Broken Arrows Before the Storm?

by John Holbo on July 17, 2005

Everyone else read Rick Perlstein’s Before the Storm months ago. But better late than never. OK, I just read about Ike’s famous military-industrial complex speech and Kennedy’s inauguration. And here’s a thing.

On January 19 [1961], the American nuclear program suffered its thirteenth “broken arrow” when a B-52 exploded in midair in Utah, luckily without any of the missiles armed; the fourteenth was ten days later when a B-52 flying a routine Strategic Air Command training mission out of Seymour-Johnson Air Force Base crashed near a North Carolina farm. The aircraft’s two nuclear bombs jettisoned and five of their six safety mechanisms were unlatched by the fall. (p. 101)

Is that as bad as it sounds? That is, did North Carolina almost blow up? Or would it just have been a (comparatively) minor matter of a serious radiation leak making some farmland uninhabitable for a period of centuries?

UPDATE: I had the date as 1960 but comments corrected me. It was my mistake, not Perlstein’s.



Arm 07.17.05 at 9:15 am

Unlikely that the bombs would have gone off; the core is a carefully machined sphere that relies on precise timing of the detonation explosives to go critical. Simply slamming into the ground wouldn’t do it.


Njorl 07.17.05 at 9:39 am

Even if armed, it is almost inconceivable that the firing triggers would engage in a sequence that would allow for a chain reaction. At worst, the bomb would be damaged, allowing the chunks of fissile material to come into close enough proximity to do some fizzling. Even that is unlikely. You’d need an impact strong enough to smash a bomb, but not strong enough to scatter the contents.


Brett Bellmore 07.17.05 at 9:50 am

Amusing; Even Bikini atoll probably isn’t going to be uninhabitable for “centuries”; Drop a nuke on a farm field, and if it doesn’t explode, you’ll be planting a crop there the next year.


John Holbo 07.17.05 at 10:06 am

Really? Bikini Atoll will be inhabitable within centuries? I had thought not. I suppose it was careless of me to write ‘centuries’ in this case, barring an actual explosion. Since, yes, you could at the very least just clear away the top soil. Sorry to get everyone into a panic.


Joshua W. Burton 07.17.05 at 10:10 am

The Goldsboro, NC event involved two enormous (multimegaton) weapons. The date was actually one year later, 24 Jan 1961, four days into Kennedy’s administration. They never found all of the U-238 blanket (the third stage in a fission-fusion-fission weapon), so they finally just bought an easement to stop anyone else from digging.

This was not the worst incident. Travis AFB in California was named for a general who was killed in 1950 a plane crash that actually detonated the (conventional) explosives of a disarmed weapon, killing dozens and destroying a barracks. In 1958 a weapon (nuclear capsule not installed) was dropped on some poor farmer’s HOUSE in South Carolina, where it exploded, leveling the house. And in 1966 four fully armed weapons were lost in a mid-air refueling crash over Palomares, Spain, two of them exploding conventionally and scattering nuclear material over acres of farmland.

“Uninhabitable for centuries” is a vast exaggeration. Point a Geiger counter at a brick building sometime.


Bertrand 07.17.05 at 10:12 am

Someone check up an Brett, please. That boy is too easily amused.


almostinfamous 07.17.05 at 10:15 am

Even Bikini atoll probably isn’t going to be uninhabitable for “centuries”
i thought that was because the majority of high-yield tests were conducted over the open water?

most nuclear bombs i think(i hope!!) are secure enough that they would only chain-react when the proper trigger is applied. the worst that could happen otherwise is an explosion of the conventional explosives that might scatter the uranium/plutonium over a relatively small area and contaminate the soil and water supply for a while.


almostinfamous 07.17.05 at 10:22 am

IOTW, it would be like purple rain, except instead of purple, you’d have plutonium. and instead of a lot of singing there would be lots of melanoma. i guess my analogy kinda falls apart there, doesnt it?


SusanC 07.17.05 at 10:42 am

People who are interested in this kind of thing might like to read Steve Bellovin’s notes on Permissive Action Links.


Arm 07.17.05 at 11:02 am

Note that PALs weren’t in general use until the 1970s, so that doesn’t apply to weapons before then.

