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ARE SUITCASE BOMBS POSSIBLE?
Nuke Testing Dot EnviroWeb Dot Org ^ | updated May 18, 2002 | Carey Sublette

Posted on 03/04/2003 6:48:08 PM PST by doug from upland

Are Suitcase Bombs Possible?

By Carey Sublette

Last changed 18 May 2002


It is impossible to verify at the time of this writing whether nuclear devices sized to fit in side a suitcase were actually manufactured by the former Soviet Union, as alleged by Alexander Lebed in September 1997. It is certainly possibel to assess the technicial plausibility of such a claim and to provide a analysis of the likely characteristics of the weapons Lebed described.

A suitcase bomb with dimensions of 60 x 40 x 20 centimeters is by any standard a very compact nuclear weapon. Information is lacking on compact Soviet weapons, but a fair amount of information is available on compact US designs which provides a good basis for comparison.

The smallest possible bomb-like object would be a single critical mass of plutonium (or U-233) at maximum density under normal conditions. An unreflected spherical alpha-phase critical mass of Pu-239 weighs 10.5 kg and is 10.1 cm across.

A single critical mass cannot cause an explosion however since it does not cause fission multiplication, somewhat more than a critical mass is required for that. But it does not take much more than a single critical mass to cause significant explosions. As little an excess as 10% (1.1 critical masses) can produce explosions of 10-20 tons. This low yield seems trivial compared to weapons with yields in the kilotons or megatons, but it is actually far more dangerous than conventional explosives of equivalent yield due to the intense radiation emitted. A 20 ton fission explosion, for example, produces a very dangerous 500 rem radiation exposure at 400 meters from burst point, and a 100% lethal 1350 rem exposure at 300 meters. A yield of 10-20 tons is also equal to the yield of the lowest yield nuclear warhead ever deployed by the US -- the W-54 used in the Davy Crockett recoilless rifle.

A mere 1.2 critical masses can produce explosive yield of 100 tons, and 1.35 critical masses can reach 250 tons. At this point a nation with sophisticated weapons technology can employ fusion boosting to raise the yield well into the kiloton range without requiring additional fissile material.

The amount of fissile material that constitutes a "critical mass" varies with the material density and the type of neutron reflector present (if any). A high explosive implosion can compress fissile material to greater than normal density, thus reducing the critical mass. A neutron reflector reduces neutron loss and reduces the critical mass at a constant density. However generally speaking, adding explosives or neutron reflectors to a core adds considerably more mass to the whole system than it saves.

A limited exception to this is that a thin beryllium reflector (thickness no more than the core radius) can actually reduce the total mass of the system, although it increases its overall diameter. For beryllium thicknesses of a few centimeters, the radius of a plutonium core is reduced by 40-60% of the reflector thickness. Since the density difference between these materials is on the order of 10:1, substantial mass savings (a couple of kilograms) can be achieved. At some point though increasing the thickness of the reflector begins to add more mass than it saves since volume increases with the cube of the radius. This marks the point of minimum total mass for the reflector/core system.

A low yield minimum mass or minimum volume weapon would thus use an efficient fissile material (plutonium or U-233), a limited amount of high explosives (sufficient only to assembly the core, not to compress it to greater than normal density), and a thin beryllium reflector.

We can now try to estimated the absolute minimum possible mass for a bomb with a significant yield. Since the critical mass for alpha-phase plutonium is 10.5 kg, and an additional 20-30% of mass is needed to make a significant explosion, this implies 13 kg or so. A thin beryllium reflector can reduce this by a couple of kilograms, but the necessary high explosive, packaging, triggering system, etc. will add mass, so the true absolute minimum probably lies in the range of 11-15 kg (and is probably closer to 15 than 11).

This is probably a fair description of the W-54 Davy Crockett warhead. This warhead was the lightest ever deployed by the US, with a minimum mass of about 23 kg (it also came in heavier packages) and had yields ranging from 10 tons up to 1 Kt in various versions. The warhead was basically egg-shaped with the minor axis of 27.3 cm and a major axis of 40 cm. The test devices for this design fired in Hardtack Phase II (shots Hamilton and Humboldt on 15 October and 29 October 1958) weighed only 16 kg, impressively close to the minimum mass estimated above. These devices were 28 cm by 30 cm.


