modeling calibrated predictions exploring critical wisdom crowdsourcing critical contingencies computing probable insights calculating calibrated insights mapping the future formulating accurate forecasts aggregating critical forecasts modeling precise futures crowdsourcing definitive futures aggregating critical forecasts crowdsourcing precise contingencies exploring quantitative wisdom predicting precise contingencies


Metaculus Help: Spread the word

If you like Metaculus, tell your friends! Share this question via Facebook, Twitter, or Reddit.

Will the International Thermonuclear Experimental Reactor start operating by end of 2025?

The International Thermonuclear Experimental Reactor (ITER) is an international nuclear fusion research and engineering megaproject. It is an experimental tokamak nuclear fusion reactor which will be the world's largest magnetic confinement plasma physics experiment.

With thirty-five participating nations and an expected price tag in excess of €20 billion, it is one of the largest international scientific megaprojects.

ITER began in 1985 as a Reagan–Gorbachev initiative with the equal participation of the Soviet Union, the European Atomic Energy Community, the United States, and Japan through the 1988–1998 initial design phases.

The project aims to:

  • Momentarily produce a fusion plasma with thermal power ten times greater than the injected thermal power (a Q value of 10).

  • Produce a steady-state plasma with a Q value greater than 5. (Q = 1 is scientific breakeven)

Currently, it aims to produce its first "small star" inside the ITER Tokamak in November 2025.

By the end of 2025, will ITER announce to have successfully discharged a plasma pulse of at least 5 kiloampere?

For the purpose of this question a lower threshold of 5kA is included to exclude insignificant results counting toward positive resolution. For reference, a Tokamak with a major plasma-radius of 0.9 m (much smaller than the ITER's 6.2m radius), achieved a 10kA first plasma discharge pulse in 2017.


Metaculus help: Predicting

Predictions are the heart of Metaculus. Predicting is how you contribute to the wisdom of the crowd, and how you earn points and build up your personal Metaculus track record.

The basics of predicting are very simple: move the slider to best match the likelihood of the outcome, and click predict. You can predict as often as you want, and you're encouraged to change your mind when new information becomes available.

The displayed score is split into current points and total points. Current points show how much your prediction is worth now, whereas total points show the combined worth of all of your predictions over the lifetime of the question. The scoring details are available on the FAQ.

Note: this question resolved before its original close time. All of your predictions came after the resolution, so you did not gain (or lose) any points for it.

Note: this question resolved before its original close time. You earned points up until the question resolution, but not afterwards.

This question is not yet open for predictions.

Thanks for predicting!

Your prediction has been recorded anonymously.

Want to track your predictions, earn points, and hone your forecasting skills? Create an account today!

Track your predictions
Continue exploring the site

Community Stats

Metaculus help: Community Stats

Use the community stats to get a better sense of the community consensus (or lack thereof) for this question. Sometimes people have wildly different ideas about the likely outcomes, and sometimes people are in close agreement. There are even times when the community seems very certain of uncertainty, like when everyone agrees that event is only 50% likely to happen.

When you make a prediction, check the community stats to see where you land. If your prediction is an outlier, might there be something you're overlooking that others have seen? Or do you have special insight that others are lacking? Either way, it might be a good idea to join the discussion in the comments.

Embed this question

You can use the below code snippet to embed this question on your own webpage. Feel free to change the height and width to suit your needs.