Cluster 1 · What ITER is
ITER — precisely what it is and is not
ITER is a giant scientific experiment designed to prove that nuclear fusion can produce more energy than it consumes. Fusion is the reaction that powers the sun — hydrogen atoms fuse together under extreme heat and pressure to form helium, releasing enormous amounts of energy. On Earth, doing this requires temperatures of approximately 150 million degrees Celsius — ten times hotter than the sun's core. ITER uses powerful magnets to contain this superheated plasma. If it works, fusion could eventually provide clean, inexhaustible energy — hydrogen fuel from seawater, no carbon emissions, no long-lived radioactive waste. ITER is not a power plant — it will not generate electricity. It is the scientific experiment that must succeed before a power plant can be designed.
The Q factor: ITER's primary goal is Q=10 — producing 500 megawatts of fusion power from 50 MW of heating input. Current record: JET (Joint European Torus, Culham, UK) achieved Q≈0.67 in 2022 — producing 59 MJ of fusion energy from 0.2 MJ of input energy during a 5-second pulse.
The plasma: ITER will heat a mixture of deuterium (D) and tritium (T) to approximately 150 million°C. At this temperature, D and T nuclei overcome their electromagnetic repulsion and fuse: D + T → ⁴He + n + 17.6 MeV. The neutrons carry 80% of the fusion energy; they are absorbed in a "blanket" surrounding the plasma and their heat will eventually be used to generate steam (in a future power plant). The helium (alpha particle) carries 20% and heats the plasma, sustaining the reaction.
Timeline: First plasma (hydrogen): 2025 (revised). Full deuterium-tritium operation: 2035+. The original 2016 timeline was extended multiple times due to construction complexity. Source: ITER Organisation Newsline
The plasma: ITER will heat a mixture of deuterium (D) and tritium (T) to approximately 150 million°C. At this temperature, D and T nuclei overcome their electromagnetic repulsion and fuse: D + T → ⁴He + n + 17.6 MeV. The neutrons carry 80% of the fusion energy; they are absorbed in a "blanket" surrounding the plasma and their heat will eventually be used to generate steam (in a future power plant). The helium (alpha particle) carries 20% and heats the plasma, sustaining the reaction.
Timeline: First plasma (hydrogen): 2025 (revised). Full deuterium-tritium operation: 2035+. The original 2016 timeline was extended multiple times due to construction complexity. Source: ITER Organisation Newsline
Source: ITER Organisation · JET EUROfusion results 2022
ITER uses a tokamak (toroidal magnetic confinement). Key parameters: major radius R = 6.2 m, minor radius a = 2.0 m, plasma volume = 840 m³. Magnetic field: 11.8 T at the plasma axis (central solenoid). Plasma current: 15 MA. The 18 toroidal field (TF) coils weigh 300 tonnes each and are cooled to 4.5 K (-268.7°C) using superconducting Nb₃Sn cable-in-conduit conductors. The central solenoid (CS) — the world's most powerful superconducting magnet — exerts a lifting force equivalent to 2 × Boeing 747. Total superconducting strand: 100,000 km. The ITER tokamak assembly building is 60 m tall, 80 m wide. Total weight of the Tokamak Complex: 400,000 tonnes of concrete + 23,000 tonnes of machine. India (ITER-India) manufactures: vacuum vessel ports (9 of 18 upper ports), cryostat thermal shields, in-wall shielding, and diagnostics. Source: ITER Technical Basis Document · ITER-India BARC
Source: ITER Organisation Technical Basis · ITER-India/BARC official communications
Cluster 2 · International dimensions
35 nations — and India's role
Who is building ITER
ITER is funded and built by seven Members: European Union (host, 45.46% of costs), China, India, Japan, South Korea, Russia, USA (each ~9.09%). All 35 ITER member nations contribute through their respective Member organisations. The EU hosts ITER at Cadarache and contributes the largest share. Member contributions are primarily "in kind" — building and delivering components manufactured in their own countries — rather than cash transfers.
