system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: How reactors don't melt if stuff going on inside them hit millions of degrees?

So I just read an article about a Chinese fusion reactor that got to 50million degrees celsius and managed to hold that for a little over a minute. Also, I've read that the LHC managed to generate 5.5 Trillion degrees celsius years ago which was said to be times something something hotter than the sun.  
  
How on earth did everybody not die and melt? If you search for highest melting points its all just a few thousand degrees. What is going on here?
gpt
What's going on here is they keep the stuff that's millions of degrees from touching anything else, and they only use very very tiny amounts of the stuff they're heating up. 

The most common way of doing this is to trap the little wee cloud of hot hot stuff within a very strong magnetic field. Because it's not touching anything, the heat it contains isn't conducted into the structure around it that's generating that magnetic field, and they can keep pumping more energy in. When they release it, there's so little hot stuff there that it doesn't really heat up its surroundings enough to damage them.