Assessing the Threat of Nuclear Terrorism
Given the nonstop coverage of everything terrorism-related over the last six years, it's amazing that we had to wait until November 2007 for someone to write this article. Katherine Shrader of the AP explores the feasibility of a terrorist detonating a so-called "suitcase nuke" in a major city. The bottomline:
Moreover, such a device would apparently be incredibly difficult and expensive to make and would, at best, only be operable for a period of months (eventually the radiation would fry the circuitry).
Shrader also makes a couple of other important points:
Now obviously we have to take all such threats seriously, no matter how improbable, but it's hard to come away from this article not feeling that the threat of nuclear terrorism has been greatly overstated in the media and in our political discourse. Put simply, it would be exceedingly difficult for a terrorist group to acquire, smuggle in, and then successfully detonate a nuclear device in the United States. And the much-hyped "suitcase nuke" scenario is likely fiction.
We can't make informed decisions about our foreign policy and anti-terrorism policies unless we have an accurate understanding of the risks we face. While I applaud Shrader and the AP for producing this article, I wonder why it took six years for someone to write it. It seems like it would have been particularly helpful, for instance, during the period from mid 2002 to early 2003 when our leaders were all warning us that if we didn't invade Iraq, "the smoking gun could come in the form of a mushroom cloud."
Members of Congress have warned about the dangers of suitcase nuclear weapons. Hollywood has made television shows and movies about them. Even the Federal Emergency Management Agency has alerted Americans to a threat — information the White House includes on its Web site.According to officials cited in the article, it's not clear whether suitcase-sized nuclear weapons have ever existed. Apparently, the U.S. at one time produced a device that could be carried in a large backpack (and required two people to detonate), but they've all been destroyed. And the Russians were long rumored to have created such a device, but no one has ever seen one.
But government experts and intelligence officials say such a threat gets vastly more attention than it deserves. These officials said a true suitcase nuke would be highly complex to produce, require significant upkeep and cost a small fortune.
Counterproliferation authorities do not completely rule out the possibility that these portable devices once existed. But they do not think the threat remains.
Moreover, such a device would apparently be incredibly difficult and expensive to make and would, at best, only be operable for a period of months (eventually the radiation would fry the circuitry).
Shrader also makes a couple of other important points:
Nuclear devices are either plutonium, which comes from reprocessing the nuclear material from reactors, or uranium, which comes from gradually enriching that naturally found element.Later in the piece, another expert suggests that the most *plausible* scenario involves a very sophisticated terrorist creating an "SUV-sized" improvised device with stolen uranium.
[Vahid Majidi, the assistant director of the FBI's Weapons of Mass Destruction Directorate] says it would take about 22 pounds of plutonium or 130 pounds of uranium to create a nuclear detonation. Both would require explosives to set off the blast, but significantly more for the uranium.
Although uranium is considered easier for terrorists to obtain, it would be too heavy for one person to lug around in a suitcase.
Plutonium, he notes, would require the cooperation of a state with a plutonium reprocessing program. It seems highly unlikely that a country would knowingly cooperate with terrorists because the device would bear the chemical fingerprints of that government. "I don't think any nation is willing to participate in this type of activity," Majidi said.
That means the fissile material probably would have to be stolen. "It is very difficult for that much material to walk away," he added.
Now obviously we have to take all such threats seriously, no matter how improbable, but it's hard to come away from this article not feeling that the threat of nuclear terrorism has been greatly overstated in the media and in our political discourse. Put simply, it would be exceedingly difficult for a terrorist group to acquire, smuggle in, and then successfully detonate a nuclear device in the United States. And the much-hyped "suitcase nuke" scenario is likely fiction.