W-54 Davy Crockett (38 K)

The W-54 design probably approaches the minimum size for a spherical implosion device (the US has conducted tests of a 25.4 cm implosion systems however).

The W-54 nuclear package is certainly light enough by itself to be used in a "suitcase bomb" but the closest equivalent to such a device that US has ever deployed was a man-carried version called the Mk-54 SADM (Small Atomic Demolition Munition). This used a version of the W-54, but the whole package was much larger and heavier. It was a cylinder 40 cm by 60 cm, and weighed 68 kg (the actual warhead portion weighed only 27 kg). Although the Mk-54 SADM has itself been called a "suitcase bomb" it is more like a "steamer trunk" bomb, especially considering its weight.

Minimum mass and minimum volume are not the only design criteria of interest of course, since even 25.4 cm (10 inches) is rather thick even for a suitcase and is wider than the reported 20 cm thickness of Alexander Lebed's suitcase bomb. Another approach is to instead develop a minimum diameter or minimum thickness design.

Minimizing nuclear weapon diameters has been a subject of intense interest for developing nuclear artillery shells, since the largest field artillery is typically the 208 mm (8.2 inch) caliber, with 155 mm (6.1 inches) artillery being the workhorse. Nuclear artillery shell designs with diameters as small as 105 mm have been studied. Packaging a nuclear artillery shell in a suitcase is an obvious route for creating a compact man-portable device.

The US has developed several nuclear artillery shells in the 155 mm caliber. The only one to be deployed was the W-48 nuclear warhead developed by UCRL, packaged in the M-45 AFAP (artillery fired atomic projectile) shell. The W-48 nuclear warhead measured 86 cm (34") long and weighed 53.5-58 kg (118-128 lbs). Its yield was on the order of 70 to 100 tons (it was tested in the Hardtack II Tamalpais shot with a yield of 72 tons, predicted yield was 100-300 tons).

The smallest diameter US test device publicly known was the UCRL Swift device fired in the Redwing Yuma shot on 28 May 1956 . It had a 5" (12.7 cm) diameter, a length of 62.2 cm (24.5 inches) and weighed 43.5 kg (96 lb). The test had a yield of 190 tons, but was intended to be fusion boosted (and thus would probably have had a yield in the kiloton range) but its yield was insufficient to ignite the fusion reaction and it failed to boost in this test. This test may have been a predecessor to the W-48 design.

Later and lighter 155 mm designs were also developed -- the W74 (canceled early in development), and the W-82/XM-785 shell. The W82 had a yield of up to 2 kilotons and weighed 43 kg (95 lb), but included a number of sophisticated additional features within this weight. Since it was capable of being fielded with a "neutron bomb" (enhanced radiation) option, which is intrinsically more complex than a basic nuclear warhead, and was in addition rocket boosted, the actual minimum nuclear package was substantially lighter than the weight of the complete round. Its overall length was 86 cm (34").

It is reported that designs least as small as 105 mm (4.1 inches) are possible. A hypothetical 105 mm system developed for use in an artillery shell would be about 50 cm (20 inches) long and weigh around 20 kg.

Compact nuclear artillery shells (208 mm and under) are based on a design approach called linear implosion. The linear implosion concept is that an elongated (football shaped) lower density subcritical mass of material can be compressed and deformed into a critical higher density spherical configuration by embedding it in a cylinder of explosives which are initiated at each end. As the detonation progresses from each direction towards the middle, the fissile mass is squeezed into a supercritical shape. The Swift device is known to have been a linear implosion design.

It is quite likely, that should the suitcase bombs described by Lebed actually exist, that they would use this technology. It is clear that any of the 155 mm artillery shells, if shortened by omitting the non-essential conical ogive and fuze would fit diagonally in the package that Lebed describes, and the Swift device would fit easily. If the yield is as much as 10 kilotons, then the device would have to be fusion boosted.

