Posts Tagged ‘Accidents’

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Accidents and the bomb

Friday, April 18th, 2014

When I first heard that Eric Schlosser, the investigative journalist was writing a book on nuclear weapons accidents, I have to admit that I was pretty suspicious. I really enjoyed Fast Food Nation when it came out a decade ago. It was one of those books that never quite leaves you. The fact that the smell of McDonald’s French fries was deliberately engineered by food chemists to be maximally appealing, something I learned from Schlosser’s book, comes to mind whenever I smell any French fries. But nuclear weapons are not French fries. When writing about them, it is extremely easy to fall into either an exaggerated alarmism or a naïve acceptance of reassuring official accounts. In my own work, I’m always trying to sort out the truth of the matter, which is usually somewhere in between these two extremes.

Schlosser - Command and Control book

This is especially the case when talking about nuclear weapons accidents — the many times during the Cold War when nuclear weapons were subjected to potentially dangerous circumstances, such as being set on fire, being accidentally dropped from a bomber, crashing with a bomber, having the missile they were attached to explode, and so on. The alarmist accounts generally inflate the danger of the accidents achieving a nuclear yield; the official accounts usually dismiss such danger entirely. There are also often contradictory official accounts — sometimes even the people with clearances can’t agree on whether the weapons in question were “armed” (that is, had intact fissile pits in them), whether the chance of detonation was low or high, and so on. I’ve always been pretty wary about the topic myself for this reason. Sorting out the truth seemed like it would require a lot of work that I wasn’t interested in doing.

Well, I’m happy to report that in his new book, Command and Control: Nuclear Weapons, the Damascus Accident, and the Illusion of SafetySchlosser has done that work. I reviewed the book recently for Physics Today. You can read my PT review here, but the long and short of it is that I was really, really impressed with the book. And I’m not easily impressed by most works of nuclear weapons history, popular or academic. I’m not surprised it was a finalist for the Pulitzer Prize, either.

Titan II silo complex. There's a lot going on in one of these. This, and all of the other Titan II images in this post, are from Chuck Penson's wonderful, beautiful Titan II Handbook.

Titan II silo complex. There’s a lot going on in one of these. This, and all of the other Titan II images in this post, are from Chuck Penson’s wonderful, beautiful Titan II Handbook.

What I ask out of a new book is that it teach me something new — either novel facts or novel spins on things I already knew about. Schlosser’s book does both. He clearly did his homework when it came to doing the work, and it’s not really surprising it took him about a dissertation’s worth of time to write it. It’s not just a document dump of FOIA’d material, though. He really shines when contextualizing his new information, writing a very rich, synthetic history of nuclear weapons in the Cold War. So the new and the old are woven together in a really spectacular, unusually compelling fashion.

The book has two main threads. One is a very specific, moment-by-moment account of one accident. This is the so-called Damascus Accident, which is when a Titan II missile in Damascus, Arkansas, exploded in its silo in 1980, resulting in one fatality. It’s not one of the “standard” accidents one hears about, like the 1961 Goldsboro bomb, the 1958 Tybee bomb, the 1968 Thule crash, or the 1966 Palomares accident. But Schlosser’s journalist chops here really came through, as he tracked down a huge number of the people involved in the accident and used their memories, along with documentary records, to reconstruct exactly how one dropped spanner — itself just an apparently innocuous, everyday sort of mistake — could lead to such explosive outcomes.

The other thread is a more historical one, looking at the history of nuclear weapons and particular how the problem of command and control runs through it from the beginning. “Command and control” is one of those areas whose vastness I didn’t really appreciate until reading this book. Nominally it is just about making sure that you can use the weapons when you want to, but that also includes making sure that nobody is going to use the weapons when you don’t want them to, and that the weapons themselves aren’t going to do anything terrible accidentally. And this makes it mind-bogglingly complex. It gets into details about communication systems, weapons designs, delivery system designs, nuclear strategy, screening procedures, security procedures, accident avoidance, and so much more.

How do you service a Titan II? Very carefully. This is a RFHCO suit, required for being around the toxic fuel and oxidizer. Not the most comfortable of outfits. From Penson's Titan II Handbook.

How do you service a Titan II? Very carefully. This is a RFHCO suit, required for being around the toxic fuel and oxidizer. Not the most comfortable of outfits. From Penson’s Titan II Handbook.

Schlosser weaves this all together wonderfully. I found very few statements, technical or otherwise, that struck me as genuine outright errors.1 Of course, there are places where there can be differences of interpretation, but there always are. This is pretty good for any book of this length and scope — there are many academic books that I’ve read that had more technical errors than this one.

What I found really wonderful, though, is that Schlosser also managed to give a compelling explanation for the contradictory official accident accounts that I mentioned before. It’s so simple that I don’t know why it never occurred to me before: the people concerned with nuclear weapon safety were not the same people who were in charge of the weapons. That is, the engineers at Sandia who were charged with nuclear safety and surety were institutionally quite remote from the Air Force people who handled the weapons. The Air Force brass believed the weapons were safe and that to suggest otherwise was just civilian hogwash. The engineers who got into the guts of the weapons knew that it was a more complicated story. And they didn’t communicate well — sometimes by design. After awhile the Air Force stopped telling the Sandia engineers about all of the accidents, and so misinformation became rampant even within the classified system.

The fate of the world in a few punched holes. Penson: "Targeting information was stored on Mylar-backed punched paper tape. Though primitive by today's standards, punched paper tape will retain data decades longer than magnetic tapes or CDs. This tape is somewhat worse for wear from 20 years of museum use, but probably would still work."

