I read that the creator of the Czar Bomba, is that what it was called, knew that after a certain amount of plutonium, the explosion would be no greater. I forget his reasoning.
Anybody know anything about that?
Can you make a bomb that could engulf the world if it had enough plutonium in it?
I know when they tested the hydrogen bomb at sea and the explosion kept going on, some scientists were afraid the earth’s atmosphere would catch fire and that would be the end of life on Earth.
The bomb was 'detuned' from a nominal 100 MT yield to a nominal 50 MT yield and yielded 57 MT. A 50 MT blast will give you a fireball about 7 miles in diameter and the troposphere is about 7 miles in thickness. Anything greater gives a fireball large enough that a lot of the energy is wasted by escaping uselessly into the stratosphere.
In theory, you can make a bomb with a yield just about as large as you want but there are utilitarian limits to what one might want to build. If one wants to devastate an opponent the results of several smaller bombs well placed can be much more effective than one big one.
Plutonium may be the trigger (or highly enriched uranium) but the yield comes largely from the fusion of a fuel such as lithium deuteride.
Of course, this all applies to fusion devices, primarily. For a fission only device there is no fusion fuel and the yields are considerably less.