A somewhat more sophisticated variation would extend the linear implosion concept to cylindrical implosion, in this case an oblate (squashed) spheroid, roughly discus-shaped, of plutonium would be embedded in a cylinder of high explosive which is initiated simultaneously around its perimeter. The cylindrically converging detonation would compress and deform the fissile mass into a sphere, that could be wider than the original thickness of the system. This type of design would make the flattest possible bomb design, perhaps as little as 5 cm. The only obvious application for such a device would be briefcase bomb, and would require a special development effort to create it.

See Section 4.2 of the Nuclear Weapons FAQ for more details.

Source of weapon and test details The Swords of Armageddon, by Chuck Hansen, Chuckelea Publishing, 1995.


TOPICS: Business/Economy; Culture/Society; Foreign Affairs; Government; Miscellaneous; News/Current Events
KEYWORDS: suitcasenuke; terrorists

1 posted on 03/04/2003 6:48:08 PM PST by doug from upland
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To: doug from upland
They are possible. It is also possible that you are Queen of the May.

Soviet suitcase bombs require Soviet-grade fissionables, and there isn't much of that around anymore because they had such a high degree of impurities. Those whose fissionables haven't been recooked in the past ten years will at best fizzle.

Hint, how many years ago did the USSR croak?

2 posted on 03/04/2003 7:04:43 PM PST by Thud
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To: Thud
I remember something about tritium detonators or switches or something that had to be refreshed every 6 months or the device would be worthless.
3 posted on 03/04/2003 7:19:23 PM PST by xrp
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To: doug from upland; Fusion; Hoplite
Stanby for some expert commentary. A fierce Chechneyen warrior named Baseyev is in possesion of several of these & is headed to Moscow traveling light. At least thats what I've been hearing for several months.
4 posted on 03/04/2003 7:22:50 PM PST by Archie Bunker on steroids
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To: Thud
Thanks for the info.
5 posted on 03/04/2003 7:23:09 PM PST by doug from upland (Bill and Hillary's first instinct is survival.....their second is to lie.)
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To: doug from upland
Go to the National Atomic Museum in Albuquerque NM and see for yourself. The have a nuclear bomb on display that was intended to be shot out of field artillery. This 1960's technology could fit into a suitcase. There's also a large black and white picture of this puppy going off. While you are there don't forget to climb up on the hydrogen bomb and ride it like Slim Pickens. Bring a cowboy hat.
6 posted on 03/04/2003 7:23:15 PM PST by Gary Boldwater
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To: doug from upland
Although the Mk-54 SADM has itself been called a "suitcase bomb" it is more like a "steamer trunk" bomb, especially considering its weight.

I have been arguing all along that what have been called "suitcase bombs" -- if such exist at all -- would most likely have to be more along the lines of "steamer trunk" sized. Even if the Soviets did manage to engineer something small enough to fit into a suitcase, the requirements for the physics package would require material so fresh that it would be basically useless for any terrorist who got hold of one. A "steamer trunk" sized device might actually be within the range of capability for a rogue state like Iraq or NK or Iran, however, and it would not have quite the challenging demands of maintaining the physics package that a true "suitcase bomb" would have. And a "suitcase bomb" could be transported by car or boat, which would be good enough for most terrorist operations.

7 posted on 03/04/2003 7:26:36 PM PST by Stefan Stackhouse
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To: xrp
True. Also, the plutonium in the weapon is only usable for about a decade after the date of initial manufacture (i.e., production in the reactor)--it gradually decays into americinum.
8 posted on 03/04/2003 7:26:58 PM PST by Poohbah (Beware the fury of a patient man -- John Dryden)
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To: doug from upland
What about satchel bombs?
9 posted on 03/04/2003 7:28:38 PM PST by Consort
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To: doug from upland
Here you go:

http://www.atomicmuseum.com/tour/cw3.cfm

Is it possible with todays technology? You decide.
10 posted on 03/04/2003 7:29:35 PM PST by Gary Boldwater
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To: doug from upland
Some scumbags took over airplanes and flew them into
WTC killing 3,000. Anything is possible.
Let's roll Now!!!!!
11 posted on 03/04/2003 7:36:41 PM PST by 2rightsleftcoast
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To: Gary Boldwater
Is it possible?

