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How easy is it to build a nuclear bomb?

Arcade22

Philosopher
Arcade22
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Well how hard is it? I have some knowledge about particle physics and related things but i have no practical knowledge about hard it would be. Let's discard the missile.

What things would you need? How easy would it be for people to discover the project? I mean you see the US and the Soviets having thousands upon thousands of nuclear weapons but then you see a country like north korea struggle to achieve just a little fizzle...
 
Its not that hard. The hardest part is getting the fissionable material.
 
Arcade22 said:
Well how hard is it? I have some knowledge about particle physics and related things but i have no practical knowledge about hard it would be. Let's discard the missile.

What things would you need? How easy would it be for people to discover the project? I mean you see the US and the Soviets having thousands upon thousands of nuclear weapons but then you see a country like north korea struggle to achieve just a little fizzle...
Click to expand...

Once you have the fissionable material it takes explosive charges and a way to slam them together. The real issue is two fold:

1. Do you want to get radiation poisoning?
2. Keeping the masses apart enough so you don't have a sub critical event prior to slamming them together.

ETA: very hard to detect, smuggling the material is very dangerous but if you don'r care about dying, it would be like smuggling anything else of that size. You still have to keep the masses sepearted, so two or three smuggling events.
 
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Isn't it possible to build a simple weapon from dropping one just under critical mass onto another from a sufficient height? Far from efficient but it would that still be a nuclear explosion?
 
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dtugg said:
Its not that hard. The hardest part is getting the fissionable material.
Click to expand...
Exactly. A simple fission weapon is reasonably easy to construct. Fusion or boosted fission weapons are more difficult.
Once you've obtained sufficient material the assembly is reasonably straightforward. You'd need to carefully machine the fissile material into the correct form, depending on whether you're building an implosion or gun-barrel design, and then build a suitable explosive charge/rocket system to rapidly convert the material from non-critical to critical shapes.
The process is likely to be dangerous to those carrying it out unless precautions are taken; Uranium is radioactive, Plutonium is radioactive and highly toxic.
 
dtugg said:
Its not that hard. The hardest part is getting the fissionable material.
Click to expand...

Ah yes. Where do states like NK get their material from? How hard is it to "enrich" the material so much that it's actually usable in a weapon? Is it something that one could do in a garage at home or is a large industry required?

Dancing David said:
Once you have the fissionable material it takes explosive charges and a way to slam them together. The real issue is two fold:

1. Do you want to get radiation poisoning?
Click to expand...

As long as one is able to finish the bomb and blow it up I'd guess the amount of radiation poisoning one is affected by is unimportant. How dangerous is to be around the fissionable material before the explosion?

2. Keeping the masses apart enough so you don't have a sub critical event prior to slamming them together.
Click to expand...

like this?
 
Arcade22 said:
Ah yes. Where do states like NK get their material from? How hard is it to "enrich" the material so much that it's actually usable in a weapon? Is it something that one could do in a garage at home or is a large industry required?
Click to expand...

Pretty much all nuclear weapons use plutonium 239. It is made in a nuclear reactor and somehow separated from the other material (don't ask me how they do this, I dunno). This is most certainly not something that an individual could do in his garage. You can also make a nuclear bomb using uranium 235. But it is very hard to enrich from natural uranium in the necessary quantities. The entire Manhattan project only made enough for one bomb.
 
The hardest part is getting the U235. It has to be separated from the non-radioactive U238. The good news is that U238 is not being well guarded. You can order it on the internet. You can also pay people at Shinkolobwe to mine it for you. It's one of the richest sources of uranium in the world and it's entirely unguarded.

The hard part is that you need several hundred tons of uranium in order to get enough U235. And then you need a factory about the size of a college campus to separate it. Both centrifuge and screen methods require massive machines.

So, good luck with that.

ETA: You're probably better off scraping the cadmium out of used computer parts and trying to feed it to your landlord. I assume this is all about your landlord, right?
 
