Why haven't terrorists exploded a nuclear weapon yet?

[JesuBungle]

I've been browsing the internet and have found sites where you can actually buy Uranium metal. Now I don't know if you need a specific kind, 235 or 238, but the basic ingredients in a fission bomb are Uranium and a case of TNT to implode around the Uranium. I'm sure there's a lot more to it, but what? Is 238 what they call enriched Uranium? Is this what's required? Just kinda confuses me if that's all there is to it. Thanks.

[Gilded]

Mostly, uranium you see on sale is depleted uranium (high 238 content). Natural uranium contains about 0.7% of the fissile type (which is isotope 235). Depleted contains even less. I must, however, admit I've seen small fuel grade uranium pellets on sale. These have a U-235 content of somewhere under 20%. Now, let's say someone would get hold of huge amounts of slightly enriched uranium. It would still need isotope separation to enrich it to weapons grade (about 85% or more), which is a process so difficult and expensive that even some small nations can't probably afford it. And the critical mass for uranium-235 is about 50kg so you need quite a bit of it too. I'm more concerned about terrorists getting hold of plutonium-239, which has a lower critical mass and is perhaps easier to use in an "improvised" nuclear device.

 

Summary: It is more likely that terrorists will get directly hold of a nuclear weapon than build one themselves.

[JesuBungle]

Thanks for the response. Yeah I'm thinkin they're kinda lazy like that, wouldn't do it the fun way. But I know for a fact those fools would blow one up the second they got their hands on it. Kinda scary.

[Genecks]

They were trying to build one, but it is too hard to create one. They need a larger workforce, and that workforce isn't going to appear soon.

 

- http://www.npr.org/templates/story/story.php?storyId=4857123

- http://www.theage.com.au/articles/2004/02/13/1076548223277.html?from=storyrhs

 

They would need a gigantic team of people with Ph.D's left and right.

[Neil9327]

To echo the previous response from Genacks it is very very difficult to produce a nuclear bomb that will explode in a nuclear fashion. I had a long conversation about this with an ex-nuclear weapon scientist who spent his entire career on the UK nuclear and thermonuclear bomb programmes, and his points can be summed up as follows:

 

1. To create the first "Trinity" bomb in 1945, the Americans had to spend billions of dollars, and have access to brilliant scientific minds such as Robert Oppenheimer.

The average Al-Qaeda terrorist network does not have access to either of these.

 

2. It is extremely difficult to engineer precision high explosives (RDX, TNT) to keep the uranium from deforming in shape while it is being compressed to the "critical mass" required for the neutron chain reaction to proceed.

 

3. Although there are a number of web sites that purport to show you how to make a nuclear bomb, these always miss a number of subtle but vital instructions - these are not in the public domain.

[SkepticLance]

As mentioned, the problem is obtaining enriched Uranium. As mined, Uranium metal is over 99% of the 238 isotope, which is essentially inert. Only the 235 isotope can explode in a bomb. You can make a bomb if you have, say 40% 235 in a block of uranium metal. If you can get it, it is real easy.

 

Just make two 50 kg cubes of Uranium metal, 40% 235. Drop one block onto the other. Boooomb!!!!

 

The problem is getting enough 235. Good luck!

[swansont]

Just make two 50 kg cubes of Uranium metal' date=' 40% 235. Drop one block onto the other. Boooomb!!!!

[/quote']

 

That description will get you a fizzle, I think. The engineering of "Little Boy" was a tad more involved than that.

[Neil9327]

That description will get you a fizzle, I think. The engineering of "Little Boy" was a tad more involved than that.

 

Exactly. If you exploded one piece of Uranium onto the other using military grade explosive, the uranium would indeed go supercritical for under a microsecond, cause the uranium to deform into a sausage shape because the engineering has small defects you were not aware of, and the nuclear reaction would stop.

 

At most, and this is a guess, you might double the explosive yield of the TNT.

[swansont]

Exactly. If you exploded one piece of Uranium onto the other using military grade explosive' date=' the uranium would indeed go supercritical for under a microsecond, cause the uranium to deform into a sausage shape because the engineering has small defects you were not aware of, and the nuclear reaction would stop.

[/quote']

 

Plus it has a tendency to blow itself apart.

