---
title: ITER Tokamak Fusion Reactor
type: technology
url: "https://www.envisioning.com/research/grid/europe__iter-tokamak-fusion-reactor"
hub: grid
summary: "The world's largest fusion experiment under construction in France — international megaproject demonstrating net energy gain from plasma confinement"
---

# ITER Tokamak Fusion Reactor

The world's largest fusion experiment under construction in France — international megaproject demonstrating net energy gain from plasma confinement
- Technology Readiness Level: 5/9
- Impact: 4/5
- Investment: 2/5
ITER (International Thermonuclear Experimental Reactor) is being built in Cadarache, France, by a consortium of the EU, US, China, Japan, Russia, South Korea, and India. It is the world's largest tokamak fusion reactor, designed to demonstrate that fusion can produce net energy — generating 500 MW of thermal power from 50 MW of heating input.

The project has experienced significant delays and cost overruns (current estimates exceed €20B), but a 2026 progress report confirmed continued advancement toward first plasma. The ITER Council endorsed the revised timeline, and machine assembly is ongoing. The feasibility of the next step — the DEMO demonstration reactor — depends on ITER's results.

Regardless of timeline criticisms, ITER represents the most advanced fusion engineering project ever attempted. The technologies developed for ITER — superconducting magnets, plasma heating systems, tritium handling, materials science — are being commercialized by private fusion startups worldwide. Europe hosts ITER and maintains the deepest institutional knowledge of tokamak engineering.

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Source: Envisioning — Technology Research Institute (https://www.envisioning.com/research/grid/europe__iter-tokamak-fusion-reactor)