I was reading a book about terrorists and they were saying about terror groups wanting nuclear weapons.
They said the main drawback was enriching the urainium and a delivery system. But then they said unlike a nation that needs a plane or missile to deliever the nuke a terror group could get a large truck and park it then leave and be hundreds of miles away before it goes off.
So I was wondering would large a nuke (let’s say a crude nuke the kind the terrorist would be able to have) would be?
I read about the hydrogen bomb the Soviets made and it was so big (it was the largest nuke ever) that it couldn’t be delivered by any airplane or missile and was just for show.
The Tsar Bomba was delivered by the biggest plane the Soviets had at the time, modified to carry it.
In any event, a terrorist bomb isn’t likely to be a true nuclear bomb. It’s more likely to be a so-called “dirty bomb”, where the explosion scatters radioactive material over the area, making it toxic for humans in the same way that fallout from Chernobyl has denied that area to humans.
A true nuclear bomb would probably be deliverable in a large truck. Our ability to miniaturize nukes came from extensive testing, which isn’t available to terrorists. So they would build one that was more likely to work at the expense of size, using known principles to build it.
Surprisingly, there’s actually been a bit of research on the subject.
Lawrence Livermore conducted the “Nth Country Experiment” in 1964, as described in this Bulletin of the Atomic Scientists article, to test the ability of “physicists…no prior weapons experience, to develop a working nuclear weapon design using only unclassified information, and with basic computational and technical support.”
They apparently were indeed able to design a functional (although it was never actually built) implosion-type fission device, and although many of the design details were (and are) classified, it was reportedly small enough to fit on a plane. Which isn’t that helpful, really—you could squeeze pretty large things onto aircraft, even back then.
John Aristotle Phillips was a Princeton undergraduate who designed an atomic weapon, which was apparently an implosion device, and the FBI confiscated his term paper and a mockup of the device. However, Freeman Dyson claims that the design wasn’t functional.
Of course, a gun-type nuke would be easier, although less impressive, to design and build. I seem to recall someone here once mentioning a magazine (Omni?) article with a theoretical gun design largely featuring a long tube sunk into a dozen-odd feet of concrete, with the Uranium bullet being accelerated mostly by gravity. (I don’t remember the details for certain—and even if I did, I don’t know if that would actually work)
Some gun-type weapons actually built by nuclear powers might be of some interest, for comparison—South Africa’s first nuclear weapons were said to weigh about 2000 lbs, and IIRC, an unbuilt US gun-type from the 1950s would have weighed half that.
I’ve never troubled myself to read the whole thing, but an article in The Progressive from 1979 was subject to a case about prior restraint and as a result is rather famous, so that might be what you’re thinking of.
The only nuclear bomb that terrorists could easily build would be a gun-type and from things I have been reading in the Atlantic, they would need about 150lbs of weapons-grade uranium. The design is basically on wikipedia and while it is extremely inefficient, even a 1KT fizzle in a downtown major metropolitan area could potentially kill thousands and render that area unusable for years. Since such a weapon would likely be in a truck or a trailer or something, it would also kick up a whole bunch of fallout.
If the terrorists could put their hands on very highly enriched U235, they could make a useful gun bomb. You could use gravity, but why bother? Little Boy was powered by cordite. The machining of the uranium parts would be tough, and it might not work as well as Little Boy, but it would work well enough.
The trick is getting that much enriched U235.
Plutonium is much easier to get hold of, but you have to have a really good implosion design to make it do more than fizzle.
But why bother trying to make it all yourself. Pakistan has the bomb, and Iran is close. I don’t think the Iranians want to give their technology to just anyone; they may hate the US but they are smart.
It’s the Pakistanis I worry about, somebody wanting money for U235 or someone converted to radicalism. It’s the Pakistans we have to worry about; states that don’t have enough sense to keep nukes out of the hands of dangerous people.
But what am I talking about? Pakistan is our friend. It’s Iran that’s our enemy. Clearly, then, it’s safe for Pakistan to have the bomb, but not safe for Iran.
I’m not in favor of Iran having a nuke, and I don’t excuse their hatred of the US. The country is dominated by a bunch of fear-mongering radicals with little sense and even less judgment. But so is Pakistan, in many respects. And we know they have the bomb.
Short answer for more or less Hiroshima-power device built by engineers with some clue about what they’re trying to do, but no actual weapons experience:
Fit in an SUV? Maybe.
Fit in a mid-size U-Haul rental truck? Almost certainly.
Fit in an 18-wheeler? No sweat.
Keep in mind, though, that North Korea enjoyed the benefit of being a state actor, having an extensive development program, and on-site enrichment - and their attempt fizzled. To the best of my knowledge, the first ‘initial’ fizzle in the world - every other country’s first detonation went as planned. I agree with Airman Doors - it’s far more likely for a terrorist group to build a dirty bomb than for them to build a proper fission device.
To get the full destructive force of a nuclear weapon it needs to be detonated well above ground. However, IMO, the amount of physical disctruction/death would be secondary in a terrorist war. 9/11 showed that a handfull of terrorists could do 1/2 trillion dollars of damage to the economy and attack the seat of military power (almost succeeding in attacking the seat of political power). This was done in a couple of hours at almost no cost.
