Eli5: Before the first atom bomb was detonated, there was some speculation that the chain reaction would keep continuing and lead to burning up the atmosphere. So what actually limits the size of the explosion?

Question

Eli5: Before the first atom bomb was detonated, there was some speculation that the chain reaction would keep continuing and lead to burning up the atmosphere. So what actually limits the size of the explosion?

In: Physics

Answer 1

There is no limit to the size of the explosion. An H-bomb typically has two stages where the first stage is fission and the 2nd stage is fusion. X-rays from the fission ignite the fusion before the fission blast blows things apart. You can build a 3 stage bomb with two fusion stages. Or a 4 stage bomb and on and on ad infinitum. This according to “The Curve of Binding Energy” by John McPhee.