We can't make informed decisions about our foreign policy and anti-terrorism policies unless we have an accurate understanding of the risks we face. While I applaud Shrader and the AP for producing this article, I wonder why it took six years for someone to write it. It seems like it would have been particularly helpful, for instance, during the period from mid 2002 to early 2003 when our leaders were all warning us that if we didn't invade Iraq, "the smoking gun could come in the form of a mushroom cloud."
posted by A.L. at 2:05 PM
15 Comments:
I have personally had custody, and been responsible for the safe handling and storage, of certain nuclear weapons of a particular type. They were small, but far too large to be placed in a suitcase, and far too heavy to be handled by one or two men. They had a yield of about ten kilotons, roughly that of the weapons used at Hiroshima and Nagasaki.
One of them could readily be smuggled into the U.S. in a bale of marijuana.
Just refreshed my memory from 35 years ago. The warheads in question were 13.75 inches in diameter and 25.3 inches length, weighed 170 pounds, and had a yield of 10 kilotons. Over 500 of them were produced.
"Little Boy" (Hiroshima) was 15KT; "Fat Man" (Nagasaki) was about 20 KT.
Neutral,
I don't know if you know the answer to this, but I'm genuinely curious. How hard is it to detonate a bomb of the type/size you're talking about? Easy? Hard?
And how advanced a weapon are we talking about? Is it something a fledging nuclear power (like Noko or someday Iran) could construct?
The point of my post (at least primarily) wasn't to a political point, but to actually get some accurate sense of what the risk is.
It seems that the risk analysis has three major parts:
1) how easy is it to obtain the weapon? Would only an advance nuclear power be able to produce it? Or could a country with a young program?
2) how easy would it be to smuggle the weapon into the U.S.? Is it small? Does it remain operable for a long time?
3) how easy would it be to detonate the bomb? Does it require technical know-how or skill? Does it require additional explosives?
My impression is that when taking all of these factors into account, the odds of an al Qaeda terrorist cell being able to carry out a nuclear attack on a U.S. city are pretty remote.
But maybe I'm wrong. What do you think?
People who think about this sort of thing professionally are most concerned about one arriving in a shipping container of which- still- only about 5% are checked.
Suitcase nukes are more figments of the imagination of novelists like Tom Clancy and screenwriters than a real threat. That's because a container ship arriving into the port of Baltimore is about as visually interesting as watching paint dry.
The real and immediate threats will be more localized. The Bushies have been crowing about the disappearance of al Qaeda in Iraq and point to that as a good thing. It's been about a year now since (I believe it was) the BBC was reporting that Iraqi refugees in Syria were claiming that al Qaeda
were flooding out with them in droves and disappearing into the night once reaching Syria.
Those guys are going to start showing up here, there and everywhere.
A.L.--
I'll take a whack at your questions from a moderately well-informed layman's perspective:
1) how easy is it to obtain the weapon? Would only an advance nuclear power be able to produce it? Or could a country with a young program?
There are two parts to making a bomb:
a) Producing the fissile material. You get what's called "highly enriched uranium" (HEU) by centrifuging or other gas-diffusion technologies. They are industrially intensive and relatively easy to detect. You produce Pu-239 by "breeding" it--you place U-238 in a reactor (which provides a neutron source), then you extract the Pu-239 using a chemical process called PUREX. My (limited) understanding of the PUREX process is that it is considerably less industrially intensive than HEU production, but you have to have a reactor or the waste products from a breeder reactor.
All in all, acquiring fissile material is extremely difficult, unless it can be stolen, bought on the black market, or otherwise extracted from obsolete nuclear weapons.
b) Constructing the bomb. A simple bomb requires precision machining (which is well within the reach of a terrorist organization), moderately sophisticated knowledge of shaped explosive charges, and some hard-but-possible-to-acquire electronic sequencers to control the detonation of the shaped charge. There are no insurmountable obstacles to the construction of a bomb by a terrorist group.
Note that construction of high-yield bombs is considerably more difficult. There are "boosting" technologies that can considerably increase the yield of a fission device from 5-15 KT up into the 50ish KT range. These require careful bomb maintenance (because the tritium in the boosters decays and produces neutron absorbers that can poison the reaction) and very high technology. Beyond that, of course, are themonuclear bombs, which are quite sophisticated. So a terrorist is unlikely to produce a nuke above 15 KT. That's the size of the bomb that was used against Hiroshima. Not something you'd like going off in mid-town Manhattan.
