What happens to the enriched uranium if Trump blows Iran off the face of the earth?

Trump is once again threatening to blow Iran off the face of the earth. I see 2 major problems with that.
One: When Trump first started talking about invading Iran he said it was because the protesters in Iran were being arrested and executed. Were are those people going to go if their homes are blow off the face of the earth?
Two: What about the enriched uranium - will it get into the atmosphere and spread around the world? Maybe Trump was Lying about Iran having stock piles of enriched uranium and it won't be as bad. Cheers!