Why is the second guaranteed to be smaller?
We know how nuclear bombs work. The majority of the energy comes from nuclear fusion, a highly exothermic process, that can (in the foreseeable future) only be used in bombs.
If we don’t need to drop the bomb, but rather assemble it in place, it can just use deuterium as a fusion fuel. Deuterium can be distilled from normal water for much less energy that it generates in fusion.
Edit: mixed up fusion and fission in the first statement
It does in modern designs, the first time it happened was in 1952.
To quote Wikipedia:
The first thermonuclear weapon detonation, where the vast majority of the yield comes from fusion, was the 1952 Ivy Mike test of a liquid deuterium-fusing device.
Why is the second guaranteed to be smaller?
We know how nuclear bombs work. The majority of the energy comes from nuclear fusion, a highly exothermic process, that can (in the foreseeable future) only be used in bombs.
If we don’t need to drop the bomb, but rather assemble it in place, it can just use deuterium as a fusion fuel. Deuterium can be distilled from normal water for much less energy that it generates in fusion.
Edit: mixed up fusion and fission in the first statement
Yes, from an extremely inefficient fission reaction that can be improved by an order of magnitude by doing it slowly in a reactor.
Mixed up fission and fusion there, they sound so similar in English.
The comment talks about fusion.
Most of the energy does not come from fusion.
It does in modern designs, the first time it happened was in 1952.
To quote Wikipedia:
https://en.m.wikipedia.org/wiki/Nuclear_fusion