Applying the same tactics to 5 major cities would cause economic chaos and destroy the concept of large cities as a place to live or work.
If it’s using gravity to assemble the critical mass, it won’t work. It’s too slow.
Once you achieve criticality the assembly will explode. If you assemble the parts too slowly then the explosion will occur before they reach their optimal configuration and you’ll get a fizzle – a tiny blast that blows the device apart before most of the uranium/plutonium has a chance to react.
A gravity gun bomb will not work, as others have said. It’s documented that Little Boy used a gun capable of accelerating the “bullet” to a velocity equivalent to the muzzle velocity of a large-caliber naval gun. In fact, they brought on Navy personnel to help them design and construct the thing.
Bit of trivia: at first, they thought they needed a massive, long gun barrel to do this, something that couldn’t be delivered by air. That was based on standard formulas for barrel length and thickness for a given muzzle velocity and cordite propellant. Then someone said “Wait, that’s for a gun you’re going to re-use!” :smack: They recalculated for a single-use gun and came up with a long but relatively lightweight gun called “Thin Man” (and the implosion bomb was “Fat Man”). Later testing with U235 showed that the muzzle velocity could be lower, and the barrel was shortened, thus “Little Boy”.
Which brings us back to the gravity gun. We know it won’t work. Manhattan Project scientists calculated this out, and therefore felt safe testing U235 reactivity with a gravity apparatus they called the “guillotine”.
Perhaps this is an opinion rather than a fact, but based on what I’ve read about Pakistani work in atomic bombs, I would conclude that Islamic fundamentalist terrorists would get a bomb from that “source” rather than bother making one themselves.
Another opinion: we once worried about “lost” plutonium being stolen to be made into a nuke by a mad scientist/mad dictator/nutcase/terrorist. I think most analysts would agree that the dangers are a) someone will walk off with a bomb from a disarrayed former Soviet state, b) someone will do the same thing from a smaller “nuke” state with poor safety controls or c) a nuke state (or someone within it) will build a bomb for the highest bidder. It’s (b) that really worries me.
Slight correction—from what I’ve read, Thin Man was originally designed to use Plutonium, not Uranium; they switched to the latter when it was determined that the muzzle velocity required with the Plutonium bullet would have to be impractically high (meaning a working weapon would be undeliverable by the aircraft of the time), otherwise it’d fizzle.
But… nobody that I’m aware of (save maybe S. Africa) actually tested a gun-type weapon.
The US didn’t, because we were sure that it would work. That’s why the Gadget tested in the Trinity test was a prototype of Fat Man, a plutonium implosion bomb used on Nagasaki.
The bomb dropped on Hiroshima wasn’t even tested prior to use, because there’s so much (relatively) slop in the design, that they weren’t worried about it not working.
Terrorists would surely try to make a gun-type weapon, assuming they could get enough U-235 enriched.
Hmmm. I agree with you that they concluded a plutonium gun bomb was impractical. Whether or not they decided this early on, or later, I do not remember. My interpretation of the whole project is that they looked at both materials all during development. They also looked at both reaction mechanisms all during development.
Initially, this led to a disturbing impasse. The gun bomb was easy to do, but X division (the theoretical people) concluded that plutonium was too reactive for it. A Pu gun bomb would “fizzle”, that is, it would blow apart before sufficient reaction had occurred. This is hardly a fizzle in the same sense that a firecracker fizzles out!
On the other hand, the theorists predicted that implosion would work with Pu, but nobody could get a symmetric implosion to work!
To add to these frustrations, the scientists already knew that U235 would be incredibly difficult to isolate, while Pu would be relatively easy to make. Nobody had ever succeeded in isolating more than microscopic quantities of a pure isotope of an element. In comparison, the scientists were sure they could make as much plutonium as they wanted in a nuclear reactor; all they needed was time.
The two real breakthroughs of the Manhattan Project were implosion and U235 separation.
My understanding is that Pu is a bitch to work with, and doesn’t make the best nukes. Very soon after Fat Man, the US started doing experiments with improved implosion techniques and with U235/Pu mixtures. We reduced the size of a fission nuke to fit into a big artillery shell, which reminds me of the joke about the atomic hand grenade: they gave up on it because it had a blast radius of 300 feet, but a soldier could only throw it 150 feet!
I think that the “No actual weapons experience” sieve of engineering talent is a false premise. There are a fairly large number of former weapons engineers in the world, and they come from the usual broad range of philosophical, religious, and nationalistic backgrounds. The number with the exact experience might be quite small, but is it certainly not zero.
There are probably intact components for nuclear designs in many places in the world, and scientists and engineers who built them. Obtaining the fissile material is a big hurdle, but it is one that has already been jumped, and black market bombs are not an entirely unbelievable prospect.
When you shut down a nation’s weapons design programs, the talent doesn’t evaporate. Some of the folks who were trying to build bombs were doing it for reasons that are not altered by a change in citizenship.
