-reviewed scientific publications included in the 1st (first), 2nd (second) or 3rd (third) quartiles in the Web of Science database and (or) having a percentile according to Cite Score in the Scopus database has at least 40 (forty), and at least 1 (one) foreign or international patent included in the Derwent Innovation – Clarivate Analytics database;
– as well as at least 5 (five) articles in a peer-reviewed foreign and (or) domestic publication with a non-zero impact factor (recommended by Committee for Quality Assurance in the Field of Science and Higher Education of the Ministry of Science and Higher Education of the Republic of Kazakhstan (CAQSHE));
– at least 2 (two) patents for an invention (certificate of copyright) or 3 applications for an invention filed with the RSE “NIIS”.
R&D Main Results
In 2024, as part of the Implementation of the Program “Scientific and Technical Support for Experimental Research on the Kazakhstan Materials Science Tokamak KTM”, the following key results were achieved:
1) The experimental data on the plasma discharge in the divertor configuration at the KTM tokamak is obtained. The stable discharge parameters in the divertor configuration and with an elongation of k≈1.7 are achieved for the first time. The discharges starting from 25 kA in central solenoid is obtained for the first time, which allowed to use the entire supply of the conductive flux in the inductor. These results will optimize the plasma parameters and further obtaining discharges with nominal parameters.
2) During the development of the Thomson scattering diagnostics, the plasma probing and collecting the scattered laser radiation schemes have been proposed, which take into account the design features of the KTM tokamak. Preliminary estimates of the developed conceptual design of the Thomson scattering diagnostics for the KTM tokamak show that the spectral devices with parameters close to those used at the Globus-M2 tokamaks can be used to measure the temperature and density spatial distributions.
3) Tests were carried out on a KTM tokamak at the pressures of 10, 20 and 40 bar in order to stabilize the plasma density in the future. The obtained experimental data on operation modes of GDS have shown that a change in the duration of the control pulse of less than 20 ms does not lead to a proportional change in the gas flow, which requires further optimization of the valve. In 2025, it is planned to replace the solenoid valve with a piezoelectric one to improve the accuracy of gas flow control.
4) As part of the tests of the KTM tokamak divertor elements with lithium CPSs, a number of key developments were carried out, namely the design of the mobile module of the segment of the diverter based on lithium CPS and the principle scheme of the monitoring and control systems of the working modes of the module for its operation on the KTM. Based on the research results, the optimal shape of the divertor segment module (DSM) was chosen – conical one, which allows effective varying the heat flow amount. The module basic geometric parameters have been determined, which ensures its stable operation under the high thermal loads. The design of a mobile module based on a molybdenum mesh filled with liquid metal (lithium or its alloys) was also chosen, which will increase the resistance of the divertor elements to plasma effects. Additionally, an analysis of the vacuum motion control systems has been carried out, which will ensure the effective control of the module under the tokamak operating conditions.
5) The results of experimental works has been obtained on the irradiation of the tungsten samples with the deuterium plasma at various potentials, which showed that the plasma concentration is higher at lower voltage values, which is confirmed by probe diagnostics and optical emission spectroscopy. According to the results of the microstructural studies of the surface of irradiated tungsten samples, it was found that the irradiation of tungsten with the argon plasma led to a decrease in the formation of blisters, while the helium plasma, on the contrary, contributed to their increase. At the same time, no characteristic tungsten “fluff” was observed after the helium irradiation, but a wavy structure was recorded. Based on the results of theoretical and experimental work, a method for the sequential plasma irradiation of tungsten with inert gases and deuterium was developed and implemented.
6) The results of investigations of structure and physical and mechanical properties of austenitic steels with different nickel content - 12Cr18Ni10Тi steel (KMT material), and AISI 304 and AISI 316 steels have been obtained. It is revealed that as a result of cold deformation by rolling in the microstructure of austenitic grains fragmentation and strong defect distortions occur: texture, complex sub-grain structure, dislocation nets, formation of deformation twins. Changes in the phase composition of steel due to the formation of deformation martensite were observed. The austenitization of the investigated materials was carried out and the resulting structure was studied. It was found that heat treatment of AISI 304 and 12Cr18Ni10Ti steels resulted in almost 100% austenitic structure with zero ferrite content, which was confirmed by magnetometry measurements. The grain size was ~45-50 µm. Nanoscale inclusions were observed in the body and along the grain boundaries. Taking into account the results obtained, 180 samples of steels pre-austenitized under vacuum conditions were prepared for neutron and ion irradiation in 2025-26. Mechanical tests of AISI 304 and 12Cr18Ni10T steels at room temperature showed that AISI 304 steel, characterized by a reduced (up to 8%) nickel content, has the highest ductility. TEM studies of the microstructure after deformation showed that the martensitic α' phase in the samples nucleates at the intersection of shear bands.