Depends on how many kilotonne your yield need to be.

10K thereabout (hiroshima) is quite well documented and easy to do, from cannon type to sphere type.

Now multi stage yield is a tad bit more complicated (i think above 50kt would need to check that), and as faras I know not well documented above 3rd stage, as it involve special material or layering of different material for the reflection of neutron. Much more difficult.
 
If you do happen to have a bit of U235 a simple gun type device is not that hard at all.

It's the implosion type devices that require a lot of technical precision.
 
nvidiot said:
Isn't it possible to build a simple weapon from dropping one just under critical mass onto another from a sufficient height? Far from efficient but it would that still be a nuclear explosion?
Click to expand...

One of the sci-fi mags, or maybe Omni or something, published a description around 1980, IIRC. You basically built a 4-story vertical cannon, with one hemisphere at the bottom, the other at the top, and bombed the top one down to slam into the bottom.

Would it work? I don't know. For all I know it is disinformation to release plans that don't work, on the off chance someone deliberately tried to do it. That would be a good idea, now that I think about it.

Also, watch for "suspicious people" buying 3-story (with basement) brownstones.
 
catsmate1 said:
Exactly. A simple fission weapon is reasonably easy to construct. Fusion or boosted fission weapons are more difficult.
Once you've obtained sufficient material the assembly is reasonably straightforward. You'd need to carefully machine the fissile material into the correct form, depending on whether you're building an implosion or gun-barrel design, and then build a suitable explosive charge/rocket system to rapidly convert the material from non-critical to critical shapes.
The process is likely to be dangerous to those carrying it out unless precautions are taken; Uranium is radioactive, Plutonium is radioactive and highly toxic.
Click to expand...


Hmm. What is the correct shape? How much of fissile material is needed? All the whilst avoiding predetonation. What is the relationship between the required velocity of the bullit/implosion, the rate of spontanious fission , the ambient neutron level and the likelyhood of predetonation? On a related note, how can we ensure that the chain reaction starts at the moment of maximum supercriticallit?. What device is needed to achieve that? What is the required precission in symmetry for an implosion type of device? How do we achieve such a level of symmetry?

Methinks making a nuclear weapon is quite a bit more difficult than that is popularly believed. :)
 
Isn't the amount needed variable with the speed of impact? That implosion concept is used to allow smaller amounts. So the trade off is, lots more precision in an implosion device, vs lots less Plutonium. In Tom Clancy's novel, they used lens grinding machines, and it still fizzled. Not many lens grinding machines in home shops.
 
NutCracker said:
Hmm. What is the correct shape? How much of fissile material is needed? All the whilst avoiding predetonation. What is the relationship between the required velocity of the bullit/implosion, the rate of spontanious fission , the ambient neutron level and the likelyhood of predetonation? On a related note, how can we ensure that the chain reaction starts at the moment of maximum supercriticallit?. What device is needed to achieve that? What is the required precission in symmetry for an implosion type of device? How do we achieve such a level of symmetry?

Methinks making a nuclear weapon is quite a bit more difficult than that is popularly believed. :)
Click to expand...

All this stuff can be looked up in scientific literature.

One problem is already mentioned: One need to get enough fissionable material. For a Uranium bomb, that's pretty much the only stumbling block.

Plutonium is a different kettle. Much, much less fissionable material is needed, but machining Plutonium is tricky. It heats up, self-ignites easily and is nasty to workers. You would need experienced experts and the right tools to make an actual Pu nuke. Plutonium, if it end up in the wrong hands, is more likely to be used in a dirty bomb (non-nuclear explosion that spreads radioactive fallout).
 
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nvidiot said:
Isn't it possible to build a simple weapon from dropping one just under critical mass onto another from a sufficient height? Far from efficient but it would that still be a nuclear explosion?
Click to expand...

Pretty much, again if you don't care if you kill yourself, it is very easy. Explosives just help insure that sub critical events don't melt the fissible materials prior to the critical event.
 
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