The fate of the world in a few punched holes. Penson: “Targeting information was stored on Mylar-backed punched paper tape. Though primitive by today’s standards, punched paper tape will retain data decades longer than magnetic tapes or CDs. This tape is somewhat worse for wear from 20 years of museum use, but probably would still work.”

We usually talk about nuclear weapons safety as a question of whether they are “one-point safe.” That is, will the weapon have a chance of a nuclear yield if one point on the chemical explosives surrounding the fission pit detonated inadvertently? Most of the time the answer is no, of course not. Implosion requires a very high degree of detonation symmetry — that’s why it’s hard to make work. So a one-point detonation of the explosive lenses will produce a fizzle, spreading plutonium or uranium like a “dirty bomb” but not producing a supercritical chain reaction.

But some of the time, answer is, “well, maybe.” We usually think of implosions as complex affairs but some weapons only require two-point implosion to begin with. So now you’re no longer talking about the possibility that one out of 36 explosive lenses will go off; you’re talking about one out of two. This isn’t to say that such weapons aren’t one-point safe, just to point out that weapons design isn’t limited to the sorts of things present in the first implosion weapons.

But even this doesn’t really get at the real problem here. “One-point safe” is indeed an important part of the safety question, but not the only one. Consider, for example, what would happen if the firing signal was only a simple amount of DC electrical current. Now imagine that during a fire, the firing circuit board soldering melts and a short-circuit is formed between the batteries and the firing switch. Now the bomb is actually trying to truly set itself off as if it had been deliberately dropped — and full implosion, with nuclear yield, is totally possible.

The injector plate of a Titan II. I thought the somewhat abstract pattern of holes and corrosion on the recovered plate made for a beautiful image. The diagram at left shows you what you are looking at — this is where fuel and oxidizer would come together, propelling the missile.

The injector plate of a Titan II. I thought the somewhat abstract pattern of holes and corrosion on the recovered plate made for a beautiful image. The diagram at left shows you what you are looking at — this is where fuel and oxidizer would come together, propelling the missile.

How likely is this kind of electrically-activated nuke scenario? What the Sandia engineers discovered was that in some weapons it was really not implausible at all. Under the “abnormal environment” of a weapons accident (such as a crashing or burning B-52), all sorts of crazy things could happen with electronic circuits. And unless they were really carefully designed for the possibility of this kind of accident, they could arm themselves and fire themselves. Which is the kind of thing you’d expect an engineer who is deeply connected with the electrical technology of the bomb to conclude.

And of course, as Schlosser (and his engineer sources) point out — this kind of thing is only one small detail in the broad, broad question of nuclear safety. These systems are big, complex, and non-linear. And so much hinges on them working correctly.

The sociologist of science Donald MacKenzie has proposed (in a slightly different context — nuclear weapons accuracy, not safety) that a “certainty trough” exists with regards to complex questions of technological uncertainty. He draws it somewhat like this:2

MacKenzie's Certainty Trough

So this divides people into three groups. On the left are the people who actually build the technology and the knowledge. These people have reasonably high levels of uncertainty about the technology in question — they know the nuts and bolts of how it works and how it could go wrong. (I’ve added “confidence” as a label because I find it more straightforward than “uncertainty” at times.) They also know what kinds of failure situations are not likely as well. In the middle, you have people who are completely committed to the technology in question. These people aren’t completely divorced from solid knowledge about it, but they are just consumers of knowledge. They look at the final data, but they don’t really know how the data was made (and all of the uncertainty that gets screened out to make the final version of the data). They have very low uncertainty, and so very high confidence in the technology. At far right you have the people who are either total outsiders, or people who are totally committed to another approach. These have the highest levels of uncertainty and the lowest levels of confidence.

So if we were mapping Schlosser’s actors onto these categories, we’d have the Sandia engineers and other weapons scientists on the far left. They know what can go wrong, they know the limits of their knowledge. They also know which accident situations are outlandish. In the middle we have the military brass and even the military handlers of the weapons. They are committed to the weapons. They have data saying the weapons are safe — but they don’t know how the data was made, or how it was filtered. They think the weapons are totally safe and that anyone who suggests otherwise is just ignorant or foolish. And lastly, at far right, we have total outsiders (the activists, perhaps, or sometimes even politicians), or people who really are looking to amplify the uncertainty for their own purposes.

Titan II Launch Control Center, with the facilities console at center. From Penson.

Titan II Launch Control Center, with the facilities console at center. From Penson.

The disconnect between the far left group and the middle group is the one that disturbs me the most in Schlosser’s account. It also reflects what I’ve seen in online discussions of weapons accidents. People with a little bit of knowledge — e.g. they know about one-point safety, or they once handled nukes in the military — have very high confidence in the safety issues. But they don’t know enough to realize that under the hood, things are more complicated and have been, in the past at least, much more dangerous. Not, perhaps, as dangerous as some of the more alarmist, outsider, activist accounts have stressed. But dangerous enough to seriously concern people whose jobs it is to design the weapons — people who know about the nuts and bolts of them.

