How fusion energy is created
Fusion is the process that provides energy to the Sun and other stars. During the reaction, light atomic nuclei combine into a heavier nucleus, and part of their mass is converted into energy.
On Earth, the reaction between two isotopes of hydrogen — deuterium and tritium — is considered the most promising. During their fusion, a helium nucleus and a fast neutron are formed. About 80% of the energy released is absorbed by the neutron, which then has to heat the shell surrounding the reactor. The resulting heat is planned to be used to produce steam and rotate a conventional turbine, as in a thermal or nuclear power plant.
To start the reaction, the fuel must be transformed into plasma and heated to approximately 150 million degrees Celsius — approximately ten times higher than the temperature in the center of the Sun. On the Sun, the compression of matter is helped by enormous gravity. In the terrestrial installation, it has to be replaced by a magnetic field or an ultra-powerful laser pulse.
For stable synthesis, three conditions must be fulfilled at the same time: to reach a high temperature, to create a sufficient density of particles and to hold the plasma for a long enough time. It is the combination of these parameters, and not a single temperature record, that determines the actual progress of the installation.
Two main approaches are used today.
With magnetic confinement, the plasma is inside a ring-shaped vacuum chamber. Powerful superconducting magnets prevent it from touching the walls. The most common installation of this type is a tokamak. An alternative is the stellarator, which has a more complex magnetic field shape, but is potentially better suited for continuous operation.
During inertial fusion, a small capsule with fuel is simultaneously irradiated with lasers. The outer layer of the capsule evaporates, the fuel is sharply compressed and briefly reaches the conditions under which the fusion reaction begins.
China built the largest superconducting magnet
In June 2026, the Institute of Plasma Physics of the Chinese Academy of Sciences announced the successful completion of tests of a D-shaped toroidal field magnet for future fusion reactors.
Its length is 21 meter, width - 12 meters, height - 3.3 meters, weight - 582 tons. According to the developers, the volume of the magnet is 1.3 times greater than the volume of a similar element of the international ITER reactor, and the accumulated magnetic energy is three times greater.
Toroidal magnets form the main field around the vacuum chamber of the tokamak. The stronger and more stable the field, the higher the pressure and temperature of the plasma that can potentially be maintained inside the device.
The creation of such a magnet means that China has mastered the production of large-sized superconducting coils, special steel, low-temperature insulation, protection systems and ultra-low resistance connections. However, a single magnet is not a reactor by itself. The power plant will require a full set of coils, a vacuum chamber, a cryogenic system, plasma heating, neutron shielding and tritium reproduction equipment.
China is simultaneously developing several interconnected projects. The EAST tokamak in January 2025 held the plasma in high-hold mode for 1.066 thousand seconds, significantly exceeding the previous result of 403 seconds. The experiment was conducted without industrial energy production, but demonstrated the possibility of long-term operation of the superconducting tokamak.
The next stage should be the BEST installation, the construction of which is underway in Hefei. It is planned to be completed by the end of 2027. Unlike EAST, BEST is designed for deuterium-tritium burning plasma experiments and should receive 20 to 200 MW of fusion power. Chinese developers expect to demonstrate a positive energy balance and the ability to produce electricity by around 2030. So far, these are the stated goals of the project, which must be confirmed by experiments.
US has achieved repeatable laser ignition
The main US government achievement remains the work of the NIF National Laser Fusion Reactor Complex at Lawrence Livermore National Laboratory.
In December 2022, NIF for the first time received more energy from a fusion reaction than the lasers directly delivered to the fuel target. After this ignition was repeated several times.
In an experiment in April 2025, lasers delivered 2.08 megajoules to the capsule, and the reaction produced a record 8.6 megajoules of thermonuclear energy. The gain factor at the level of the target exceeded four, and the experiment itself became the eighth successful ignition at NIF. The results were presented in detail by the laboratory in April 2026.
However, this does not mean that NIF has become a power plant with a positive energy balance. To power the laser complex, much more electricity is needed than the fuel capsule reaches. In addition, the NIF produces single pulses and was created primarily for scientific and defense research, while an industrial plant would need to repeat shots many times per second, cheaply produce high-precision capsules and efficiently convert heat to electricity.
