Gotchas, tools, jigs, and tricks of design, manufacturing, maintenance, and support, as well as the very rare materials, are the most crucial bits to guard.
IIRC, the manufacturing of a low-yield, simple fission device based on an old design isn't complicated; it's the fissile materials that are the show-stoppers, hence nonproliferation of centrifuges, dual-use components, and yellowcake/ore.
Reminds me of a factory tour I went on where a big fancy robot was assembling car parts. I was told not to take photos — not because the robot was secretive (and in fact the same one was used in several factories), but because the computer screen beside it showed details about the specific configuration of that robot. There were hundreds of different settings that could be tweaked and that was the competitive advantage.
Makes sense. I toured the Dell factory in Round Rock, and it was the same deal. I think all businesses attempt to limit information disclosure as a standard practice, even if there aren't obvious trade secrets, because there maybe unrecognized intelligence in them.
> Emails from reporters started coming in last night. Could I comment on the leaked National Security Agency (NSA) report on Russian interference in the election?
> The short answer was no. The reason was simple: I couldn’t read it.
> As one of the 5.5 million Americans who hold a security clearance, viewing that document would violate my obligation to protect classified information.
Sometimes what you don't say reveals as much as what you do. This is the origin of the Glomar Response. By never providing information it is harder for third parties to tell when something is really secret or just public knowledge. This keeps the actual secret things that much more obscure. If I ask you ten questions and you answer four of them I learned something about all ten topics. If you refuse to give me useful information on all of them I learn nothing.
I suspect this solution makes sense in the short run. In the long-run it makes it so any organizational incompetence can be covered up with "it's classified". Over 80+ years the organization starts to struggle with basic reality.
I wouldn't be surprised if the CIA is filled with Byzantine Bureaucracy, fiefdoms, and departments that don't even know what they are supposed to do. In a kafka-esque twist I'd bet there are individuals who aren't even allowed to know their own job description due to some papered over incompetence.
IIRC, the manufacturing of a low-yield, simple fission device based on an old design isn't complicated; it's the fissile materials that are the show-stoppers, hence nonproliferation of centrifuges, dual-use components, and yellowcake/ore.