Anyway. Schlosser’s book is a great read, as well. Which it needs to be, because it is long. But it’s also segregable. Don’t care much of the details of the Damascus accident? You can skip those sections and still get a lot out of the book (even though the Damascus accident is really a perfect account of all of the little things that can go wrong with complex, non-linear systems). But part of that length is a copious amount of endnotes, which I applaud him and his publisher for including. For a book like this, you can’t skimp on the documentation, and Schlosser doesn’t. The only thing he did skimp on was illustration, which I — as a pretty visual guy — thought was too bad. So much of the Damascus story takes place inside of a Titan II silo, and while the inner flap of the cover did have a simplified illustration of one, I still felt like I didn’t really know what was happening where at times. (I wonder if this was a trade-off with the publisher in having so many notes and pages.)

Chuck Penson's Titan II Handbook, and one of its several amazing fold-out diagrams. Adorable pupper (Lyndon) for scale.

Chuck Penson’s Titan II Handbook, and one of its several amazing fold-out diagrams. Adorable pupper (Lyndon) included for scale.

Fortunately, there is a solution for this. If it were up to me, every copy of Schlosser’s book would be accompanied by a copy of Chuck Penson’s Titan II Handbook: A civilian’s guide to the most powerful ICBM America ever built. Penson’s book is a richly illustrated history of this particular missile, and contains lots of detailed photographs and accounts of daily life on a Titan II base (such as those seen above) It’s utterly fascinating and it gives so much visual life to what Schlosser describes. It also includes giant fold-out diagrams of the missiles themselves — the printing quality is really impressive all around. It includes fascinating technical details as well. For example, in the early days of the Titan II silos they had large motor-generators that constantly ran in case they needed to convert DC power into AC in the event of a failure of commercial power. Penson then notes that:

The motor-generator ran with a loud, monotonous high-pitched whine… noise in the [Launch Control Center] turned into a serious issue. Crew members complained of temporary hearing loss due not only the incessant buzz of the motor-generator, but also to the constant drone of the air conditions, fans and blowers in equipment. Eventually the Air Force covered the tile floor with carpeting, and acoustic batting was hung in the in the area of the stairway leading up to level 1 and down to level 3. … These changes made a tremendous improvement, but one that came too late for many of the crew, a significant number of whom now need hearing aids.

This kind of detail fits in perfectly with Schlosser’s approach to the facility, which itself seems strongly influenced by the sociologist Charles Perrow’s notion of “Normal Accidents.” That the devices in the facility would affect the hearing of the crew was certainly not something that anybody thought of ahead of time; it’s one of those little details that gets lost in the overall planning, but (at least for those who suffered the hearing loss) had real consequences. Ultimately this is the thesis of Schlosser’s book: that the infrastructure of nuclear command and control is much larger, much more complex, much more problematic than most people realize, and is one of those high-complexity, high-risk systems that human beings are notoriously pretty bad at managing.

If you’re the kind of person who geeks out on nuke history, both Schlosser’s and Penson’s books are must-reads, must-buys.

Notes
  1. The two biggest mistakes I noted, which I’ve told Schlosser about and may be fixed in the paperback, are that he misstates the size of the neutron initiator in the Fat Man bomb — he confuses the diameter for the radius — and he got the story of Szilard’s 1933 chain reaction work wrong, which lots of people do. Szilard’s patent is such a common source of misunderstanding even amongst scholars that I will be writing a blog post about it soon. Neither of these are terribly important to his argument or narrative. []
  2. Adapted from Donald MacKenzie, Inventing Accuracy: A Historical Sociology of Nuclear Missile Guidance (Cambridge, Mass.: MIT Press, 1990), figure 7.2. []
Meditations

Castle Bravo at 60

Friday, February 28th, 2014

Tomorrow, March 1, 2014, is the 60th anniversary of the Castle Bravo nuclear test. I’ve written about it several times before, but I figured a discussion of why Bravo matters was always welcome. Bravo was the first test of a deliverable hydrogen bomb by the United States, proving that you could not only make nuclear weapons that had explosive yields a thousand times more powerful than the Hiroshima bomb, but that you could make them in small-enough packages that they could fit onto airplanes. It is was what truly inaugurated the megaton age (more so than the first H-bomb test, Ivy Mike, which was explosively large but still in a bulky, experimental form). As a technical demonstration it would be historically important even if nothing else had happened.

One of the early Bravo fallout contours. Source.

One of the early Castle Bravo fallout contours showing accumulated doses. Source.

But nobody says something like that unless other things — terrible things — did happen. Two things went wrong. The first is that the bomb was even more explosive than the scientists thought it was going to be. Instead of 6 megatons of yield, it produced 15 megatons of yield, an error of 250%, which matters when you are talking about millions of tons of TNT. The technical error, in retrospect, reveals how grasping their knowledge still was: the bomb contained two isotopes of lithium in the fusion component of the design, and the designers assumed only one of them would be reactive, but they were wrong. The second problem is that the wind changed. Instead of carrying the copious radioactive fallout that such a weapon would produce over the open ocean, where it would be relatively harmless, it instead carried it over inhabited atolls in the Marshall Islands. This necessitated evacuation, long-term health monitoring, and produced terrible long-term health outcomes for many of the people on those islands.

If it had just been natives who were exposed, the Atomic Energy Commission might have been able to keep things hushed up for awhile — but it wasn’t. A Japanese fishing boat, ironically named the Fortunate Dragon, drifted into the fallout plume as well and returned home sick and with a cargo of radioactive tuna. One of the fishermen later died (whether that was because of the fallout exposure or because of the treatment regime is apparently still a controversial point). It became a major site of diplomatic incident between Japan, who resented once again having the distinction of having been irradiated by the United States, and this meant that Bravo became extremely public. Suddenly the United States was, for the first time, admitting it had the capability to make multi-megaton weapons. Suddenly it was having to release information about long-distance, long-term contamination. Suddenly fallout was in the public mind — and its popular culture manifestations (Godzilla, On the Beach) soon followed.

