>>11033769 pb notable

A 120-300 kiloton bomb would almost certainly involve fusion and would not be a pure fission device. There are several reasons for this:

It would require a lot of enriched uranium. A waste

It would involve multiple critical masses of uranium. Very dangerous

Because of the above, a needlessly complex design

The US' Ivy King test was the largest pure fission bomb every detonated, at 500 kilotons. It involved 4! critical masses.

So, the most likely bomb that was tested by NK was a fission bomb that was boosted. Boosting just puts a small amount of deuterium or tritium in the center of an implosion device. You get an extra kick from the fusion burn.

A full thermonuclear bomb is also possible. I think that would be unlikely if developed natively. But certainly possible with Chinese assistance. Or just straight up, a device from China.

Not sure if this is useful but thought I'd share.

https://en.wikipedia.org/wiki/Operation_Ivy

>>11034472

I guess I'll add a bit more to this.

A 120 kiloton bomb would be at the upper end of boosting. I don't know offhand what the largest boosted device was. But it's purpose is primarily to get a bigger bang from a smaller package. So most of the tests with boosting were probably 35kt-100kt. I'd have to look it up.

At the upper end, 300 kilotons, this was probably a thermonuclear weapon. A fusion bomb ignited by a fission reaction.