7) As a result of the carried out experiments on the effectiveness of PCS in the Homic heating mode, it was found that the PF1 and PF4 coils have significantly greater efficiency in controlling the plasma vertical position compared to the HFC coil, although the HFC provides a sufficient controllability area to prevent the vertical displacements (VDE). The KTM tokamak poloidal system allows effective controlling the plasma position at the current of up to 750 kA and elongation up to 1.7. However, the detected failures in discharges with elongation equal to 1.6 may be due to the inefficiency of the existing control system or errors in discharge scenarios. Possible causes include poor regulator settings or errors in diagnosing the plasma vertical position.
8) As a result of the calculations, two optimal design options have been selected for the plasma load equivalent: a resonator with a single steel tank and a resonator with a water salt absorber in a dielectric container with an external steel shield. The optimal shape of the absorber was determined by the shape of a parallelepiped with a contour repeating the antenna module. For the large PLE, the design has been developed that ensures maximum absorption of the HF power (up to 99%) and high quality factor, which allows the self-oscillating generator to work steadily. A small PLE with an impedance close to the plasma impedance is designed to work out the antenna module matching, although it is less effective in absorbing the plasma wave.
The program research group includes 2 doctors of Sciences, 9 PhDs, 3 PhD candidates, 8 postgraduates and doctoral students, 10 masters, 1 undergraduate. The number of the young scientists and specialists (up to 35 years old) is 25 people.
Based on the results of the work, 15 publications were published in 2024, including 8 scientific articles.
In 2025, as part of the Implementation of the Program “Scientific and Technical Support for Experimental Research on the Kazakhstan Materials Science Tokamak KTM”, the following key results were achieved:
1) Discharge scenarios for a divertor configuration with the tokamak's nominal parameters were calculated. The operational parameter space of the KTM tokamak was analyzed, and its diagnostic complex was prepared and configured. Plasma discharges with a plasma current of Ipl = 750 kA were achieved in ohmic heating mode with a divertor configuration and an elongation of k = 1.7–1.8. Analysis of the experimental data established that increasing the plasma current beyond 500 kA leads to plasma disruptions, which limit the current amplitude to approximately 700 kA and restrict the discharge duration at this current level. Achieving plasma currents exceeding 750 kA in ohmic heating mode under the present conditions and with the current first-wall materials presents significant difficulties. The character of the discharges is primarily influenced by impurities entering the plasma from the wall. These results will be used in subsequent work to improve and optimize plasma discharges, with the goal of mitigating or eliminating plasma disruptions.
2) A working design for a Thomson scattering diagnostic has been developed. The design includes calculations of the optical elements and specifies the components required for its implementation on the KTM tokamak. This system will subsequently enable the creation of a diagnostic for measuring plasma electron temperature and density, which are essential for research on the KTM tokamak.
3) The gas-dynamic injection (GDI) system of the KTM tokamak has been upgraded to mitigate the influence of the coil magnetic field on the electromagnetic gas puff valve. Experimental studies involved varying key parameters—such as the nozzle-to-sensor distance, gas pressure upstream of the valve, and the control pulse duration—yielding data on system behavior. It was established that the peak value of the pulsed pressure is determined primarily by the nozzle-to-plasma distance, while the valve opening duration affects only the total volume of injected gas. An exponential dependence of pressure on distance was obtained, enabling more accurate forecasting of plasma fueling and disruption mitigation scenarios. A time delay of 15–20 ms between valve actuation and gas arrival in the chamber was recorded and can be incorporated into discharge scenarios via control system programming. The results confirm the operational capability of the upgraded gas-dynamic injection system and provide a foundation for subsequent experiments aimed at optimizing gas injection regimes during plasma discharges in the KTM tokamak.
4) Design documentation for a movable divertor segment module (DSM) based on lithium capillary-porous systems (CPS) has been developed and released. All major components and assemblies of the DSM have been manufactured and verified for compliance. The movable module has been successfully assembled and is ready for bench testing. Thermophysical analysis has been performed, confirming the structure's thermal resilience under heat loads of up to 20 MW/m². Methodological guidelines for conducting bench tests of the movable DSM have been developed.
The obtained results confirm the fundamental feasibility and practical viability of employing a movable divertor module with a lithium CPS in the KTM tokamak. The design is ready for the bench testing phase.