Map showing points (X) where contaminated fish were caught or where the sea was found to be unusually radioactive, following the Castle Bravo nuclear test.

Map showing points (X) where contaminated fish were caught or where the sea was found to be unusually radioactive, following the Castle Bravo nuclear test. This sort of thing gets public attention.

But it’s not just the public who started thinking about fallout differently. The Atomic Energy Commission wasn’t new to the idea of fallout — they had measured the plume from the Trinity test in 1945, and knew that ground bursts produced radioactive debris.

So you’d think that they’d have made lots of fallout studies prior to Castle. I had thought about producing some kind of map with all of the various fallout plumes through the 1950s superimposed on it, but it became harder than I thought — there are just a lot fewer fallout plumes prior to Bravo than you might expect. Why? Because prior to Bravo, they generally did not map downwind fallout plumes for shots in Marshall Islands — they only mapped upwind plumes. So you get results like this for Ivy Mike, a very “dirty” 10.4 megaton explosion that did produce copious fallout, but you’d never know it from this map:

Fallout from the 1952 "Ivy Mike" shot of the first hydrogen bomb. Note that this is actually the "back" of the fallout plume (the wind was blowing it north over open sea), and they didn't have any kind of radiological monitoring set up to see how far it went. As a result, this makes it look far more local than it was in reality. This is from a report I had originally found in the Marshall Islands database.

To make it even more clear what you’re looking at here: the wind in this shot was blowing north — so most of the fallout went north. But they only mapped the fallout that went south, a tiny amount of the total fallout. So it looks much, much more contained than it was in reality. You want to shake these guys, retrospectively.

It’s not that they didn’t know that fallout went further downwind. They had mapped the Trinity test’s long-range fallout in some detail, and starting with Operation Buster (1951) they had started mapping downwind plumes for lots of tests that took place at the Nevada Test Site. But for ocean shots, they didn’t their logistics together, because, you know, the ocean is big. Such is one of the terrible ironies of Bravo: we know its downwind fallout plume well because it went over (inhabited) land, and otherwise they probably wouldn’t have bothered measuring it.

The publicity given to Bravo meant that its fallout plume got wide, wide dissemination — unlike the Trinity test’s plume, unlike the other ones they were creating. In fact, as I mentioned before, there were a few “competing” drawings of the fallout cloud circulating internally, because fallout extrapolation is non-trivially difficult:

BRAVO fallout contours produced by the AFSWP, NRDL, and RAND Corp. Source.

But once these sorts of things were part of the public discourse, it was easy to start imposing them onto other contexts beyond islands in the Pacific Ocean. They were superimposed on the Eastern Seaboard, of course. They became a stock trope for talking about what nuclear war was going to do to the country if it happened. The term “fallout,” which was not used even by the government scientists as a noun until around 1948,1 suddenly took off in popular usage:

Google Ngram chart of the usage of the word "fallout" in English language books and periodicals. Source.

Google Ngram chart of the usage of the word “fallout” in English language books and periodicals. Source.

The significance of fallout is that it threatens and contaminates vast areas — far more vast than the areas immediately affected by the bombs themselves. It means that even a large-scale nuclear attack that tries to only threaten military sites is also going to do both short-term and long-term damage to civilian populations. (As if anyone really considered just attacking military sites, though; everything I have read suggests that this kind of counter-force strategy was never implemented by the US government even if it was talked about.)

It meant that there was little escaping the consequences of a large nuclear exchange. Sure, there are a few blank areas on maps like this one, but think of all the people, all the cities, all the industries that are within the blackened areas of the map:

Oak Ridge National Laboratory estimate of "accumulated 14-day fallout dose patterns from a hypothetical attack on the United States," 1986. I would note that these are very high exposures and I'm a little skeptical of them, but in any case, it represents the kind of messages that were being given on this issue. Source.

Oak Ridge National Laboratory estimate of “accumulated 14-day fallout dose patterns from a hypothetical attack on the United States,” 1986. I would note that these are very high exposures and I’m a little skeptical of them, but in any case, it represents the kind of messages that were being given on this issue. Source.

Bravo inaugurated a new awareness of nuclear danger, and arguably, a new era of actual danger itself, when the weapons got big, radiologically “dirty,” and contaminating. Today they are much smaller, though still dirty and contaminating.

I can’t help but feel, though, that while transporting the Bravo-like fallout patterns to other countries is a good way to get a sense of their size and importance, that it still misses something. I recently saw this video that Scott Carson posted to his Twitter account of a young Marshallese woman eloquently expressing her rage about the contamination of her homeland, at the fact that people were more concerned about the exposure of goats and pigs to nuclear effects than they were the islanders:

I’ve spent a lot of time looking at the reports of the long-term health effects on the Marshallese people. It is always presented as a cold, hard science — sometimes even as a “benefit” to the people exposed (hey, they got free health care for life). Here’s how the accident was initially discussed in a closed session of the Congressional Joint Committee on Atomic Energy, for example:

Chairman Cole: “I understand even after they [the natives of Rongelap] are taken back you plan to have medical people in attendance.”

Dr. Bugher: “I think we will have to have a continuing study program for an indefinite time.”

Rep. James Van Zandt: “The natives ought to benefit — they got a couple of good baths.”