At the same time, the private sector is developing in the US. The Department of Energy reported that aggregate private investment in U.S. fusion projects exceeded $10 billion. Approved on June 9, 2026, the state road map provides support for experimental facilities and an attempt to bring commercial fusion generation to market in the mid-2030s. At the same time, the agency acknowledges that the implementation of the program depends on future funding and government partnerships.
Commonwealth Fusion Systems is building a compact SPARC tokamak in Massachusetts with magnets made of high-temperature superconductors. In April 2026, the company estimated that the project was about 75% ready. SPARC will not be a full-fledged power plant: its task is to show that the energy of reactions inside the plasma can exceed the energy spent directly on its heating.
Another American developer, Helion, uses a pulsed magnetic system with direct conversion of plasma expansion into electricity. In February 2026, the company announced that its Polaris facility had reacted with deuterium and tritium and heated the plasma to 150 million degrees. These indicators are published by the company itself and are not yet equivalent to demonstrations of a positive balance of the entire installation.
In June, Helion received licenses in the state of Washington for the use of radioactive materials and emissions for the Orion complex under construction. The regulatory approval allows the construction of the facility to continue, but does not confirm that the stated energy characteristics of the future installation have already been achieved.
ITER assembles the largest international tokamak
The international ITER reactor is being built in the south of France with the participation of the European Union, China, India, Japan, South Korea, Russia and the USA.
ITER should produce 500 MW of thermonuclear power in plasma with external heating of 50 MW, i.e. reach a factor of Q=10. At the same time, the installation will not supply electricity to the network. Its task is to demonstrate the stable operation of a burning deuterium-tritium plasma and to test the technologies necessary for subsequent demonstration power plants.
In June 2026, the assembly of the central solenoid consisting of six modules was completed at the site. In July, the sixth sector of the vacuum chamber was installed in the tokamak shaft, after which about two-thirds of the future reactor ring was assembled.
The project is far behind the original schedule. According to the updated plan, research operation should begin in 2034, operation at full magnetic power in 2036, and the first deuterium-tritium experiments in 2039.
ITER's delays demonstrate the scale of the engineering complexity. Even with international funding, the manufacture of unique magnets, vacuum modules and cooling systems takes decades.
Russia, despite war and sanctions, maintains access to ITER
The Soviet Union played a significant role in the initial stage of controlled fusion research. The first tokamak was created at the Kurchatov Institute in 1954, and later the term itself appeared, formed from the phrase "toroidal chamber with magnetic coils".
The main active Russian experimental installation in this field is the T-15MD tokamak, put into operation in 2021. On it, stable modes of plasma containment, its interaction with the reactor walls, diverter operation, additional heating and control of the plasma cord are investigated. The obtained results are expected to be used during the development of a thermonuclear source of neutrons and a hybrid reactor that combines fusion and fission technologies.
Thus, the Russian program is not focused on building its own thermonuclear power plant, but on conducting physical experiments, preserving its own scientific competences, developing reactor technologies and creating hybrid installations. At the same time, the operation of the T-15MD allows the Russians to participate in research related to the International Experimental Thermonuclear Reactor ITER.
Russia, despite the sanctions, remains one of the seven members of ITER. Its share in the pre-agreed construction cost is about 9.1%. A significant part of the contribution is provided in kind — in the form of equipment and technologies. Russian organizations participate in the supply of superconducting conductors, elements of a vacuum chamber and divertor, gyrotrons for heating plasma, diagnostic components and equipment for power supply systems.
After the start of a full-scale war between Russia and Ukraine, the question of Moscow's further participation in the international project acquired not only a political, but also an ethical and security dimension. However, the current ITER agreement does not provide for a mechanism to forcibly exclude a participant or suspend his rights. It allows only the voluntary withdrawal of the state from the project, the European Commission noted. At the same time, Russia did not serve as the rotating chairman of the ITER Council for two years, and bilateral contacts with it, according to Brussels, were minimized. The European Commission also claimed that further development and operation of the reactor would not depend on Russian intellectual property rights. In this situation, it is expedient for Ukraine, within the limits of the current EU sanctions mechanisms, to strengthen the monitoring and audit of deliveries involving sanctioned organizations from the Russian Federation.
