For anyone interested in the basics of nuclear weapons, I highly recommend the "Nuclear 101: How Nuclear Bombs Work" lectures by Matthew Bunn, a man heavily involved in nuclear arms control.
His lectures are always highly entertaining, a real pleasure to watch.
This is a clip from his lecture explaining the basics of thermonuclear warheads:
Given the nature of nuclear weapons work, isn't anything presented by someone basically speculation? If he actually had the information he wouldn't be able to talk about it. He seems to have been involved at the government level in the storage and handling of weapons, not production of them.
Fun idea, there basically are no nuclear secrets. If you look long enough you can pretty much learn everything except some in the weeds details of the most modern nuclear warheads. My basic premise is all our “enemies” have this info by now and the complexity is actually in building them, not how they work or how to build them.
As search engines continue their trend of considering your search term just a suggestion, I can't pull it up, but there's also a case where a high school physics class decided to try to design one and also came adequately close.
The hard thing that is actually the stopper is the enrichment of the relevant materials. The other hard part is getting the best possible yield; there's huge variances in what you get from the same amount of fuel depending on how well you can put it together before it blows itself apart, but that's not a stopper for a terrorist group. Getting to Hiroshima levels is apparently not that difficult, as evidence by the fact it was done so many decades ago.
Delivery is another major challenge, but I'll consider that separate from the task of creating one at all.
This is concept is a neat one that I think differentiates the real world from many fantasy worlds. In the latter, many of the core problems are built around somebody having "forbidden" or "dark" knowledge, or the heroes needing to find just the right rare answer to some kind of fundamental problem that somebody wrote down but that was suppressed. Think Horcruxes in Harry Potter sort of a deal.
In the real world, we have classification, but by-and-large those are about very specific elements of very specific things (i.e. the exact shape/location of that secondary, not that the secondary exists or that Sandia does modeling of that sort of thing). No one's really the gatekeeper of knowledge of things like nuclear engineering or biological gain-of-function. There's not really a litmus test for someone to attend to a microbiology graduate program or take a chemistry class that would enable them to develop synthetic drugs.
Same thing with martial arts; no one's hiding some secret martial technique. A BJJ purple belt will, in a fistfight, toy with just about anyone else on the planet not trained in jiujitsu like they're a toddler. And you can just, like, walk into many strip malls across the North America, pay your $200/mo, and a few years later of consistently showing up, you're there. No secret death touch or spiritual clarity needed.
Funny example. I am a BJJ purple belt. I love BJJ analogies. It is analogous to the mental work in tech. There is just hard, physical work, repetition, analysis, and more work. It’s very rewarding. Just like tech problem solving. That’s the secret to most things. Hard, sometimes wearying, sometimes joyful, work.
I think secrets are largely against the ideals of the enlightenment. There are certain temporal operational concerns. Democracy dies the death of a thousand cuts when unelected bureaucrats classify the most mundane things by default “just in case”. 9/11 happened because of these silos. Our foreign adversaries often know more about what we are up to than US citizens, etc.
Using publicly available knowledge won't get you a working nuke, even if you have the necessary fissile material. A lot of finicky details have to be just right in order to get a nuclear explosion instead of a fizzle. C.f. https://en.wikipedia.org/wiki/Fogbank
More often than not, comparatively simple chemical reactions are hard to reproduce reliably just by reading the research papers.
I have watched a lot of Nile Red and agree with this. The actual things that happen that kick off the nuclear reaction are kind of crazy and I can see how it would be very difficult. However, you know it is possible and the shape and structure of it. Any nation state has the resources to do it and it would not take them very long because the physics are all sorted. I actually kind of doubt America could even just produce another nuclear weapon on demand because we have lost a lot of the how-to institutional knowledge.
I think enough is known now to really narrow down the problem to something a nation state can do.
There was once an article in a pop sci magazine 25 odd years ago about how to build a nuke in a house; basically a pipe / barrel from the attic to the basement, a concave bit of plutonium or the right kind of uranium in the basement encased in a good carrier like concrete, and a convex matching part at the top of the barrel. Explosives behind the top one, launch the one towards the other, ????, nuke. In theory.
That said, if it was that easy, I'm sure we would've had terrorist attacks with nukes already. Or if terrorism was that big an issue. I don't know if it hasn't happened yet because technology and three-lettered agencies are doing their job right though.
Casting, machining or welding plutonium into the right shapes and purities without killing your self, or some of the other exotic metals, without killing your self or making your neighbours sick in a sub 1-3 week horizon is incredibly challenging. The exact geometries you need to achieve aren’t easily available either neither is measuring is you achieved them without again killing your self.
Getting a dirty fizzle is a lot easier which is why people are afraid of dirty weapons by terrorists.
Getting the right type of plutonium in sufficient quantity is an order of magnitude harder than either of them - there is essentially no naturally occurring plutonium, it only comes as a side effect of neutron bombardment of specific isotopes of Uranium, which are already hard to seperate, and only under specific conditions are the right types of plutonium isotopes to be useful produced. And even then, it’s non trivial to seperate them.
The whole thing is a giant, high profile, and dirty mess.
Making the entire thing efficient enough to actually be delivered to a target is also another matter. This requires precise calculation of the geometries and very precise grades of plutonium, barrel pipe, and explosives. How do you even keep the gun type shapes from deforming in the barrel?
[Cut to me in 1999 driving my old station wagon down to the local hardware store to pick up a few kilos of highly purified enriched uranium and some C4]
>> ,I'm sure we would've had terrorist attacks with nukes already. Or if terrorism was that big an issue
There are two problems with that statement. Let’s examine them
Firstly, does majority of terrorists want to nuke NewYork? If you gave 9/11 bombers a 5 megaton warhead, would they use it? You have to remember that many of them imagine they have a just cause.
Second, imagine you are could make a nuke at home and were completely immoral, who would you sell it to?
There are many evil governments and organisations that could pay more and be better clients than terrorists.
The hardest part of building nukes is acquiring weapon-grade enriched uranium, because it's controlled as hell and you will get bombed if you try to make your own.
If you spend hundreds of millions of dollars on enriched uranium, paying salaries for team of engineers is the easy part.
North Korea, Pakistan, India, South Africa & likely Israel didn't get bombed due to their enrichment programs.
There is a rumor that the USSR flirted with the idea of a pre-emptive strike on Mainland China to decapitate their nuclear program after the Sino-Soviet split. This did not happen obviously.
Iran didn't get bombed, although that may just be because other forms of sabotage were available.
Syria & Iraq on the other hand, yeah those got bombed. But it's not 100% a guarantee.
The fact nukes are hard to make aren't because of lack of knowledge, everyone knows how to make nuclear weapons - the issue is materials. Control of them is closely guarded and you tend to get disappeared or bombed if you make them yourself.
His lectures are always highly entertaining, a real pleasure to watch.
This is a clip from his lecture explaining the basics of thermonuclear warheads:
https://youtu.be/YMuRpx4T2Rw
And the full “Nuclear 101” lecture, in two parts:
https://youtu.be/zVhQOhxb1Mc
https://youtu.be/MnW7DxsJth0