71–80 of 100 posts
Earlier quoted context omitted.
As the other commenter says - North Korea isn't connected to the internet in any meaningful way so it's impossible to cyber sabotage their gas centrifuges remotely. Without the correct type of uranium, you can't build an a-bomb.
> Without the correct type of uranium, you can't build an a-bomb. Unless you have some plutonium.
I don't buy it. The crucial detail to buy the story is that Jim Frank told Dobson and Selden the truth: They were pulled aside by a senior researcher, Jim Frank. "Jim said, 'I bet you guys want to know how it turned out,'" Dobson recalls. "We said yes. And he told us that if it had been constructed, it would have made a pretty impressive bang." How impressive, they wanted to know. "On the same order of magnitude as H…
I buy it. I believe it's fairly well understood that designing a theoretical atom bomb that probably works isn't "difficult", the difficulty is building it. The logistics, and procuring the materials, that's very very hard. Also note, they did not cover refining the fissile material as part of their process, it was assumed that they had that. Arguably it's the refining that's by far the most difficult process.
Like fission WILL happen, the question is yield. Is it going to fizzle or will a large fraction of the fuel be burned up?
They talk about how to encourage the latter in the paper:
“The most important feature of the assembly times calculated in subsection (6) above is that they are more than 10 times the total fission chain reaction time. This means that it is essential for the fissile material to be neutron free during the assembly or the reaction will take place prematurely. If the fissile material is neutron free, then it is necessary to "turn on” neutrons to initiate the chain reaction at the desired time. This is the role of the so-called initiator”
Earlier quoted context omitted.
Can't they all -- except the production of plutonium in a reactor -- be made with upscaled garage tech? Uranium isotope separation can be done with lasers, for example, instead of the masses of Zippe centrifuges that used to be required (or the absolutely enormous air diffusion plants and calutrons the Manhattan Project used). If that's true, then the question becomes "how to produce a compact, cheap plutonium breedi…
But how does one get enough uranium to produce enough enriched uranium to reach critical mass? My guess you have to start with hundreds of kg:s.
that's not energy efficient and takes a long time, but it's relatively easy access.
https://www.epj-n.org/articles/epjn/pdf/2016/01/epjn150059.p...
~100g uranium / 117kg adsorbent material / month
a warhead needs about 25kg (enriched) uranium.
so 2,5 months with ~11,2tons of adsorbent material spread over a few square miles of sea should give you the needed 25kg. That still needs to be enriched, but once in operation a system like this generates about 125kg uranium/year. (if you need more or faster just scale the system, plenty of space within the 12 mile zone)
I wonder if the next step - designing a thermonuclear device given an A-bomb - has also been carried out? How the Teller-Ulam design works has been public for a long time...
And then there's the theoretical possibility of designing a thermonuclear device without the A-bomb part. I remember skimming through a paper from someone from CERN about it; https://arxiv.org/pdf/physics/0510071.pdf is the guy, but I'm not sure that's the exact paper.
There is a reddit where people discuss technical details about nuclear weapons design, do simulations: /r/nuclearweapons The funny thing is that 99% of public domain info regarding nuclear weapons design comes from US released documents. For Russia/China warheads we basically have no documents, and even exterior pictures are extremely rare.
In case of Russia there's a new factor in that those weapons might not even be operable anymore.
Earlier quoted context omitted.
> Without the correct type of uranium, you can't build an a-bomb. Unless you have some plutonium.
Pu-239 comes from uranium. It’s not a naturally occurring element.
Earlier quoted context omitted.
For those interested, Restricted Data is a fascinating book in this vein.
The blog they referred to and the book you mentioned are both by the same author :)
Why is everyone in this thread so cagey about revealing information? Is it on a need-to-know basis?
I don't buy it. The crucial detail to buy the story is that Jim Frank told Dobson and Selden the truth: They were pulled aside by a senior researcher, Jim Frank. "Jim said, 'I bet you guys want to know how it turned out,'" Dobson recalls. "We said yes. And he told us that if it had been constructed, it would have made a pretty impressive bang." How impressive, they wanted to know. "On the same order of magnitude as H…
Therefore it was not necessarily in violation of any rules to tell them the outcome after they had finished their project.