Which is a pretty sick way to talk about an accident like this, even if all of the facts aren’t in yet. Even for a classified hearing.

What’s the legacy of Bravo, then? For most of us, it was a portent of dangers to come, a peak into the dark dealings that the arms race was developing. But for the people on those islands, it meant that “the Marshall Islands” would always be followed by “where the United States tested 67 nuclear weapons” and a terrible story about technical hubris, radioactive contamination, and long-term health problems. I imagine that people from these islands and people who grew up near Chernobyl probably have similar, terrible conversations.

A medical inspection of a Marshallese woman by an American doctor. "Project 4," the biomedical effects program of Operation Castle was initially to be concerned with "mainly neutron dosimetry with mice" but after the accident an additional group, Project 4.1, was added to study the long-term exposure effects in human beings — the Marshallese. Image source.

A medical inspection of a Marshallese woman by an American doctor. “Project 4,” the biomedical effects program of Operation Castle was initially planned to be concerned with “mainly neutron dosimetry with mice” but after the accident an additional group, Project 4.1, was added to study the long-term exposure effects in human beings — the Marshallese. Image source.

I get why the people who made and tested the bombs did what they did, what their priorities were, what they thought hung in the balance. But I also get why people would find their actions a terrible thing. I have seen people say, in a flip way, that there were “necessary sacrifices” for the security that the bomb is supposed to have brought the world. That may be so — though I think one should consult the “sacrifices” in question before passing that judgment. But however one thinks of it, one must acknowledge that the costs were high.

Notes
  1. William R. Kennedy, Jr., “Fallout Forecasting—1945 through 1962,” LA-10605-MS (March 1986), on 5. []
Redactions

The final switch: Goldsboro, 1961

Friday, September 27th, 2013

The threat of nuclear weapons accidents isn’t a new one. Even in 1945, Los Alamos physicists sweated when contemplating all that could possibly go wrong with their bombs, if they went off at the wrong place or the wrong time. Or didn’t go off at all. That’s the bind, really: a nuclear state wants a weapon that always goes off exactly when you tell it to, and never goes off any other time. That’s a hard thing to guarantee, especially when the stakes are so high in both directions, and especially since these two requirements can be directly in tension.

Schlosser - Command and Control book

I recently heard Eric Schlosser give that elegant formulation at a talk he gave last week in support of the release of his new book, Command and Control: Nuclear Weapons, the Damascus Accident, and the Illusion of Safety. I haven’t had a chance to read the book, yet (it’s currently en route), but I’m looking forward to it. I read Schlosser’s Fast Food Nation a decade (!) ago and found it completely eye-opening. But I went to his talk last week not sure what to expect. From McDonald’s to nuclear weapons accidents? Stranger things have happened, but I worried that maybe he would take the “easy” route with regards to the accidents, not bothering to learn to nitty-gritty technical details that let one talk about such things sensibly, or, at the very least, sensationalize the findings. So I was pretty pleased to find that neither seemed to be the case. Schlosser has seriously done his homework, spending 6 years digging through records, FOIAing documents, and interviewing weapons designers. His discussion of the risks seemed right on the mark so far as I could tell — they don’t need to be exaggerated one bit to be perfectly horrifying. He answered questions expertly, even a tough, devil’s-advocate one from Hugh Gusterson. So I’ve been looking forward to reading the full book.

Last week, the Guardian released a new document, obtained by Schlosser through a FOIA request, regarding one particular accident, the 1961 crash of a B-52 near Goldsboro, North Carolina, which resulted in the jettisoning of two Mark-39 hydrogen bombs. The document in question is a government nuclear expert’s evaluation of a popular account of the Goldsboro accident, in which he finds some major errors (like overstating the yield of the bomb), but ultimately concludes that at least one of the bombs was, in fact, pretty damned close to accidental detonation: “one simple, dynamo-technology, low voltage switch stood between the United States and a major catastrophe … It would have been bad news – in spades.

The bomb in question, stuck in the mud.

The bomb in question, stuck in the mud.

I’ve been watching how the above document has been discussed by people on the web. The most interesting response has been people saying, “I thought that bomb lacked a nuclear core?” You know that there have been too many nuclear weapons accidents when people start getting them confused with one another. The missing-bomb-that-maybe-lacked-a-core is the 1958 Tybee bomb, where a Mark-15 hydrogen bomb was lost near Savannah, Georgia. Different bomb, different day.

The other response I commonly saw was one that assumed that any such fears of a bomb going off accidentally were exaggerated. Now this is kind of an interesting response. For the one thing, they’re discounting a contemporary, internal, once-classified evaluation made by a relevant expert. In exchange, they’re parroting either general skepticism at the idea that a nuclear weapon could technically be unsafe, or they are parroting a standard line about how hard it is to set off an implosion bomb accidentally, because all of the lenses need to detonate at exactly the same time. Which is sometimes the right approach (though not all American bomb designs were “one-point safe” — that is, there were designs that ran a real risk of producing a nuclear yield even if just one of the explosive lenses accidentally fired), but in this case, it’s entirely irrelevant, for reasons I’ll explain below.

I’ve been in touch with Schlosser since the talk, and he shared with me a video he had (somehow) gotten his hands on produced by Sandia National Laboratory (the weapons lab that specializes in making bombs go off at just the right moment) about the Goldsboro accident. He’s put it up on YouTube for me to share with you. It is only a few minutes long and worth the watch.