2) how easy would it be to smuggle the weapon into the U.S.? Is it small? Does it remain operable for a long time?
A plutonium "implosion" device is a sphere of plutonium that's baseball-to-grapefruit-sized, so the device with all of its Pu-239, plastic explosives, timers, neutron reflectors, and casing would be (and this is a serious SWAG) washing-machine sized and weigh less than 500 pounds. A U-235 bomb is more likely to be a "gun" configuration, where one slug of U-235 gets fired into another one. Such a device is indeed SUV-sized at least, which makes it harder to smuggle.
During their construction and the production of fissile material, bombs can be detected through the use of "sniffer" aircraft that can detect incredibly small amounts of fission products that drift away from the construction facility. However, once a bomb is buttoned-up, the only way to detect it is through the neutrons that it emits, which are quite easily shielded using lead. Bottom line: If the bomb is in a shipping crate, you would only find it if you were dealing with dumb terrorists.
As for how operable it would remain, this was an area where the AP article kinda screwed the pooch. Yes, electronics don't do well close to neutron sources. However, assuming that somebody receives and arms the bomb near the target, you simply keep the fissile material and the electronics separated from one another until you're ready to arm the bomb.
Again, boosted fission devices require lots of maintenance and are probably beyond the competence of a terrorist. Not so a crude fission device.
3) how easy would it be to detonate the bomb? Does it require technical know-how or skill? Does it require additional explosives?
Constructing a bomb is moderately difficult. Arming a bomb requires training but is pretty easy to do. Detonating it is the same as detonating any other kind of explosive. Yes, additional high explosives are needed, but nothing more exotic than C-4, Semtex, or RDX, all of which are readily available on the black market. But once you've got the bomb built, you set a timer or push a button. The high explosives go off in a very precisely timed pattern, they compress the core (or fire a slug) to achieve supercriticality, and the core fissions.
Bottom line: if terrorists can get 25-30 lbs. of Plutonium or 130 lbs. of HEU, they can probably construct, transport, and detonate a bomb.
Looking at european terrorist events, it is much, much more likely that the next terrorist event in the US will be non-nuclear and will be carried out by native US citizens.
Our counter-terrorist community has told us clearly, testified before congress, that we are going to experience further events. It is a matter of when, not if--they say.
While we can not predict the form of event, the american people seem to delight in petrifying themselves with all the possible ways an event could take place. We suffer through an orgy of "what-ifs" and "it could happen". Aided and abetted by those who seek to gain or maintain political power through imposition of widespread fear, suspicion and hatred.
To me, the question is not to predict the nature of the next event. We have people who are dealing with that, and how to prevent it. Rather, the american people should be discussing whether they want to endure the terrorist events that are certainly coming as americans, or do we wish to fundamentally change who we are--or rather, who we have been. Are we so sheepish that we want to turn america into a surveillance state in violation of its own founding principles and constitution, or will we live life with our traditional freedoms intact, and simply bear the brunt of the events that experts are telling us are inevitable.
Complete safety is an illusion. It has always been an illusion, and always will be. Government cannot guarantee saftey and security--but it can guarantee liberty. All it has to do is follow the law. It's that simple.
A.L., just about everything Radicalmoderate said is consistent with my understanding. The particular weapon I was familiar with was a plutonium implosion device, and the mechanism for detonating it was incredibly complex and sophisticated. I think it is way beyond the realm of possibility that anything like it could be constructed by any non-governmental group. I am extremely confident that none of these (U.S.) weapons is at risk of falling into unauthorized hands. The weapons system is no longer operational, and I assume these warheads were disposed of in some way. I am far less sure about comparable weapons in the Soviet Union. I can tell you that if I were to come into possession of one, fully intact, I would have no idea how to detonate it--I only knew how to do so with the particular system that was designed to go with it, and which was external to the weapon itself.
The US produced some number of nuclear artillery shells, some of which weighed under a hundred pounds. I'm not familiar with how they were to be detonated, and I don't know how they were disposed of. Again, I suspect the Soviets had comparable devices.
