ITER, The Way To Nuclear Fusion
ITER, an acronym for International Thermonuclear Experimental Reactor, also standing for “The Way” in Latin, is the world’s largest effort toward mastering nuclear fusion-based energy generation.
ITER is funded and run by seven parties: the European Union (27 countries), China, India, Japan, Russia, South Korea, and the United States. It also has cooperation agreements with Australia, Canada, Kazakhstan and Thailand.
The UK used to be part of the program when it was in the EU and discontinued its participation in 2023.
Source: SciTech Daily
In theory, ITER could be the prototype and experimental demonstrator for commercial fusion, opening mankind to virtually unlimited cheap energy.
This would make tasks like greening deserts, fighting CO2 emissions, or becoming a space-faring civilization almost trivial.
So, while it might take a while to bear fruit, the potential is so colossal that it might be remembered as one of the most important megaprojects ever created.
Nuclear Fusion
Unlimited Power
Nuclear fusion is different from classical nuclear energy (fission) in that it uses very light elements. Instead of splitting heavy atoms like uranium, it merges together very light atoms, generally hydrogen.
This theoretically makes nuclear fusion a source of unlimited power, as hydrogen is the most common form of matter in the Universe.
This process produces massive amounts of energy, resulting in 3-10x more energy than nuclear fission and the energy source powering the stars.
Source: Nature
One gram of deuterium-tritium fuel mixture in the process of nuclear fusion is equivalent to 11 tonnes of coal. Someone’s entire lifetime energy consumption could be covered by little more than a bottle of fuel held in their hand.
Advantages of Nuclear Fusion
Not only does nuclear fusion provide a lot of energy, but it has a few key benefits that no other power source can claim:
- Deuterium is so abundant in the Earth’s oceans and surface waters that it is essentially unlimited and equally accessible to every nation on Earth.
- The nuclear reaction produces no radioactive waste, only chemically harmless helium.
- No CO2 or other environmentally harmful products are created by the reaction either.
- As it produces no enriched uranium, plutonium, or other radioactive materials, nuclear fusion does not carry a risk of nuclear proliferation (nuclear weapon-grade material).
- This would make the adoption of nuclear fusion a neutral technology without the restrictions imposed on fission nuclear technology.
- No risk of meltdown or out-of-control chain reaction. The reaction is actually so difficult to sustain that any failure would immediately lead to the disruption of the plasma and an interruption of the nuclear reaction and energy production.
- If it is self-sustaining and strongly energy-positive, nuclear fusion is expected to be as cheap or cheaper to operate than fission-based nuclear power plants.
- Further technological progress and economy of scale by repeatedly building the same reactor design should bring costs down over time.
Fusion Is Hard
Considering all this, why have we not powered human civilization with nuclear fusion yet?
Well, the thing is that nuclear fusion is hard to achieve. Hydrogen atoms’ nuclei have a positive electric charge and naturally repel each other. So it can be very hard to get them close enough to each other for fusion, like 2 ultra-strong magnets repelling each other.
In nature, only the crushing gravity of an entire star is enough to push close enough hydrogen atoms to trigger fusion. Even something as big as Jupiter is still “too small” to achieve it. So, making hydrogen atoms come close together on Earth is very, very hard.
However, it has been done, and it was first achieved by a fusion machine in the 1950s. These machines demonstrated the feasibility of creating fusion but failed to return enough energy compared to the energy used to trigger it.
(Technically, large-scale nuclear fusion was achieved as early as 1952 with the first thermonuclear bomb, but this is hardly a usable technique for creating a safe power supply).
Another issue with fusion is that nuclear fusion plasma is extremely hot, usually above 100 million Celsius degrees. So it needs to be perfectly contained, or it will melt the reactor.
Because of all these problems to be solve, nuclear fusion has been a slow-moving field, with the sarcastic comment, “Fusion is always 30 years in the future”.