On the general topic, remember that most nuclear weapons rely on a fission trigger, a plutonium/uranium core that sets off the larger bomb. These cores are usually sub-critical (i.e. below critical mass). They will not detonate by themselves. Instead, they rely on extremely precise conventional explosions to compress the subcritical mass down to a density where it becomes critical and starts a chain-reaction. Doing that by accident is almost impossible.


John Holbo 07.17.05 at 11:02 am

Thanks susanc. That link contains the following information, copiously footnoted to what appear to be formidably reliable sources. (The numbers are supposed to be superscripts. 10 to the -6 and all that.)

“Bombs are also engineered to fail gracefully. For example, the high-explosive shell is closely matched to the characteristics of the fissile materials in the pit; if anything but the exact proper detonation occurs, there should be no nuclear reaction. The design goal for the safety mechanisms is a probability of less than 10-6 that an accidental detonation at one point in the explosives surrounding the core can cause a detonation equivalent to more than four pounds of TNT, and the probability of an accidental nuclear detonation due to component malfunction be less than 10-9 for normal conditions, and 10-6 for abnormal conditions.

Advances in computers have permitted the use of three-dimensional models of bomb components. These have shown that earlier two-dimensional models were dangerously misleading. Apparently, the danger was greater than had been appreciated that an accidental explosion could cause dispersal of radioactive materials or even a nuclear yield.”

Of course, greater risk than these extremely low levels of risk might still be very very low risk. Still …


John Holbo 07.17.05 at 11:18 am

Sorry, I didn’t quote the punchline:

“In at least one incident, a nuclear weapon did come very close to accidental detonation. In 1961, a B-52 with two large warheads crashed near Goldsboro, North Carolina; the impact set off the conventional explosives in one of the bombs, and triggered all but one of the safety mechanisms in the other.”


paul 07.17.05 at 11:30 am

Try 10^6, for exponents, if using <sup> tags doesn’t give you what you want.


Joshua W. Burton 07.17.05 at 11:45 am

The world’s leading sleuth on these matters is a fellow named Chuck Hansen. Here is his summary of the Goldsboro incident.

Wikipedia has an exhaustive catalog of known incidents.


abb1 07.17.05 at 12:32 pm

There’s been a number of false alarm incidents as well.


eudoxis 07.17.05 at 1:08 pm

Most of the radioactive release in today’s nuclear weapons is from the second stage fusion reaction. The isotopes used for this reaction are stable, and, even if spread by an initial detonation device gone wrong, not harmful. Most detonation devices are built to explode a weapon in air, so are not designed for impact expolosion. There is still an amount of plutonium and uranium but it won’t spread in the way a dirty bomb is designed to spread radioactive materials. Perhaps I’m a bit cavalier about these risks. Naturally occuring uranium poses an actual danger in the form of radon with tens of thousands of deaths every year.


Brett Bellmore 07.17.05 at 4:27 pm

So if it crashes in somebody’s basement, you’d definately want to install a ventilation fan. ;)

Worst case, short of an actual detonation, would be the bomb breaking up on impact, and the fisile materials catching fire. (Both uranium and Plutonium burn quite well.) I don’t think that would make any place uninhabitable as such, but you’d have to dig up a fair amount of topsoil if it was a farm, and haul away that year’s crops


Doug Muir 07.17.05 at 4:52 pm

John, Bikini atoll has been safe for a while now.

“It is safe to walk on all of the islands… The Advisory Group reaffirmed: although the residual radioactivity on islands in Bikini Atoll is still higher than on other atolls in the Marshall islands, it is not hazardous to health at the levels measured. Indeed, there are many places in the world where people have been living for generations with higher levels of radioactivity from natural sources – such as the geological surroundings and the sun – than there is now on Bikini Atoll… By all internationally agreed scientific and medical criteria… the air, the land surface, the lagoon water and the drinking water are all safe. There is no radiological risk in visiting the lagoon or the islands. The nuclear weapon tests have left practically no cesium in marine life. The cesium deposited in the lagoon was dispersed in the ocean long ago.

“The main radiation risk would be from the food: eating locally grown produce, such as fruit, could add significant radioactivity to the body… Eating coconuts or breadfruit from Bikini Island occasionally would be no cause for concern. But eating many over a long period of time without having taken remedial measures might result in radiation doses higher than internationally agreed safety levels.”

That’s from the International Atomic Energy Agency’s report of 1998.

The Bikinians haven’t moved back yet, but that’s a sad and complicated story that no longer has anything to do with radioactivity.