Yes.

Is it likely that such a device would remain in ready-for-issue condition this long after manufacture, if they indeed disappeared at the fall of the USSR?

Not really.

Would such a device make for a nasty radiation bomb, if nothing else?

Hell, yes!

12 posted on 03/04/2003 7:38:22 PM PST by Poohbah (Beware the fury of a patient man -- John Dryden)
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To: doug from upland
Piece of cake.

In 1966, we were "famiiarized" with the 155mm Atomic Munition. It was an artillery shell about 6 inches in diameter, 20 inches long, 200 lbs. Of that size and weight, about 80 lbs, 2 inches in diameter, and 4 inches in length were for "hardening," to make it strong enough to be shot out of the angry end of a 155mm howitzer.

Take away the hardening, and you have a 120 lbs, 4 inch by 16 inch fission weapon..... and that was late 1950s technology!

Look now for 92 lens implosion weapons, cup shaped pits, zippers and fission-fussion, about the size of a coffee, 60 pounds+/- in the 100-400 kiloton range! Nasty.
13 posted on 03/04/2003 7:42:35 PM PST by MindBender26 (.....and for more news as it happens...stay tuned to your local FReeper station....)
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To: Poohbah
Even worse if the warhead didn't go off or shatter (spreading radiation), it could leave a nasty dent or big scrape mark on the side of whatever it hit.
14 posted on 03/04/2003 7:43:07 PM PST by Gary Boldwater
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To: Poohbah
My point was that Soviet suitcase bombs were designed to operate with a particular grade of fissionable which is no longer available. Use of better quality fissionables would produce different results than the original Soviet designers anticipated.
15 posted on 03/04/2003 7:49:01 PM PST by Thud
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To: MindBender26
coffee can
16 posted on 03/04/2003 7:49:32 PM PST by MindBender26 (.....and for more news as it happens...stay tuned to your local FReeper station....)
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To: Poohbah
Whoa, the half-life of Pu-239 is about 25,000 years. The amount which will decay into U-235 (not americium - Pu-239 decays by alpha emission) is negligible over a ten-year period.

I would consider the possibility that the radiation field might cause a significant degradation of the electronics and the trigger.

If tritium is involved (half-life is about 12 years as I recall), then the decay over 10 years is very significant.

17 posted on 03/04/2003 7:55:48 PM PST by bagman
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To: Consort
What about satchel bombs?

I saw a "billfold bomb" one time in Mombasa, but it was so heavy, it tended to drop the wearer's trow.

18 posted on 03/04/2003 8:00:51 PM PST by ALASKA
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To: doug from upland
It's all here.

http://nuketesting.enviroweb.org/hew/Usa/Weapons/Allbombs.html
19 posted on 03/04/2003 8:00:54 PM PST by MindBender26 (.....and for more news as it happens...stay tuned to your local FReeper station....)
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To: xrp
I remember something about tritium detonators or switches or something that had to be refreshed every 6 months or the device would be worthless.

Building very small nukes is actually harder than making them a little bigger (they tend to fizzle instead of going off). Using tritium detonators makes it much easier to design a small bomb that will actually go off.

This fact has led several freepers to insist that tritium triggers MUST be used. That would be nice, but it is simply wishful thinking. Likewise, the "steamer trunk" comments about the size are also simply wishful thinking. The facts are that a small nuclear device CAN be built, and it can be built without a tritium trigger.

It would be a very high tech device beyond the capability of any Islamic nation. The Russians say they built some. Whether some are missing or not is in dispute.

Likewise, the ability to set one off even if you have it is questionable. Presumably the Russians had some sort of fail safe device even on these weapons, and not knowing the proper codes could make the weapons impossible to detonate.

Thud's comment about needing to recook the fissionable material is on the money, but the amount of time that can go by before needing to "refresh" the material will vary. Whether ten years is too long will depend on the specific materials used. In principle, a small bomb could be designed that would last even longer than this. The electronics will be affected by neutron emissions, and will need to be refurbished periodically as well.

All in all, the more time that goes by the more likely these weapons are to fail to detonate. However, insisting that they could not have been built in the first place, or that they need new triggers every six months, is simply wishful thinking.