Cost overruns and schedule delays have been a persistent challenge. The 2006 estimated cost of €5 billion grew to approximately €20+ billion by 2020. Source: ITER Organisation — Member Parties
Cost overruns and schedule delays have been a persistent challenge. The 2006 estimated cost of €5 billion grew to approximately €20+ billion by 2020. Source: ITER Organisation — Member Parties
India's role in ITER
India joined ITER in 2005. ITER-India is managed by the Institute for Plasma Research (IPR), Gandhinagar, Gujarat. India manufactures and delivers: vacuum vessel ports (9 of 18 upper ports), cryostat thermal shields (upper and lower), in-wall shielding blocks, diagnostic neutral beam, and electron cyclotron heating systems.
India's IPR is also building SST-1 (Steady-State Superconducting Tokamak) at Gandhinagar (23.27°N 72.64°E) — India's own fusion research device, focusing on steady-state plasma operation. India's participation in ITER has advanced its domestic fusion and plasma technology capability significantly. Source: ITER-India · Institute for Plasma Research, Gandhinagar
India's IPR is also building SST-1 (Steady-State Superconducting Tokamak) at Gandhinagar (23.27°N 72.64°E) — India's own fusion research device, focusing on steady-state plasma operation. India's participation in ITER has advanced its domestic fusion and plasma technology capability significantly. Source: ITER-India · Institute for Plasma Research, Gandhinagar
Questions
Is ITER commercial fusion energy?
No. ITER is a scientific experiment — it will not generate electricity. Its purpose is to demonstrate Q=10 (10 times more fusion power out than heating power in) and to test the plasma physics, materials, and engineering required for a commercial fusion power plant. The next step after ITER is DEMO (DEMOnstration Power Plant) — which would be designed to actually generate electricity. Multiple private fusion companies (Commonwealth Fusion Systems, TAE Technologies, Helion Energy, General Fusion) are also pursuing different approaches to commercial fusion and claim to be on faster timelines than ITER. Source: ITER Organisation · Fusion Industry Association 2024.
Source: ITER Organisation · Fusion Industry Association Global Fusion Report 2024
Will fusion energy ever be practical?
Fusion has been "30 years away" for the past 70 years — a running joke in physics. The genuine reason: the plasma physics challenges turned out to be far more complex than initially expected. However, significant progress has been made. JET achieved a Q≈0.67 record in 2022. NIF's inertial confinement fusion achieved ignition (Q>1 in a pulse) in . Private companies are investing billions (CFS raised $1.8 billion, raised by Bill Gates, Google, Khosla Ventures; Helion raised $2.2 billion with Microsoft signing a power purchase agreement). ITER, if successful, will prove Q=10. The path to commercial fusion electricity is: ITER (Q=10 scientific demonstration) → DEMO (electricity generation demonstration) → commercial plant. Optimistic timelines suggest commercial fusion electricity in the 2040s–2060s. The IEA does not include fusion in its 2050 energy projections due to timeline uncertainty. Source: Fusion Industry Association · ITER Organisation.
Source: Fusion Industry Association Global Fusion Report 2024 · ITER Organisation · NIF announcement
What is India's contribution to ITER specifically?
India's contribution to ITER is managed by ITER-India, based at the Institute for Plasma Research (IPR) in Gandhinagar, Gujarat (23.27°N 72.64°E). India's specific manufactured components include: (1) 9 of 18 upper port plugs (vacuum vessel access ports used for diagnostics and heating systems); (2) Cryostat thermal shields — the insulating barrier between the room-temperature outer structure and the −269°C superconducting magnet systems; (3) In-wall shielding blocks that protect the toroidal field coil casings; (4) Diagnostic neutral beam system; (5) Electron cyclotron heating system. India's total contribution value is approximately €900 million in in-kind components. ITER-India's participation has significantly advanced India's domestic fusion and plasma technology capability — the same engineers work on India's SST-1 (Steady State Superconducting Tokamak) fusion device also at IPR Gandhinagar. Source: ITER-India/IPR · Department of Atomic Energy, Government of India.