Making Fusion Happen On Earth
Scientists have managed nuclear fusion in experimental reactors for many years. Two main designs are used:
- One relies on lasers, concentrating a massive amount of power to hit a tiny hydrogen pellet and trigger fusion.
- The other uses a donut-shaped machine called tokamaks and ultra-powerful magnets to contain and compress the hydrogen into a self-igniting plasma.
The issue with fusion is that creating the right conditions with tens of millions of degrees is very energy-consuming. So even if we can make it happen, the fusion reaction tends to not produce enough energy back and turns out to be a net consumer of energy.
Plasmas are also very unstable, so it is hard to maintain the fusion reaction for longer than a few seconds.
The first tokamak was built in 1958, and they are considered the most likely designs to be able to sustain fusion for several minutes, or ideally hours, and produce positive energy returns.
Source: DOE
ITER is a tokamak design and will be the largest ever created nuclear fusion reactor, with 10x the plasma volume of the largest so far (JT-60SA in Japan) at 830 cubic meters (29,000 cubic feet).
Source: ITER
ITER Timeline
ITER is the heir to the International Tokamak Reactor, or INTOR, a collaboration between the West & Japan and the Soviet Union started in 1978.
The collaboration would persist even at the height of the Cold War. The first objective was decided in 1992, and the first Engineering Design Activities (EDA) were completed in 1998, with a design validated in 2001.
A heated discussion about the final design, which country would fund what, as well as where the reactor should be built, delayed for a time the project, until the site of Cadarache in France was chosen in 2005.
Source: Wikipedia
In that interval, China and South Korea joined the project in 2003 and India in 2005. Initial construction work started in 2007.
The machine assembly started in 2020, with the installation of the 1,250-tonne cryostat base in May 2020. The civil work (construction) of the site was finished in 2023.
Cryostat closure should be done by 2033. Full magnetic energy should be achieved by 2036, and the start of the deuterium-tritium operation phase in 2039.
ITER’s Budget
The initial budget of ITER was envisioned as “only” €6B in construction costs, but as it often happens for scientific megaprojects, it skyrocketed to a current estimate of $25.2 billion, while other estimated by the US Department of Energy put it more at $65B, something ITER has vehemently denied.
The project has so far generated 34,000 “job-years” and will generate another 74,000 job-years before completion of the construction.
ITER’s Objectives
The larger the plasma chamber, the more likely it is to be stable enough to produce positive energy returns.
But of course, the larger it is, the more expensive and complex it becomes.
The stated goal for ITER is to achieve a production of thermal energy 10x greater than the injected thermal power. The fusion pulse should last up to 8 minutes.
Combined together, these would mean the creation of 500 MW of heat in just 400-6000 seconds. It should reach as much as 150 million °C, or 10x the temperature at the core of the Sun.
To achieve these results, ITER will need to achieve a so-called “burning plasma”, where more than half of the energy received by the plasma comes from fusion reactions (instead of from external stimuli). Burning plasma is a must-do for any energy-positive, commercial power plant using nuclear fusion.
ITER energy generation will not be converted into electricity, as this is a technological demonstrator, and converting this heat into power is a well-known technology already routinely used in commercial fission nuclear power plants using uranium.
Another goal of the reactor is to test in real-life conditions key technologies that are still unproven, like superconducting magnets, remote handling (maintenance by robot), neutron shielding, heat conversion, and the concept of tritium breeding (see below).
DEMO Fusion Reactors
ITER would be followed by the DEMO-class of reactors, reusing ITER design (with potential improvement from experimental feedback), and these would form the 1st generation of commercial nuclear fusion power plants.
DEMO reactors are expected to produce 300 Megawatts to 500 Megawatts of net electricity to be delivered to the grid.
Among the major demo projects are:
- China: The Chinese Fusion Engineering Testing Reactor (CFETR) design was done in 2020, and should be built by 2040.
