Because ITER is not designed to be running for more than a few minutes at a time. Its successor, DEMO, will be designed for continuous power output. https://en

Because ITER is not designed to be running for more than a few minutes at a time. Its successor, DEMO, will be designed for continuous power output. https://en.wikipedia.org/wiki/DEMOnstration_Power_Station https://en.wikipedia.org/wiki/DEMOnstration_Power_Station