Source: ITER-India official documentation · IPR Gandhinagar · DAE India
What are private fusion companies doing and how do they differ from ITER?
At least 40 private fusion companies exist globally (Fusion Industry Association 2024), pursuing faster routes to commercial fusion than ITER's government-led approach. Key companies: Commonwealth Fusion Systems (CFS, MIT spinout, Cambridge MA, 42.35°N 71.10°W) — raised $1.8 billion; demonstrated 20T high-temperature superconducting (HTS) magnet in 2021; building SPARC tokamak, targeting commercial electricity by 2030s. Helion Energy (Redmond WA) — raised $2.2 billion; signed power purchase agreement with Microsoft; inertial-electrostatic confinement. TAE Technologies (California) — field-reversed configuration; pursuing hydrogen-boron fusion (no neutrons). General Fusion (Vancouver) — magnetized target fusion using steam-driven pistons. The key difference from ITER: private companies use novel approaches, faster timelines, and smaller scales. ITER is a 35-nation scientific experiment; private companies are racing to commercial electricity. Source: Fusion Industry Association Global Fusion Report 2024.
Source: Fusion Industry Association Global Fusion Industry Report 2024 · CFS press releases
What fuels does ITER use and why are they hard to obtain?
ITER burns deuterium (D) and tritium (T) — two heavy isotopes of hydrogen. Deuterium (one proton + one neutron) is abundant: it constitutes approximately 0.0156% of natural hydrogen and is easily extracted from water by electrolysis. Tritium (one proton + two neutrons) is the challenge: it is radioactive (half-life 12.3 years) and extremely rare in nature — the Earth's natural inventory is approximately 3.5 kg. Tritium is primarily produced in nuclear reactors as a by-product of neutron bombardment of lithium-6. Global tritium inventory is approximately 25 kg, most produced in CANDU reactors in Canada. ITER needs approximately 1 kg of tritium per year to operate — the global supply is barely sufficient. Future commercial fusion reactors would "breed" their own tritium using lithium blankets that absorb the fusion neutrons: Li-6 + n → T + He-4. This "tritium breeding" technology is one of the key engineering challenges of commercial fusion. Source: ITER Organisation · Fraunhofer ISE · Canadian Nuclear Safety Commission (tritium supply data).
Source: ITER Organisation technical documentation · Canadian Nuclear Safety Commission tritium reports
How hot is the plasma in ITER and why is that hotter than the sun?
ITER's plasma will reach approximately 150 million degrees Celsius — approximately 10 times hotter than the sun's core (~15 million°C). The reason ITER must be hotter than the sun: on the sun, fusion happens under enormous gravitational pressure (the weight of the entire star's mass). On Earth, we cannot replicate that pressure — so we compensate by using far higher temperatures to give hydrogen nuclei enough kinetic energy to overcome their electrostatic repulsion and fuse. At 150 million°C, hydrogen nuclei move fast enough to fuse when they collide, even without gravitational confinement. The plasma is contained by the magnetic field (not by the vessel walls — contact would instantly cool the plasma and melt any material). This is why the tokamak design uses superconducting magnets — to create a magnetic "bottle" that holds the 150 million°C plasma while the surrounding magnets are at −269°C, a temperature range of approximately 150 million degrees across a few centimetres. Source: ITER Organisation · Eurofusion.
Source: ITER Organisation · EUROfusion educational materials
ITER OrganisationTechnical specifications · Timeline · Member Parties · Newslineiter.org
ITER-India / IPRIndia's ITER contributions · SST-1 deviceiter-india.org
EUROfusion / JETJET 2022 record 59 MJ fusion energy · Q factor resultseuro-fusion.org/jet-record
Fusion Industry Assoc.Global Fusion Industry Report 2024 · Private company fundingfusionindustryassociation.org