I love the CGI — “all the sudden, now that weapon system is free.” The bomb looks so… liberated. And the part at the end, where they talk about how they had plenty of opportunities for future data, because there were so many accidents, is wonderfully understated. But the stuff that really hits you in your gut is the description of exactly what happened:

“All of the sudden now that weapon system [the Mk-39] is free. As the weapon dropped, power was now coming on, and the arming rods were pulled, the baroswitches began to operate.1 The next thing on the timing sequence was for the parachute to deploy. When it hit the ground, it tried to fire.” “There was still one safety device that had not operated. And that one safety device was the pre-arming switch which is operated by a 28 volt signal.” “Some people could say, hey, the bomb worked exactly like designed. Others can say, all but one switch operated, and that one switch prevented the nuclear detonation.” “Unfortunately there had been some 30-some incidents where the ready-safe switch was operated inadvertently. We’re fortunate that the weapons involved at Goldsboro were not suffering from that same malady.”

What’s amazing about the above, in part, is that everything in quotation marks is coming from Sandia nuclear weapons safety engineers, not anti-nuclear activists on the Internet. This isn’t a movie made for public consumption (and I’ve been assured that it is not classified, in case you were wondering). It’s a film for internal consumption by a nuclear weapons laboratory. So it’s hard to not take this as authoritative, along with the other aforementioned document. Anyone who brushes aside such concerns as “hysterical” is going to have to contend with the fact that this is what the nuclear weapons designers tell themselves about this accident. Which is pretty disconcerting.

There are further details in another document sent to me by Schlosser, a previously-classified review of nuclear weapons accidents from 1987 that clarifies that one of the reasons the Goldsboro bomb in particular almost detonated was because of the way it was tossed from the aircraft, which removed a horizontally-positioned arming pin. That is, an arming pin was supposed to be in a position that it couldn’t be removed accidentally, but the particulars of how violently the aircraft broke up as it crashed were what armed the bomb in question. The other bomb, the one whose parachute didn’t fire, just had its HE detonate while it was in the mud. From the 1987 review:

Before the accident, the manual arming pin in each of the bombs was in place. Although the pins required horizontal movement for extraction, they were both on a lanyard to allow the crew to pull them from the cockpit. During the breakup, the aircraft experienced structural distortion and torsion in the weapons bay sufficient to pull the pin from one of the bombs, thus arming the Bisch generator.2 The Bisch generator then provided internal power to the bomb when the pullout cable was extracted by the bomb falling from the weapons bay. The operation of the baroswitch arming system,3 parachute deployment, timer operation,4 low and high voltage thermal batteries activation, and delivery of the fire signal at the impact by the crush switch all followed as a natural consequence of the bombing falling free with an armed Bisch generator. The nonoperation of the cockpit-controlled ready-safe switch prevented nuclear detonation of the bomb. The other bomb, which free-fell, experienced HE detonation upon impact. One of the secondary subassemblies was not recovered.5

The secondary subassembly is the fusion component of the hydrogen bomb. Normally I would not be too concerned with a lost secondary in and of itself, because bad folks can’t do a whole lot with them, except that in this particular bomb, the secondary contained a significant amount of high-enriched uranium, and lost HEU is never a good thing. The government’s approach to this loss was to get an easement on the land in question that would stop anyone from digging there. Great…

Mk-39 ready-safe switch

From the video, I was also struck by the picture of the ready-safe switch then employed. I’d never seen one of these before. Presumably “S” means “safe” and “A” means “armed.” It looks ridiculously crude by modern standards, one little twirl away from being armed. This little electronic gizmo was all that stood between us and a four megaton detonation? That’s a wonderful thing to contemplate first thing in the morning. Even the later switches which they show look more crude than I’d prefer — but then again, probably all 1950s and 1960s technology is going to look crude to a modern denizen. And again, just to reiterate, we’re not talking about “merely” accidentally igniting the explosives on the primary bomb — we’re talking about the bomb actually sending a little electrical charge through the firing circuit saying “Fire!” and starting the regular, full-yield firing sequence, stopped only by this little gizmo. A little gizmo prone to accidentally firing, in some of the bombs.

Lest you think that perhaps Sandia overstates it (which seems rather unlikely), take also the testimony of Secretary of Defense Robert McNamara into account. In January of 1963, McNamara explained at a meeting between the Defense and State Departments that he was opposed to Presidential pre-delegation of nuclear weapons in part because of the danger of accidental detonation — either ours or the Soviets’. In the meeting notes, posted some time back by the National Security Archive and forwarded to me by Schlosser, McNamara’s participation is listed as follows:

Mr. McNamara went on to describe the possibilities which existed for an accidental launch of a missile against the USSR. He pointed out that we were spending millions of dollars to reduce this problem to a minimum, but that we could not assure ourselves completely against such a contingency. Moreover he suggested that it was unlikely that the Soviets were spending as much as we were in attempting to narrow the limits of possible accidental launch. He went on to describe crashes of US aircraft[,] one in North Carolina and one in Texas, where, by the slightest margin of chance, literally the failure of two wires to cross, a nuclear explosion was averted.

This one’s interesting because it embeds these accidents in a context as well — the possibility of either us, or the Soviets, accidentally launching a nuke and wondering if a full-scale nuclear exchange has to follow. It’s not quite Strangelovian, since that would require a rogue commander, but it is very Fail-Safe.

