Fusion Q&A
What is ITER?
Short answer
ITER (International Thermonuclear Experimental Reactor) is the world's largest fusion experiment, under construction in Cadarache, France by a 35-nation collaboration. Its goal: 500 MW of fusion power from 50 MW of heating — a tenfold gain (Q = 10) — sustained for minutes. First plasma is targeted for 2034.
Mission and scope
ITER is the most thoroughly engineered fusion device ever built — and the only one designed to validate burning-plasma physics at full reactor scale. It will not produce commercial electricity; its successor DEMO reactors will.
The collaboration includes the EU, US, China, India, Japan, Korea, and Russia. Total construction cost estimates exceed $25B.
Frequently asked
- When will ITER produce first plasma?
- 2034 under the revised baseline announced in 2024.
- Will ITER produce electricity?
- No — ITER is a research device. Its successor DEMO reactors will produce electricity in the 2040s.
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