[DV8 2XL]

The other thing that makes me laugh about the terrorist n-bomb boogie-man is the size of a crude device. These things would have to be huge. The small Davy Crockett size warheads have an incredible amount of engineering to fit in such a small package,

[JesuBungle]

The other thing that makes me laugh about the terrorist n-bomb boogie-man is the size of a crude device. These things would have to be huge. The small Davy Crockett size warheads have an incredible amount of engineering to fit in such a small package,

 

That's what the Ryder truck was invented for lol.

[padren]

With Plutonium it appeared all too easy to create a chain reaction in this case

 

http://en.wikipedia.org/wiki/Louis_Slotin

 

which was barely averted.

 

It does sound like the process of refining the radioactive metals to weapons grade is pretty involved. Also, if you could just buy uranium online and have a nuclear arsenal, Iran wouldn't be going to all the trouble it is. If Iran is only slowly developing weapons, then it would be much slower for a loose network of terrorists.

[swansont]

With Plutonium it appeared all too easy to create a chain reaction in this case

 

http://en.wikipedia.org/wiki/Louis_Slotin

 

which was barely averted.

 

It does sound like the process of refining the radioactive metals to weapons grade is pretty involved. Also' date=' if you could just buy uranium online and have a nuclear arsenal, Iran wouldn't be going to all the trouble it is. If Iran is only slowly developing weapons, then it would be much slower for a loose network of terrorists.[/quote']

 

The hard part was obtaining the plutonium and machining it into the hemispheres. And also the beryllium — nasty stuff to machine. The chain reaction wasn't averted, which is why Slotin died. But a chain reaction is not the equivalent of a bomb, as shown by the many nuclear reactors in operation over the years. And that incident.

[insane_alien]

yeah, just search criticality accident. loads of instances where runaway chain reacions were initiated but none were huge explosions, or even tiny ones. just lots of heat and particle radiation.

[SkepticLance]

"Exactly. If you exploded one piece of Uranium onto the other using military grade explosive, the uranium would indeed go supercritical for under a microsecond, cause the uranium to deform into a sausage shape because the engineering has small defects you were not aware of, and the nuclear reaction would stop."

 

Actually my recipe for a bomb will work. This is not a secret. It was published in Scientific American. The big problem is getting hold of 40% U235, which is almost impossible unless you have enormous resources. The WWII bombs used against Japan were enormous because of the lack of purity in the Uranium.

 

50kg U235 + 50 kg U235 = Big Bang!

 

However, the big bang will still be a lot less than, say, Hiroshima, since this is a pretty unsophisticated bomb. It would still take out a number of city blocks.

[Neil9327]

"Exactly. If you exploded one piece of Uranium onto the other using military grade explosive' date=' the uranium would indeed go supercritical for under a microsecond, cause the uranium to deform into a sausage shape because the engineering has small defects you were not aware of, and the nuclear reaction would stop."[/i']

 

Actually my recipe for a bomb will work. This is not a secret. It was published in Scientific American. The big problem is getting hold of 40% U235, which is almost impossible unless you have enormous resources. The WWII bombs used against Japan were enormous because of the lack of purity in the Uranium.

 

50kg U235 + 50 kg U235 = Big Bang!

 

However, the big bang will still be a lot less than, say, Hiroshima, since this is a pretty unsophisticated bomb. It would still take out a number of city blocks.

 

 

Who said it would work? If it was anyone other than a scientist who works on the bomb itself and therefore has access to top secret information I referred to earlier I would doubt their view.

 

Is your article online? Although I have to sayafter reading it I expect I would not be able to "disprove" that it could work because I am not that type of scientist.

[swansont]

Actually my recipe for a bomb will work.

 

...

 

50kg U235 + 50 kg U235 = Big Bang!

 

 

Simply reiterating your claim does not constitute proof/evidence. I second Neil's call for a link to the article.

[DV8 2XL]

There is a good deal more than slapping two chunks of highly enriched uranium together to make a super-critical assembly. The technical problems are an order of magnitude greater for an implosion device. Acquiring the material is also non-trivial and unlikely to escape notice or at the very least to acquire without leaving a trail. There is no entity outside of a State that could carry out such a project.