20 posted on 03/04/2003 8:19:22 PM PST by EternalHope (France is with the terrorists.)
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To: bagman
You're forgetting the Pu-241 component, which decays into Americium-241 with a 13.2 year half-life. A 16-kg pit will have 80 grams of Pu-241 at manufacture, and 40 grams of Americium-241 at 13.2 years. Americium-241 is an intense emitter of alphas, gammas, and X-rays. Not the sort of thing you want in a bomb you're trying to hide from NEST!
21 posted on 03/04/2003 8:20:23 PM PST by Poohbah (Beware the fury of a patient man -- John Dryden)
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To: doug from upland

22 posted on 03/04/2003 8:21:23 PM PST by freepersup (And this expectation will not disappoint us.)
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To: doug from upland

23 posted on 03/04/2003 8:25:46 PM PST by freepersup (And this expectation will not disappoint us.)
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To: doug from upland
Our W-88 warhead is supposed to be the size of a basketball! This being said and not knowing what old Soviet technology is on the loose, I'd say it's possible but not very probable. These devices need lots of maintenace you know.
24 posted on 03/04/2003 8:36:44 PM PST by blastdad51
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To: Stefan Stackhouse
The "suitcase" nukes are of Russian manufacture, hence the small reported size.

I agree completely about the "steamer trunk" size requirement if a less developed nation is the source. However, Pakistan has successfully tested nukes that fit into missile warheads. I suspect these are smaller than "steamer trunks". The Pakistani design has reportedly been sold/given to several other muslim nations.

The Pakistani bombs are kept in a separated and disassembled state until they are ready to be used. That may be to protect the electronics, or because they need to use fresh tritium as a trigger (or both). (It could also be to keep a complete bomb from falling into the wrong hands.)
25 posted on 03/04/2003 8:47:13 PM PST by EternalHope (France is with the terrorists.)
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To: doug from upland

Do "backpack" nuclear weapons exist?

Yes, small atomic charges exist. They are very small. Several dozen kilos, thirty kilos, forty kilos. I spoke with people that made them, I saw them. The American specimens can be seen on the Internet, they can be seen on photographs, they can even be seen in the movies. I have never seen Russian analogies, I have only seen American ones, but Russian ones do exist, because I spoke with people who made them, and I believe these people, these people knew what they were talking about. And there was data published about it. ... Some was published in the newspaper of a town in the south of the Urals in a little paper, and it said there that the prominent achievement is that they have manufactured a miniature atomic charge. ... No one knows how many exist ... . Lebed mentioned that there's forty-eight, or a hundred and fifty, but no one knows for certain.


26 posted on 03/04/2003 8:49:52 PM PST by freepersup (And this expectation will not disappoint us.)
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To: freepersup
Alexei Yablokov

Former Science Advisor to Yeltsin, Yablokov testified before a subcommittee of the House National Security Committee in October, 1997 about the existence of unaccounted for "suitcase" nuclear weapons.

http://www.pbs.org/wgbh/pages/frontline/shows/russia/suitcase/comments.html
27 posted on 03/04/2003 8:52:51 PM PST by freepersup (And this expectation will not disappoint us.)
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To: doug from upland
http://www.pbs.org/wgbh/pages/frontline/shows/russia/suitcase/

Links to two short video clips of US military personnel demonstrating delivery of man portable SADM devices.
28 posted on 03/04/2003 8:57:57 PM PST by freepersup (And this expectation will not disappoint us.)
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To: bagman
Soviet weapons-grade fissionables had relatively much greater impurities, aka undesirable radioactive materials, in them than those of any other country with more than a few nukes. This greater proportion of impurities caused the fissionable triggers in Soviet nuclear weapons, including those of "suitcase" nukes, to have rather short shelf-lives - at most 10 years before they decayed into fizziles.

The Soviets instead constantly disassembled their nukes to remove and recook the weapons-grade fissionables in the triggers. It was cheaper for them to do that than to get the last few degrees of purity in creating those fissionables in the first place.

29 posted on 03/04/2003 10:41:19 PM PST by Thud
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