- Europe: The DEMO power plant should be built by 2050. A precursor to this project will be the building of a plasma-based volumetric neutron source (VNS) facility for testing the technologies considered for DEMO.
- Japan: JA-DEMO to be completed in the 2040s-2050s will aim for stable power generation beyond several hundreds of MW and fusion output of 1500 MW or higher.
- South Korea: K-DEMO will be built after 2050 while being preceded by a Virtual DEMO (V-DEMO) based on supercomputing, artificial intelligence, and digital twin technology.
- Russia: DEMO-RF should be built by 2055. A fusion-fission hybrid facility is also being considered.
- India: the country will focus first on a fusion pilot plant of 200–300 MW before building a DEMO reactor.
- USA: The US’s DoE is still considering the next steps, including partnering with private companies for the steps coming after ITER.
Tritium Breeding
As a project at the very cutting edge of science, there are a lot of concepts that need to be demonstrated experimentally.
A critical one is for the production of tritium, as ITER design relies on the fusion of deuterium and tritium (both isotopes of hydrogen).
Source: Climate & Hope
Deuterium-deuterium would be ideal, as deuterium is a naturally occurring element, but this would make artificial fusion much harder due to even higher required temperatures.
The issue is that tritium does not exist in nature and needs to be produced artificially in nuclear power plants (20kg per year globally). But ITER would consume all of Earth’s tritium production.
Anyway, future nuclear fusion reactors would not have enough tritium to produce energy, as every fusion reactor would require 100 to 200 kilograms per year.
So, tritium needs to be produced directly inside the reactor. This is the task of the “tritium breeding blanket.”
This 600 m² cover over the walls of the reactor, containing lithium, has the double task of creating energy when hit by neutrons (the base for future electricity production) while also producing tritium through the breakdown of the lithium atoms.
Source: C&EN
It should be noted that intermediary elements like beryllium ensure that at least 1 tritium is “regenerated” for every nuclear fusion reaction, by multiplying the number of neutrons.
In total, 6 different tritium breeding systems will be tested in ITER to determine the optimal material structure, cooling systems, liquid vs solid lithium, lithium extraction method, etc.
ITER’s Design
The Building Itself
While the interesting part regarding ITER’s engineering is in the advanced tech used for nuclear fusion, the building itself is massive and harbors not only high-tech elements but also all the support structures, energy supply, cooling systems, maintenance systems, etc.
Source: ITER
The ITER reactor itself is also massive, weighing 23,000 tonnes, 3x the weight of the Eiffel Tower. In total, 400,000 tonnes will rest on the lower basemat of the Tokamak Complex, or more than the weight of New York’s Empire State Building.
Source: ITER
To handle all of it, around 120,000 cubic meters of concrete were used during the civil works phase of the Tokamak Complex construction, with a large concrete plant built directly on-site to produce a wide range of concrete formulas, each adapted to the specific requirements of the ITER buildings and structures.
The building is also constructed with aseismic isolators, and protected by a nuclear-rated structure of reinforced concrete.
Logistics & Infrastructure
Another “basic” issue with the ITER project was the logistics of bringing all the large components built in specialized research institutes worldwide, on-site.
For example, each of ITER Tokamak’s 18 D-shaped toroidal field coils weighs 310 tonnes, and the heaviest elements, including the transport vehicle, weigh up to 900 tons. Thus, they must be shipped by sea instead of air.
They are then transported on a specially modified 104km road (64 miles), as some of the elements will be as long as 33 meters long (108 feet).
The installation also required a 400 kV power-line extension and extensive facilities for offices, workshops, equipment storage, and comfort.
Source: ITER
The construction itself, often requiring to fit in tight spaces, led to the design of more than 100 custom devices for the assembling of ITER machinery and buildings.
Source: ITER
The assembling of the tokamak, with its 1,000,000+ components, was a project in itself.
