Technically correct, but in this case I’m wondering what is stopping fusion from continuing longer than about 20 minutes.

Is it like rail gun technology, where the hardware fails after so much use and there is no realistic way to keep it in tolerance?

Are we having trouble keeping a balance between fuel and the reaction, causing it to fizzle out or breach containment?

Is the fuel actually too expensive?

Is all this ok and we are now stuck with a scaling issue where the reaction can sustain itself, but we can’t actually use it to boil more than a kettle.