I see two possible threats. The first I don't think is very likely at all (although we can only imagine the consequences, particularly the psychological and economic ones). That would be an intact, sophisticated weapon delivered to an Al Qaeda-like group, complete with instructions, by a nuclear power. Even if Pakistan were to fall to radicals, or if Iran were to develop its own, I have serious doubt that they would be crazy enough to do this, simply because of the consequence of getting caught. (I don't think getting it into the US would be much of a problem.)
A more likely event, I think, would be a crude "dirty" device which would not result in a nuclear detonation but would disperse radioactive material over a large area (lower Manhattan, say) and render it uninhabitable for centuries. Unfortunately, I don't think it's too much of a problem to put together something of this kind.
Just as a footnote, in about 1961 I was told by an American officer, in the course of a lecture to about 100 of us, about a US nuclear weapon that was designed to be the size and shape of a fire hydrant. The funny thing is, although I was about 20 years old at the time, I thought it was bullshit when I heard it and I still do. I think it was a sort of throwaway line by a guy who wanted us to think we were on the cutting edge of inside knowledge.
Casual--
To me, the question is not to predict the nature of the next event. We have people who are dealing with that, and how to prevent it. Rather, the american people should be discussing whether they want to endure the terrorist events that are certainly coming as americans, or do we wish to fundamentally change who we are--or rather, who we have been.
Yup, that's the question. But the sad fact is that the facts on the ground have changed. The kind of attack you describe--conventional explosives, producing tens of casualties and virtually no economic damage--has been possible for hundreds of years and can indeed be absorbed by the American people. The ability to mount and execute a sophisticated mass-casualty operation is a new phenomenon, though.
Look at the risk-reward ratio for the terrorist. With small attacks, he gets [moderate probability of success] * [tens of casualties] = [fairly low per capita risk to the population].
However, when the terrorist attempts a mass-casualty attack, he gets: [maybe a tenth the probability of success] * [thousands of times as many casualties] = [hundreds of times the per-capita risk to the population]. Furthermore, it's a well-understood phenomenon for individuals to grossly over-estimate their increased risk, so the perceived increase in risk is much greater than the actual risk. It's a winner for a rich terrorist group to devote some non-trivial amount of its resources to the big-deal attack.
Furthermore, the economic impacts of a big attack scale vastly better than those of a small attack. The Bali, Madrid, and London bombings had little if any discernable economic impact--certainly well under a billion dollars. 9/11 cost hundreds of billions of dollars in direct effects and caused the 2000 recession to last an extra six months to a year. That's well over a trillion dollars in impact, at least a factor of 10,000 greater.
Remember, actuarially, people die in recessions. You can measure slight decreases in life expectancy during a recession. (Suicide is a big chunk of this and, oddly, transportation accidents rise a bit. I don't have data on infant mortality, but I'll bet it ticks up a bit, too.) Over a population of 300 million, those changes can result in thousands of additional deaths.
Sadly, terrorism works. It forces necessary changes in the behavior of the population being attacked. It is a great tragedy when our way of life is degraded, however marginally, because of these assholes. But it is a far greater tragedy when thousands of people die.
The trick is to change as little as prudent in response to attack. In the US (and the West in general), we're all searching for a new equilibrium, where we trade off a certain amount of freedom for some marginal reduction in threat.
This has to be a serious discussion. Denying that the threat hasn't increased and holding the line on all civil liberties is as silly as acceding to a new police state in exchange for only a modest threat reduction.
The proper response lies somewhere in the middle. We get to decide what that response is. We can only do that when the risk of attack is assessed--and perceived--correctly.
One point of disagreement with Radicalmoderate.
The tricky part about detonating the implosion device I knew about was insuring that all of the high explosive surrounding the plutonium ball detonate at precisely the same instant. The explosive sphere, roughly the size of a medicine ball, was covered with detonators, each of which was connected by electrical wiring to a triggering device. The requirement for simultaneous detonation was so exacting that the device initiating the electrical impulse to the detonators had to account for the differing lengths of electrical cable running to the different detonators. If the timing was not correct to the nanosecond, the result would be a high-explosive detonation that would propel the damaged, undetonated plutonium sphere some distance. A very unpleasant consequence, but not a nuclear detonation.
