Subject: The difference between a nuclear reactor and a nuclear bomb.

I have trouble explainging the difference between the reactor and the bomb.
Could you put it into words that would be effective.
I have gone through the fission definition and the radiation decay  discussion 
but here seems to be some confusing information on the internet which states 
that critical mass and fission are part of the nuclear power plant reactor core 
operation.  Could you clarify this.
The critical mass required for fission is not possible outside of the chain 
reaction used in the nuclear bomb because it consumes all of the material that 
is fissionable.  
That is my explanantion.
Can you provide a better one?
Sincerely,
Azel Beckner

Re: The difference between a nuclear reactor and a nuclear bomb.