Superconducting Magnets
In the core of ITER machinery, the magnets will use superconducting strands of niobium-tin (Nb3Sn). In total, 100,000 kilometers (62,000 miles) of these strands will be needed, enough to wrap around Earth’s equator twice.
Source: ITER
This required a massive industrial production effort. Before the ITER scale-up, the global production of niobium-tin strands was just 15 tons/year. China, Europe, Japan, Korea, Russia, and the USA ramped it up to 150 tons/year.
Cryoplants & Cooling Tower
Superconducting magnets are only superconducting (no electric resistance) when ultracold. It is so cold that it is a mere 4.5 Celsius degrees above absolute zero.
Therefore, they require the cryoplant, a soccer-field-sized installation that stores helium and nitrogen to cool them and convert these gases to ultra-cold liquids.
Source: ITER
The 50 tons/day of liquid nitrogen is used as a pre-cooler for the liquid helium plant, and the liquid helium is used to cool the magnets. Nearly 25 tonnes of liquid helium at minus 269 °C will circulate in the ITER installation during operation.
While the magnet needs to be ultra-cold, the nuclear fusion will produce a peak heat load of 1150 MW, which needs to be evacuated. This is the task of the cooling tower.
Chemicals are injected to minimize corrosion of the piping and maintain the desired pH of the water. An ozone generation system maintains a continuous injection of ozone, which consumes organic material and prevents the growth of bacteria.
Magnet Power Conversion Buildings
Another system supporting the magnets, the power conversion turns the grid AC power into DC usable by the superconducting magnets.
Because of the massive intensity of the current used, traditional cables cannot be used to carry the power to the magnets.
Instead, steel-jacketed aluminum bars called “busbars”—actively cooled through a constant flow of pressurized water, are used. They are essentially power cords but thicker than train rails.
Source: ITER
In total 5 km (3.1 miles) of bipolar busbars will travel through the ITER complex.
Neutral Beam Injectors
Once the power supply and magnets are functioning, ITER needs to inject the deuterium that will power the fusion reaction.
The beam will use electric current to accelerate the particles to very high speeds, and inject 33 MW of the necessary 50 MW of input power. It then “neutralizes” them, allowing them to pass the magnetic field and communicate their energy to the plasma.
This will use more than 1MW of direct current voltage, a very exceptional amount. It will require custom-built components, going “beyond-state-of-the-art”, and fitting in an 11,700 m² building (126,000 square feet).
Source: ITER
As this is a key component, the Neutral Beam Test Facility (NBTF) was built in Padua, Italy. This should help clear a few technical obstacles, for example, that the particle beam used in ITER is much thicker than in previous nuclear fusion experiences.
Neutralizing the ions at this scale might also be difficult, and the real-life results will need to be tested before being installed in ITER.
Source: ITER
Cyclotron Heating
The other sources of heat to target the plasma are the electron and ion cyclotron heating systems. This includes the Electron Cyclotron Resonance Heating (ECRH) and the Ion Cyclotron Resonance Heating (ICRH).
They rely on high-frequency electromagnetic waves to create a resonance effect on the particles in the plasma, transmitting remotely power/heat into the core of the reactor. ECHR makes the electrons resonate with a 170 GHz frequency, while ICRH makes the ions in the plasma resonate with a 40-55 GHz frequency.
ITER’s Competitors
ITER is such a massive project that many of the scientists involved in its early design will probably not be around to see it operating.
This ambition can also be a limitation of the project. It is mostly based on fusion technology design from the late 1990s and early 2000s, lacking in assumption and technology choice.
This is because, since then, new fusion concepts have emerged, and several private companies are exploring ways to make nuclear fusion a reality with much less massive machinery.
This has even led some critics of ITER to call it “outdated”. The international nature of ITER, leading to some amount of bureaucracy and politics interfering with the science has also been described as a problem.