Doug M.


Barry Freed 07.17.05 at 5:14 pm

Sure, plutonium’s pretty harmless stuff. Brett eats the stuff for breakfast, or didn’t you know he’s on the Silkwood diet?


Brett Bellmore 07.17.05 at 6:19 pm

Nah, I usually have squid ramen for breakfast, washed down with a diet Mt. Dew. Though who knows what’s really in the Dew… lol


Michael Mouse 07.18.05 at 6:52 am

I’m not terribly reassured by the risk of an accidental explosion being 10^6. A risk around 10^9 is considerably better. (To be precise: it’s about a thousand times better!)

At a very rough guesstimate, something of the order of 100,000 nukes have been produced. The USA has produced, at one time or another, somewhere around 75,000 (with a current stockpile is around 10-20,000 depending on who you believe). Rounding up to allow for Warsaw Pact and a handful elsewhere gives 100,000.

Taking the conservative position that the odds of accidental explosion are for the lifetime of the weapon (not, say, an annual risk figure), if you start with a chance of 10^6 per weapon, you’re actually looking at a 1 in 10 chance of one going up by mistake.


PersonFromPorlock 07.18.05 at 9:12 am

The 10^-6 figure is for weapons involved in accidents, not for weapons in existence. If your assumption was correct we would have seen many accidental nuclear yields by now.


Jake McGuire 07.18.05 at 2:59 pm

Worth pointing out that there are lots of different plutonium isotopes, and that the one you want to use in a bomb (Pu-239) is comparatively non-radioactive. Still nasty stuff, but not even remotely as nasty as the fission products that Chernobyl scattered across Europe, or what’s left after a nuclear explosion.

And you’d probably want to cart the topsoil away anyhow, to prevent someone from buying the farm and carting the soil away to extract the plutonium and use it in a nuclear bomb.


American Citizen 07.18.05 at 3:38 pm

I’m just amazed there were 14 “Broken Arrows” as of 1961. I thought the movie “Broken Arrow” was wildly far-fetched. The “Broken Arrow” part of it obviously isn’t (though the rest is).


Maynard Handley 07.18.05 at 3:59 pm

A good analogy is that a fusion weapon (and to a much lesser extent a plutonium fission weapon) is a lot more like a computer program than a standard mechanical device, by which I mean:
we are used to the fact that computer programs are brittle; things have to happen in an exact order and any deviation from expectation probably means the program won’t work, unlike something like a car or an airplane which degrades gracefully in the face of mechanical damage.

One way to see that this has to be true is to remember that the US is not the only country in the world. The Soviets and Chinese have surely also been flying and shipping these things around and all indications are that they are a lot more cavalier about safety than the US. Whatever problems resulted from their accidents, they certainly weren’t of the city-block-destroying, visible from space variety, and the soviets and chinese appear to have been able to keep them hidden. A few people probably died, but as a result of the conventional explosives, and much like as happens every year shipping conventional munitions.

On a secondary point, I’d like to ask all the people who made fun of Brett to consider just what they think they are doing for their cause. Brett and I may disagree on most political issues, but we are discussing issues of FACT here. How is a claim (even embedded in mockery) along the lines that Bikini is uninhabitable, when scientific evidence clearly says otherwise, any different from a claim that “global warming is unproven”.
Once you switch to a mode of rhetoric unanchored to facts and based purely on emotion and what you want the world to be, you’ve lost all credibility, and it doesn’t matter whether the issue you are pushing is left-wing or right-wing.
If you don’t like nuclear power, justify your dislike in real science and real numbers; don’t just make up shit to try to scare people.


paul staniland 07.18.05 at 9:38 pm

people interested in this kind of thing might want to check out Stanford political scientist Scott Sagan’s book “The Limits of Safety: Organizations, Accidents, and Nuclear Weapons” (Princeton, 1993)


James Wimberley 07.19.05 at 9:23 am

Bikini atoll was the site of successful nuclear explosions, where the fissile uranium and plutonium was mostly transformed into other elements and isotopes of them, many with short half-lives. A fizzle or a conventional explosion, with or without fire, would disperse the original elements. So the environmental and health hazards must be quite different. Plutonium at least is highly poisonous, an eternal chemical property independent of its radioactivity. The site of a non-explosive nuclear accident should perhaps be thought of as a major toxic waste spill. No, you would not want to live there.

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