Germany is testing an alternative to tokamaks
Germany is developing the world's largest Wendelstein 7-X stellarator. Unlike a tokamak, a stellarator creates the required magnetic field shape primarily with external coils and does not depend on the strong electric current inside the plasma.
This makes the magnets more difficult to manufacture, but potentially allows the facility to operate continuously and reduces the risk of some types of plasma disruptions.
In May 2025, Wendelstein 7-X set a record for the triple product—a combination of temperature, density, and retention time—for long pulses lasting more than 30 seconds. In one of the experiments, the high rate was maintained for about 43 seconds.
After the modernization, the installation should resume experiments in August 2026. Germany has also begun development of 2 MW gyrotrons for more efficient microwave heating of plasma.
Great Britain prepares STEP prototype
Great Britain, after completing experiments on the European JET tokamak, focused on the national STEP program.
The spherical tokamak prototype is planned to be built on the site of the former West Burton coal-fired power station. The project should combine plasma, magnets, tritium production, heat removal, equipment maintenance and power generation in one facility.
In April 2026, the UK Atomic Energy Authority presented a roadmap for 2026-2030. At this stage, the country forms industrial cooperation, develops reactor materials and selects partners for the implementation of STEP. Before the actual production of electricity, the project still needs to go through design, licensing and construction.
Japan and the European Union are preparing a new stage of JT-60SA
Japan, together with the European Union, operates the JT-60SA, which is officially recognized as the largest operating tokamak. The installation should help develop operating modes for ITER and future demonstration reactors.
After the first stage of experiments, the tokamak was upgraded by installing new heating systems, diagnostics and divertor elements. The second experimental phase of OP2 began in April 2026.
The JT-60SA will not use deuterium-tritium fuel and is not designed to generate electricity. Its main task is to learn how to form a stable plasma with the parameters necessary for future reactors.
South Korea focuses on long-lasting plasma and tungsten walls
South Korea's KSTAR tokamak is used to study long-term high-temperature regimes and control plasma instabilities.
Korea is gradually replacing the carbon elements of the inner surface of the installation with tungsten ones. Tungsten is considered as one of the main materials for the divertors of future reactors, as it can withstand high temperatures, but its entry into the plasma can drastically worsen its parameters.
In 2025, the Korean Institute of Thermonuclear Energy agreed with the French CEA center on joint experiments on the KSTAR and WEST tokamaks precisely in the conditions of tungsten walls. This direction should help solve one of the main problems of future power plants — the removal of heat and particles from the plasma without destroying the equipment.
Why fusion energy is important
The main advantage of fusion is the huge energy density of the fuel. Deuterium is found in ordinary water, and tritium is supposed to be produced directly in the reactor during the interaction of neutrons with lithium.
According to ITER estimates, a power plant with a capacity of about 1 GW would consume about 250 kg of deuterium and tritium per year, while a coal-fired plant of similar capacity would require millions of tons of fuel.
The reaction itself produces no carbon dioxide. The main product is helium. A thermonuclear installation also does not support a self-accelerating chain reaction: in the event of a violation of magnetic containment or fuel supply, the plasma quickly cools and the reaction stops.
The amount of fuel in the chamber at each moment of time is very small, so an accident similar to the acceleration of a conventional nuclear reactor is physically impossible.
At the same time, the statement about completely waste-free thermonuclear energy would be wrong. Fast neutrons activate the chamber materials, so individual metal elements will become radioactive and require special handling. However, developers expect to use materials whose radioactivity declines much faster than some of the waste from traditional fission reactors.
If the technology proves economically viable, fusion plants will be able to provide stable, low-carbon generation regardless of the weather. This would complement solar and wind farms, reduce the use of gas and coal, and generate energy for industry, hydrogen plants, water desalination and large data centers.
What obstacles remain to be overcome
The first challenge remains the energy balance. Researchers distinguish between the energy released inside the plasma or the target and the balance of the entire installation. A positive result at the level of the fuel capsule, as at NIF, does not mean that the laboratory produced more electricity than it consumed.
The future station must provide power for magnets, cryogenic units, pumps, heaters, lasers, purification systems and fuel production. After that, it is still necessary to convert the received heat into electricity and leave a sufficient volume for sale to the network.