We discussed many of these fusion companies (mostly privately listed), like General Fusion, TAE Technologies, Helion, and Lockheed Martin Corporation in our article “Nuclear Fusion – The Ultimate Clean Energy Solution on the Horizon“, which also discusses alternatives to tokamak designs to achieve nuclear fusion.
Among the potential technological breakthroughs from these companies that are not going to be present in ITER’s design can be mentioned:
- Magnetized Target Fusion (MTF) technology.
- 3D printing of reactor components.
- Plasma gun, maybe more for fusion space propulsion than for energy production.
- Direct-electricity-capture from the plasma, using Faraday’s Law to induce a current instead of heat collection.
In December 2024, Commonwealth Fusion Systems (CFS) announced it is aiming for its ARC reactor to generate 400 MW for the Virginian power grid, which is enough to power 150,000 homes, with a start in the early 2030s (CFS uses high-temperature superconducting magnets).
Other technologies might help as well. A major one is AI, which might be used to detect and correct plasma instability in real-time.
Another one is potential room-temperature superconducting materials, which are now closer than ever. This would radically change the energy consumption of a reactor fusion, by making its magnets so much more energy efficient and reliable.
Conclusion
ITER might be one of the most important endeavors ever taken by mankind, on the same scale or maybe even more important than the Apollo program.
And while it is possible that private initiatives achieve commercial fusion before ITER, this is far from certain either.
If nuclear fusion is a technology requiring mega-reactors to be energy-positive and economically viable, it is likely that only an international effort like ITER can achieve it.
Even if it fails, it will have developed the industrial base and trained the scientific talent required for finding the key to nuclear fusion through other design choices. So in any case, it can hardly be considered a waste; especially when considering the impact nuclear fusion energy would have on mankind.
In the future, we can expect that ITER-like design will be improved with new technologies, including AI, room-temperature superconductors, direct electricity capture, etc.
It will, however, take more than another decade before ITER is running its experiments, making it one the most anticipated and most awaited science projects of this millennium.
ITER-Related Company
Mitsubishi Heavy Industry
Mitsubishi Heavy Industries, Ltd. (MHVYF +6.94%)
Many of the components built for ITER are one-of-a-kind designed by nuclear research institutes. But many others were built by industry leaders in the participating countries, bringing their manufacturing and engineering expertise to the scientific megaproject.
An important contributor is Mitsubishi Heavy Industry.
The company has a history going back as far as 1884, in shipbuilding. It later on started to manufacture heavy machinery, airplanes, trains, and automobiles.
In 1995, Mitsubishi Atomic Power Industry was integrated into the conglomerate, and has constructed 24 reactors in Japan.
Today, the company’s main source of revenue is energy systems (nuclear, gas, and steam systems) and logistics & thermal (HVAC, engines, turbochargers). It is the #1 globally in gas turbine and CO₂ capture system. It employs 77,000+ people, in 300 locations in the world.
Source: Mitsubishi Heavy Industry
Mitsubishi contributed to many core components of ITER, including the toroidal field coil (magnet), the divertor (plasma confinement), and the high heat flux components, including the plasma heating system.
Source: Mitsubishi Heavy Industry
Besides ITER, the company intends to capitalize on the restart of the nuclear industry in Japan, and the growing stream of nuclear projects globally. The company is also planning to develop its own SMR technology, as well as a fast reactor (burning nuclear wastes) and high-temperature gas-cooled reactor technologies.
Growing defense budgets should also benefit the aerospace and shipbuilding segments of the company.
In future technology, Mitsubishi is working on green hydrogen and green ammonia production, including the world’s first ammonia bunkering project in Singapore to power ships and gas turbines with ammonia instead of fuel and natural gas.
Carbon capture could also be a growing green activity, as well as high-efficiency cooling for data centers.
Source: Mitsubishi Heavy Industry
Overall, Mitsubishi Heavy Industry is a leader in many key technologies for the future, especially in cooling, energy production (gas and nuclear), and shipbuilding, as illustrated by being chosen to build many of the most important components of ITER.