Anyone care to ELI5 how something that is the hottest thing in the solar system by x10 @ 120million degrees doesn't melt the very thing containing it. I understand powerful magnets contain the plasma but does that mean that there is little to no radiated heat? If that's the case how do they actually get the energy out?
I am not a
lawyer physicist, but I'll have a go at saying how I think it works...
The amount of heat energy in some stuff is determined by both its temperature and its mass. The plasma in a fusion reactor has an enormous temperature but a low mass - at any given time there's not much fuel in the reactor. So the amount of heat energy in the plasma is far,
far lower than the mind-boggling temperature of it might lead a person to expect. It's still a lot, but nothing unusual for a power station. Business as usual for a power station - use the heat to boil water, use the steam to turn a turbine, use the turbine to spin magnets around a wire, electricity results.
It makes more sense on a more comprehensible scale. Imagine a room with a large radiator and a tea light candle. The water in the radiator is at maybe 60C, the candle flame is at maybe 1000C. But the radiator will have a lot more heat energy than the candle flame.
Continuing the analogy...the candle flame will set fire to stuff touching it, but it won't turn the room into an 800C oven that will kill you. For the candle flame and for the fusing plasma, as long as you keep it away from stuff things are OK. The fusing plasma would actually be
less dangerous than the candle flame if it touches stuff. A plasma containment failure in a fusion reactor won't set fire to the place and burn it down. As long as the reactor has been built at least somewhat sensibly, containment failure won't be particularly dangerous. It won't do the reactor chamber much good, but the rest of the facility should be undamaged and outside it will be fine. It wouldn't be like a meltdown in a fission reactor.