5) Data on the gas release from tungsten samples sequentially irradiated with argon and deuterium were obtained. Analysis established that the gas release occurs predominantly in the form of HD molecules. For samples W1 and W2 (without pre-exposure to argon plasma), deuterium release is characterized by bulk diffusion at 750–820 °C with an activation energy of approximately 267 kJ/mol, reflecting the dominance of deep retention mechanisms. In the samples pre-exposed to argon plasma (W3 and W4), two types of traps were identified: surface traps with a low-temperature desorption peak (~400 °C, Ea ~166 kJ/mol) and bulk traps with a high-temperature desorption peak (~800 °C, Ea ~270 kJ/mol). This indicates that Ar⁺ irradiation enhances the retention of weakly bound deuterium on the surface but does not prevent its penetration and trapping in the bulk material. The results of subsequent microstructural investigations support these findings. It was determined that the tungsten surface develops an "etching relief" after argon plasma irradiation, characterized by randomly distributed protrusions and depressions of various shapes, as well as a significant number of pores of different sizes. Following sequential irradiation with argon and deuterium plasma, a similar surface morphology is observed, with the characteristic formation and growth of bubbles.
6) Samples of austenitic steels—12Kh18N10T (the KTM tokamak structural material) and AISI 304—neutron-irradiated in the VVR-K reactor to a maximum fluence of 5.8 × 10²³ n/cm² (>0.1 MeV) were obtained. The results of investigations into the microstructure and physico-mechanical properties of these two steels with different nickel content after neutron irradiation are presented. The irradiation dose was calculated in units of displacements per atom (dpa), with the maximum fluence determined to be ~0.078 dpa. Transmission Electron Microscopy (TEM, JEOL JEM 2100) revealed that short-term irradiation in the VVR-K reactor produced radiation-induced clusters ranging in size from 2 nm to 6 nm, which significantly impact the material's ductility. Scanning Electron Microscopy (SEM) indicated that neutron irradiation causes a minor (~10%) reduction in grain size. Mechanical tests demonstrated an increase in the strength of the irradiated steels. The yield strength increased more significantly (~2.5 times) than the ultimate tensile strength, leading to a reduction in the material's capacity for strain hardening and uniform elongation. The limiting neutron irradiation dose at which uniform elongation approaches zero was calculated to be 0.3 dpa for steel 12Kh18N10T and 0.9 dpa for steel AISI 304. The microhardness corresponding to necking formation was 250–300 HV for steel 12Kh18N10T and 310–325 HV for AISI 304. These values correspond to a necking strength of 1000 MPa and 1300 MPa, respectively. The relationship between microhardness and true stress in deformed, non-irradiated, and irradiated AISI 304 samples conforms to the linear dependence established for steel 12Kh18N10T.
7) The performance of the plasma control system (PCS) was evaluated based on experimental data from ohmic plasma discharges. The influence of actuator characteristics on the PCS effectiveness was assessed, leading to the following proposals for enhancing the performance of its components and algorithms: Implementation of a two-tier plasma vertical position control algorithm: Fast corrections are performed by the HFC (Horizontal Field Coil) windings, while the "slow" circuit of poloidal field coils is engaged once the vertical velocity is reduced. This approach will redistribute the load and increase the system's operational lifetime. Reduction of control loop delays: the control cycle is to be decreased from 4 ms to 1.5 ms by migrating the plasma position regulation functions from the central control unit to a dedicated real-time computer. Increase of the inverter buffer capacitor operating voltage: the bus voltage for the HFC power supply inverter will be raised from 1000 V to 1400 V, aligning it with the nominal parameters of the IGBT modules and the energy dump system.
8) Experimental data were obtained during the testing of the KTM tokamak's high-frequency (HF) system, focusing on synchronous startup and stable operation of the generator connected to a plasma load equivalent. It was established that stable operation of the HF generator is achievable in the designed push-pull mode at a generation frequency of 13 MHz. The investigations were conducted at a reduced anode voltage and with a pulse duration not exceeding 5 seconds. These parameters were selected to minimize heating of the solution within the plasma load equivalent. Oscillograms of the generator's operation into the plasma load equivalent were obtained. The test results confirmed the operational capability of the two-tube HF generator in the push-pull (combined) mode at the reduced anode voltage, demonstrating a stable generation frequency of 13 MHz.
The research team for this program comprises 2 full professors (D.Sc), 1 associate professor, 10 PhD holders, 2 candidates of science, and 7 postgraduate researchers (including PhD students) and further supported by 13 research assistants with MSc degrees. Includes in total of 24 early-carrer youth scientists and specialists (under 35 y.o.).
Based on the results for 2025, overall 14 publications which consists 8 scientific papers were produced.