The second obstacle is the duration of operation. Many installations are capable of producing very hot plasma for seconds or minutes, but the power plant must operate for months with high availability and minimal interruptions.
A third problem is neutron damage to materials. The neutrons of a thermonuclear reaction knock atoms out of the crystalline structure of metals, making them brittle and causing radioactivity. The divertor, where the heat and waste products of the reaction are directed, is subjected to particularly high loads.
The fourth task is related to tritium. Its natural reserves are extremely small. The future installation must itself produce no less tritium than it consumes, remove it from the lithium shell and return it to the plasma. ITER will be the first large-scale facility to test various tritium reproduction modules, but a full-fledged closed fuel cycle has not yet been demonstrated anywhere.
The fifth problem is cost. Superconducting materials, cryogenic systems, sophisticated robotics, and neutron-resistant alloys remain expensive. Even a physically viable reactor will not become a mass source of energy if the cost of its construction, repair and fuel turns out to be higher than the alternatives.
When may the first power plant appear
China expects to demonstrate energy production at BEST by around 2030. Several American companies call the beginning of the 2030s. The US Department of Energy is targeting the middle of the next decade. Great Britain and European programs talk about a longer transition to prototypes and industrial reactors.
These terms should be taken with caution. China's BEST, America's SPARC and Polaris, Britain's STEP and the international ITER use different technologies and define success differently. Some must demonstrate a positive balance in the plasma, others must receive an electrical impulse, and others must demonstrate a full cycle of the station's operation.
The main change in recent years has not been the solution of all physical problems, but the transition to an engineering competition. Countries and private companies are already building large magnets, reactor buildings, vacuum chambers and licensing sites.
China's superconducting magnets prove that equipment on the scale of a future reactor can be manufactured. American laser experiments proved the repeatability of ignition at the level of the target. Germany has brought stellarators closer to long-term operation, and ITER combines the technologies of major scientific countries in the largest magnetic confinement facility.
The next decisive stage will come when one of the programs will not just create hot plasma, but at the same time will confirm long-term operation, fuel reproduction, material stability and positive balance of the entire power plant. It is only after this that thermonuclear fusion will be able to move from the category of promising scientific projects to a real energy industry.
Ukraine researches plasma and materials for future reactors
Ukraine also participates in international research on controlled fusion, although its program is much smaller than the Chinese, American or European ones and does not include the construction of its own fusion power plant.
The main Ukrainian center is the Institute of plasma physics of the National Scientific Center "Kharkiv Physical and Technical Institute". He is a member of the EUROfusion European consortium and coordinates the Ukrainian research group, which includes six scientific organizations. About 135 researchers, engineers, technical specialists and graduate students work at the institute.
Ukrainian scientists operate the Uragan-2M and Uragan-3M stellarators. Unlike the more common tokamak, the stellarator traps the plasma with a complex magnetic field and is potentially better suited for long continuous operation. Uragan-2M transmits experimental data to the EUROfusion program.
Another important direction is related to the interaction of hot plasma with the walls of the reactor. The Kharkiv QSPA Kh-50 and QSPA-M installations create powerful plasma flows that simulate short-term extreme loads inside future thermonuclear installations.
QSPA Kh-50 is one of the most powerful installations of this type. With its help, researchers check how tungsten, special alloys and protective coatings withstand plasma disruptions and thermal pulses. Solving this task is of critical importance, since the materials of the reactor's inner chamber must withstand high temperatures and intense neutron irradiation.
Ukraine has been associated with the Euratom research and training program since 2021. Ukrainian organizations can participate in its competitions and projects on the same terms as EU institutions. In the previous Euratom program for 2014-2020, Ukrainian participants received about EUR4.9 million for projects in the field of nuclear fission and fusion.
After the start of full-scale war, EUROfusion allocated EUR2.5 million to support the Kharkiv Institute of Physics and Technology and related Ukrainian organizations. The funds were intended for equipment, preservation of scientific teams and grants to young researchers and engineers.
At the same time, Ukraine is not an independent participant of ITER. The parties to the project are the European Union, China, India, Japan, South Korea, Russia and the USA. Therefore, Ukraine does not have a separate national quota for the supply of equipment and financing of the reactor, as a state that is a party to the agreement.