As to what the Goldsboro blast would look like, the only time we tested this warhead at full yield was the shot “Cherokee” at Operation Redwing, in 1958. It was a pretty big boom, far more impressive than some of the Hiroshima shots that have been posted along with the Goldsboro story:

Redwing_Cherokee_005

And, of course, you can use the NUKEMAP to chart the damage. I’ve added the W-39 warhead to the list of presets in NUKEMAP2, using 4 megatons as the yield (the tested yield was 3.8 megatons, though the W-39 is often stated as an even 4. I rounded up, just because quibbling over 200 kilotons seemed pointless), and a fission fraction of 55%.6 It’s a pretty big explosion, with a fallout plume capable of covering tens of thousands of square miles with hazardous levels of contamination (and nearly a thousand square miles with fatal levels). Note that the Cherokee test was a true airburst (the fireball didn’t touch the ground), and so didn’t generate any significant fallout. The Goldsboro bomb, however, was meant to operate on impact, as a surface burst, and would have created significant fallout.

Again, one doesn’t have to exaggerate the risks to find it unsettling. The bomb didn’t go off, that final switch thankfully did work as intended. But that’s cold comfort, the more you learn about the accident. Our current nuclear weapons are much safer than the Mk-39 was, back in 1961, though Schlosser thinks (following the testimony of experts) there are still some unsettling aspects about several of our weapons systems. If we are going to have nukes, he reasons, we should be willing to spend whatever it costs to make sure that they’ll be safe. That seems to me like an argument guaranteed to appeal to nobody in today’s current political climate, with the left-sorts wanting no nukes and no modernization, and the right-sorts not really wanting to talk about safety issues. But I’ll get to that more another day, once I’ve read the book.

If that bomb had gone off, we’d speak of “Goldsboro” as a grim mnemonic, in the same way that we do “Chernobyl” today. One wonders how that would have changed our approach to nuclear weapons, had the final switch not held strong.

Notes
  1. The “arming rods” were pull-out switches that would activate when the weapon left the bomb bay. The baro(meter) switches were pressure sensitive switches that would make sure the bomb was nearing the appropriate height before starting the next sequence of arming. In the World War II bombs, the next stage in the sequence would be to consult radar altimeters to check the precise distance from the ground. The Goldsboro bombs were set to go off on ground impact. []
  2. A Bisch generator, as the context implies, is an electrical pulse generator. []
  3. Again, a pressure-sensitive switch that tried to guarantee that the bomb was roughly where it was supposed to be. []
  4. Timer switches were often used to make sure that the bomb cleared the aircraft before seriously starting to arm. []
  5. R.N. Brodie, “A Review of the US Nuclear Weapon Safety Program – 1945 to 1986,” SAND86-2955 [Extract] (February 1987). []
  6. Chuck Hansen, in his Swords of Armageddon, estimates that shots Cherokee and Apache of Operation Redwing had an average fission fraction of 55%, but isn’t able to get it any more precise than that. Given what I’ve read about the bomb — that it used an HEU secondary, for example — I would expect it to be at least 55%, if not more. It seems like a pretty “dirty” weapon, emphasizing a big yield in a relatively small package over any other features. See Chuck Hansen, Swords of Armageddon, V-224 (footnote 325). []
Visions

Enough Fallout for Everyone

Friday, August 3rd, 2012

Nuclear fallout is an incredible thing. As if the initial, prompt effects of a nuclear bomb weren’t bad enough — take that and then spread out a plume of radioactive contamination. The Castle BRAVO accident was the event that really brought this to the public forefront. I mean, the initial effects of 15 megaton explosion are pretty stunning in and of themselves:

But the fallout plume extended for hundreds of miles:

Why yes, you can get this on a coffee mug!

Superimposed on an unfamiliar atoll, it’s hard to get a sense of how long that plume is. Put it on the American Northeast, though, and it’s pretty, well, awesome, in the original sense of the word:

Of course, it’s all about which direction the wind blows, in the end.

And remember… that’s just a single bomb!

Of course, if you’re interested in the more diffuse amounts of radioactivity — more than just the stuff that you know is probably bad for you — the fallout maps get even more interesting. Here’s what the BRAVO fallout did over the next month or so after the detonation:1

Now, you can’t see the numbers there, but they aren’t high — it’s not the same as being immediately downwind of these things. They’re low numbers… but they’re non-zero. But one of the “special” things about nuclear contaminants is that you can track them for a very long time, and see exactly how one test — or accident — in a remote area is intimately connected to the entire rest of the planet. 

And, in fact, nearly everyone born during the era of atmospheric nuclear testing had some tiny bits of fallout in their bones — you can even use it to determine how old a set of teeth are, to a very high degree of accuracy, by measuring their fallout content. (And before you think atmospheric testing is a matter of ancient history, remember that France and China both tested atmospheric nuclear weapons long after the Limited Test Ban Treaty! The last atmospheric test, by China, was in 1980!)

The same sorts of maps are used to show the dispersion of radioactive byproducts of nuclear reactors when accidents occur. I find these things sort of hypnotizing. Here are four “frames” from a simulation run by Lawrence Livermore National Laboratory on their ARAC computer showing the dispersion of radioactivity after the Chernobyl accident in 1986:2

Chernobyl ARAC simulation, day 2

Chernobyl ARAC simulation, day 4

Chernobyl ARAC simulation, day 6

Chernobyl ARAC simulation, day 10

Pretty incredible, no? Now, the odds are that there are lots of other contaminants that, could we track them, would show similar world-wide effects. Nuclear may not be unique in the fact that it has global reach — though the concentrations of radioactivity are far higher than you’d find anywhere else — but it may be unique that you can always measure it. 