 

In the end terrorists are about leveraging a small amount of force to do a maximum amount of damage to demonstrate to the target population that they are vulnerable to attack from unexpected avenues.

 

Nuclear weapons on the other hand elicit fear through the threat of action because the effect of an attack or its location are unknown. Witness the fact that despite decades of effort by military planners all over the world, no one has yet tabled a credible first-use doctrine for this weapon that does not involve responding to a dire threat.

 

I am not yet convinced that the security situation in civil aviation has changed sufficiently (nor will it ever) to made another 9/11 attack impossible. Nor am I convinced that there are not other systemic vulnerabilities out there that some imaginative terrorist could exploit; but nuclear weapons are very low on that list.

[swansont]

There is a good deal more than slapping two chunks of highly enriched uranium together to make a super-critical assembly.

 

 

To make a supercritical assembly that will do what you want it to, as in a reactor or a bomb, yes. But just to make it go supercritical is not nearly as difficult.

[DV8 2XL]

Oh, picky, picky - you know what I mean

[ecoli]

I'm more worried about a terrorist organization raiding a nuclear waste facility and creating a dirty bomb, rather then a true nuclear bomb. It's cheaper, but still very deadly.

[DV8 2XL]

Na, to start off with high level waste is even less fun to play with than refined Pu. Second it's not that easy to make a device that will reliably aerosol the product over a wide area. Recall that this was seriously looked into during the Manhattan Project as an alternative to making the bomb. thirdly look at just how much of the stuff would be required to make such a thing effective - you can't run around with several hundred kg of used fuel core, assuming you got your hands on it in the first place, without drawing a lot of attention.

 

This is a non issue. Like I said above, you can get a lot more bang for your buck without the trouble of handling radioactive material.

[ecoli]

Na' date=' to start off with high level waste is even less fun to play with than refined Pu. Second it's not that easy to make a device that will reliably aerosol the product over a wide area. Recall that this was seriously looked into during the Manhattan Project as an alternative to making the bomb. thirdly look at just how much of the stuff would be required to make such a thing effective - you can't run around with several hundred kg of used fuel core,

 

You don't really need a lot of the stuff to make it effective. If you've ever been to New York city, or other densly populated areas, you should know that you don't need a wide area to injure a lot of people. Ever seen Times Sqare during New years?

 

assuming you got your hands on it in the first place, without drawing a lot of attention.

 

Nah, terrorists could concievably get the stuff from countries from the former soviet union. They are poor countries, and don't have the resources to protect nuclear wastes properly or could benefit from people just buying it off the black market.

[DV8 2XL]

So what do we have? A used fuel bundle made of zercaloy filled with mostly UO3 perhaps. To start off with you can't get near those things without soaking up a lethal dose of radiation, and they are hot with plain old heat to boot. Now what cover it with some C4 and set it off - chunks over what? Half a block? To hurt someone they would have to pick it up an keep it in their hands. The fact is you do need a lot of the stuff and it needs to be in a fine powder to do much harm and doing this is just too hard to make it attractive to any terrorist.

 

The West is full of big fat high-value targets that any well trained commando (because that's what the 9/11 strike force was) can make a bloody mess of with less fuss and bother than trying to smuggle in enough hot nuclear waste to contaminate a few streets in New York. We have got to wake-up and realise that we are not dealing with a threat from a handful of religious fanatics - this is true asymmetric warfare carried out by military or military trained operatives that have the resources, the logistical infrastructure, and the strategic planing behind them to make them a very efficient and deadly enemy. When they choose to strike they will do so to produce the maxium economic and social impact and kill as many people as they can. Nuclear is just not worth the trouble for this sort of force.

[[Tycho?]]

I think dirty bombs would be useful as psychological weapon, not so much a practical one. The bomb used to disperse the radioactive material would have to be powerful enough to spread it over a decent area. But a powerful bomb would just kill everyone nearby with the shock wave, then cause everyone else to run away, away from the radiation. Getting any kind of nuclear material in sizable quantities is extremely difficult, any terrorist orginization would find it far more efficient to just make a whole bunch of easy to build conventional bombs if they wanted to cause death and descrution.

 

But hearing that a radioactive weapon went off in some city would cause a panic, which is really the whole point of terrorism. But it wouldn't be a high death toll attack.