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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. Th

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.

icepat 3y ago
> Arguably it's the refining that's by far the most difficult process I think a large part of what makes it difficult is not the logistics, or even the refinement process. It's the other states looking over and thinking "these guys are making atom bombs", then putting a stop to it. Much like the Iranian attempt where the US injected a worm into the centrifuges that caused them to spin themselves to death.
- akiselev 3y ago
  That kind of dramatic industrial espionage just isn’t very common outside of fiction. Uranium enrichment really is that difficult due to the precision required to build gaseous centrifuges and the nasty hydrofluoric acid chemistry involved. ITAR and other restrictions on sale of advanced machinery has much more effect than espionage - the latter is more likely to spread the technology like with Dr Khan and Pakistan/North Korea On top of that, uranium is naturally 99.3% is non-fissile so you need tons of yellowcake to produce a small amount of weapons grade uranium, which requires crazy amount of power for the centrifuges.
  - icepat 3y ago
    > That kind of dramatic industrial espionage just isn’t very common outside of fiction. I was making specific reference to Stuxnet, and Operation Merlin. There's been several cases of this happening, so I'd say it's hardly fictional.
    - akiselev 3y ago
      I didn’t say it was fictional, I said it wasn’t very common outside of fiction.
  - deleted 3y ago
    [deleted]
- aliyfarah 3y ago
  The effects of the stuxnet virus is highly overrated. Within a few months they were replaced with a new generation of centrifuges.
bluGill 3y ago
Iran and North Korea have managed to figure it out. Note that the concern/news around Iran is their ability to make fissionable material, and not their ability to build a bomb if they have that material. The principals behind the bomb are (particularly the WWII bombs) are not that difficult to figure out. You can find pictures and diagrams with a simple google search. Even in WWII the hard part was getting material, not the design itself. Making fissionable material is also conceptually easy, but the process is tricky to do without killing yourself. Still Iran has figured it out from publicly available sources (and a lot of smart people). (as the other reply points out, the process is also leaves signs that other nations are likely to pick up on) edit: I'm not sure if Iran actually has made a working bomb, but the general consensus is they have the ability. If they don't have one it is only because between diplomatic pressure and sabotage they haven't got that far yet - absent of those two they would.
Robotbeat 3y ago
Yup. A gun-type fission bomb is very straightforward if you have access to U235. 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”

icepat 3y ago

> Arguably it's the refining that's by far the most difficult process I think a large part of what makes it difficult is not the logistics, or even the refinement process. It's the other states looking over and thinking "these guys are making atom bombs", then putting a stop to it. Much like the Iranian attempt where the US injected a worm into the centrifuges that caused them to spin themselves to death.

akiselev 3y ago
That kind of dramatic industrial espionage just isn’t very common outside of fiction. Uranium enrichment really is that difficult due to the precision required to build gaseous centrifuges and the nasty hydrofluoric acid chemistry involved. ITAR and other restrictions on sale of advanced machinery has much more effect than espionage - the latter is more likely to spread the technology like with Dr Khan and Pakistan/North Korea On top of that, uranium is naturally 99.3% is non-fissile so you need tons of yellowcake to produce a small amount of weapons grade uranium, which requires crazy amount of power for the centrifuges.
- icepat 3y ago
  > That kind of dramatic industrial espionage just isn’t very common outside of fiction. I was making specific reference to Stuxnet, and Operation Merlin. There's been several cases of this happening, so I'd say it's hardly fictional.
  - akiselev 3y ago
    I didn’t say it was fictional, I said it wasn’t very common outside of fiction.
- deleted 3y ago
  [deleted]
aliyfarah 3y ago
The effects of the stuxnet virus is highly overrated. Within a few months they were replaced with a new generation of centrifuges.

bluGill 3y ago

Iran and North Korea have managed to figure it out. Note that the concern/news around Iran is their ability to make fissionable material, and not their ability to build a bomb if they have that material. The principals behind the bomb are (particularly the WWII bombs) are not that difficult to figure out. You can find pictures and diagrams with a simple google search. Even in WWII the hard part was getting material, not the design itself. Making fissionable material is also conceptually easy, but the process is tricky to do without killing yourself. Still Iran has figured it out from publicly available sources (and a lot of smart people). (as the other reply points out, the process is also leaves signs that other nations are likely to pick up on) edit: I'm not sure if Iran actually has made a working bomb, but the general consensus is they have the ability. If they don't have one it is only because between diplomatic pressure and sabotage they haven't got that far yet - absent of those two they would.

Robotbeat 3y ago

Yup. A gun-type fission bomb is very straightforward if you have access to U235. 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”