A couple of add-ons to Neutral:
There are several design goals for military nukes that increase the sophistication of the device, but that don't exist for terrorists:
1) Command and control is an overriding requirement. US nukes literally can't be detonated without proper authorization. Obviously not a goal for terrorists.
2) Military nukes have to be incredibly easy to arm and deploy in a matter of minutes. Terrorists can jury-rig whatever they need at their leisure.
3) Modern nukes have a facility called (and I'm not making this up) "dial-a-yield," which allows the explosive yield to range anywhere from 10 to 475 KT, depending on the target and the amount of collateral damage desired. Terrorists obviously just want the biggest bang they can get (which isn't very big by nuke standards, but is huge by the standards of conventional explosives).
4) Miniaturization is big deal for the military, since they're going to deliver warheads by ICBMs with limited payload capacities. Electronics therefore have to be small, highly reliable, and capable of more sophisticated implosion regimes. Terrorists need something that will fit in a shipping crate or a panel truck.
One additional correction to my previous post: I realize that I left the impression that implosion devices are just about as easy to build as gun devices. My understanding is that the technology is considerably more difficult (although the "fat man" nuke used on Nagasaki was an implosion device, so the technology isn't that much more sophisticated). Furthermore, use of Pu-239 requires an implosion device or the device will pre-detonate and fizzle. Similarly, implosion is harder to achieve the bigger the fissile core is, so HEU bombs are more likely to be gun devices, which are much larger.
This all actually has an implication for the terrorist. A small amount of Pu-239 is easier to acquire than the larger amount of HEU. However, an HEU gun bomb is much bigger. Even in a shipping crate, size is not kind to your friendly neighborhood terrorist. Big bombs are harder to shield and transport than small bombs, but small bombs are harder to make.
Any idea of the relative cost of plutonium versus HEU?
Enlightened--
FWIW, I found this in a random Wikipedia entry on the British nuclear weapons program:
The cost of HEU to the Royal Air Force was (at 1958-9 prices) £19,200 per kg, with plutonium priced at £143,000 per kg.
Presumably, these costs don't completely reflect the sunk costs of a uranium enrichment plant or a PUREX plant for plutonium. Also, note that the supply of U-235 is practically unlimited (although it needs hideously costly refining and enrichment), while the supply of Pu-239 is limited by how much of it is bred from U-238 in nuclear reactors.
Not a very satisying answer--sorry.
There still leaves the obvious possibility of a "normal" sized nuke loaded into a container arriving at any of the large sea ports. Back to early discussions post 9-11 and need to beef up incoming inspections. The idea of putting an Arabic company in charge of NY port inspections is bizarre unless there is either (a) confidence it could never happen or (b) some Machiavellian plan to actually encourage it to happen.
I think the threat of the "Arabic company" being in charge was grotesquely overstated, but understandable in the way that ethnic profiling is understandable.
I agree that it's possible to go nuts trying to imagine what form the next attack will take. One can play an interesting parlor game speculating about truly horrible events that could be brought about quite easily, particularly if the perps were suicidal. All things considered I think it's almost miraculous that it hasn't happened yet, and I really can't account for it.
My limited understanding of biological weaponry is that it is not an easy thing for amateurs to bring to bear. My nearly-as-limited understanding of chemical weaponry is much less optimistic.
If I were an Al Qaeda madman, I would...oh, never mind.
Andy says:
When I visited the atomic bomb museum at Sandia labs in New Mexico they had a small nuke on display called Davy Crockett. Not much bigger than a distorted basketball.
Do a google search on Davy Crockett nuclear and you can find more. It weighed well less than 100 pounds. I don't think
any armed Davy Crocketts exist now.
I don't know if this contradicts anything above, but it is an interesting fact that these things did exist, and thus are possible.
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