> I am speculating here, but it seems like DoE must believe that anything beyond simple shapes may provide bad actors (i.e. anyone but US Govt and allies) clues as to how to build a thermo-nuke.
It's a bit like the Egg of Columbus. Doing it the first time needs a team of visionary geniuses, but once the trick is known to work then even us pedestrians could manage it given enough time and resources.
the problem is usually getting the fissile material.
as far as non-state actors go though, other types of WMD are probably more attainable. Aum Shinrikyo is probably the most infamous example where a cult manufactured multiple chemical weapons. https://en.wikipedia.org/wiki/Aum_Shinrikyo#Tokyo_subway_sar...
Yes and no. For terrorism purposes, the primary (more or less the same as a "Hiroshima"-level "A"-bomb) would surely more than suffice.
I'm sort of struggling to think why anyone other than a nation state (looking to prove itself worthy of a seat at various tables) would want to possess more bang than that.
Granted there are a few nations at or close to A-bomb tech whom we would definitely not want having its bigger brother. Iran and NK especially.
I feel like the Nth Country Experiment kind of invalidates the idea that it makes sense to worry so much about hiding all of this, though? That 3 fresh physics PhDs were able to design a working bomb in as many years without having subject matter expertise to me shows that shows that the sort of adversary that has the resources to build such a project will have access to the resources to design it, too.
And with good reason: https://www.theguardian.com/world/2003/jun/24/usa.science
It's a bit like the Egg of Columbus. Doing it the first time needs a team of visionary geniuses, but once the trick is known to work then even us pedestrians could manage it given enough time and resources.