Yesterday I saw a new set of plots predicting the dispersion of Caesium-137 after the Fukushima accident from 2011. These are just models, not based on measurements; and all models have their issues, as the modelers at the Centre d’Enseignement et de Recherche en Environnement Atmosphérique (CEREA) who produced these plots acknowledge.

Here is their map for Cs-137 deposition after Fukushima. I’m not sure what the numbers really mean, health-wise, but the long reach of the accident is dramatic:

Map of ground deposition of caesium-137 for the Fukushima-Daichii accident

Map of ground deposition of caesium-137 for the Fukushima-Daichii accident by Victor Winiarek, Marc Bocquet, Yelva Roustan, Camille Birman, and Pierre Tran at CEREA. (Source)

Compare with Chernobyl. (Warning: the scales of these two images are different, so the colors don’t map onto the same values. This is kind of annoying and makes it hard to compare them, though it illustrates well the local effects of Chernobyl as compared to Fukushima.)

Map of ground deposition of caesium-137 for the Chernobyl accident

Map of ground deposition of caesium-137 for the Chernobyl accident, by Victor Winiarek, Marc Bocquet, Yelva Roustan, Camille Birman, and Pierre Tran at CEREA. (Source)

Lastly, they have an amazing animated map showing the plume as it expands across the Pacific. It’s about 5MB in size, and a Flash SWF, so I’m just going to link to it here. But you must check it out — it’s hypnotic, strangely beautiful, and disturbing. Here is a very stop-motion GIF version derived from their map, just to give you an incentive to see the real thing, which is much more impressive:

Fukushima-Daichii activity in the air (caesium-137, ground level) (animated)

There’s plenty of fallout for everyone — well enough to go around. No need to be stingy. And nearly seven decades into the nuclear age, there’s a little bit of fallout in everyone, too.

Update: The CEREA site seems to be struggling a bit. Here’s a locally-hosted version of the full animation. I’ll remove this when CEREA gets up and running again…

Notes
  1. Image from “Nature of Radioactive Fall-Out and Its Effects on Man, Part 1,” Hearings of the Joint Committee on Atomic Energy, Special Joint Subcommittee on Radiation (May 27-29 and June 3, 1957), on 169. []
  2. These images are courtesy of the DOE Digital Archive. []
Meditations

Fukushima: Is it “Nuclear Secrecy” or Just Capture?

Monday, March 12th, 2012

Two very different stories have been setting off my “nuclear secrecy” Google Alert switchboard for the past two weeks.

The first is Iran and their alleged secretiveness as an indicator of their alleged bad intentions. I’m still wrapping my head around that one.1

The second is the Fukushima accident, which has hit its one-year anniversary. It’s not something I’ve talked about on here before, and this post is something of an explanation of why.

Fukushima first-year dose estimate by the NNSA, via the US Department of Energy

There is little doubt that the Japanese government failed to disclose the severity of the accident as it was happening, or the potential outcomes that were within a realistic possibility. Tepco, the power utility that runs Fukushima, similarly has developed a strong reputation for non-disclosure or selective-disclosure.

All of which brings back some grim memories of the Soviet Union’s lack of disclosure surrounding the early days of Chernobyl. By comparison with these two nuclear accidents, Three Mile Island, even with the cacophony of contradictory information that was released, seems like a comparatively open event in retrospect.

I don’t lump any of these incidents, though, under the heading of “nuclear secrecy.” Why not?

For me, what makes nuclear secrecy an entity worth discussing is not that it happens to be secrecy that applies to nuclear technology. Rather, it’s the secrecy that surrounds the specific security implications associated with military and dual-use nuclear technologies: in the end, it’s about the bomb, not just nuclear qua nuclear. The ability to concentrate “absolute” military power into a small package has changed the international order — and various national orders — since 1945. The locating of the source of that newfound political power in knowledge – instead of, say, materials or industrial know-how, for example — was the first step towards settling on information control (secrecy) as the form of its control. Why this was so, and whether it was a good idea, or even worked, is the subject of my overall research and the (someday) forthcoming book. But it’s this Hobbesian use of the bomb as the ultimate argument for secrecy that makes nuclear secrecy an interesting thing, above and beyond the bureaucratic secrecy that clusters around all complicated organizations, or the somewhat more banal forms of generic military secrecy or diplomatic secrecy.

Nowhere is this “special” nature of the bomb more explicit than in the United States, where the restricted data legal concept (after which this blog is named) actually carves out a completely parallel classification system for information related to nuclear weapons, above and beyond “normal” defense secrets.

The bomb might seem like an overly specific case, focusing primarily on weapons production methods, designs, and stockpiles. But a tremendous amount of other information “devolves” into these three categories. Example: Nuclear reactors originally fell into all three categories, because they were used to produce plutonium, they gave you information about nuclear properties that were for awhile considered classified, and because knowledge of American reactor operations could help you estimate the size of the US plutonium inventory, and thus the stockpile. There are far more amusing examples, of course: the amount of toilet paper used by a secret site, for example, can help you get estimates as to the personnel levels there, which can then be traced back to the amount of material or work being produced, and so on.

Read the full post »

Notes
  1. How secret is “secretive”? Does the Qom facility count as secretive because it wasn’t immediately disclosed? What’s the IAEA requirement for when you disclose a facility — at what point in its construction/planning? Are the Iranians any more secretive about these things than anyone else? Does having another state assassinating your scientists justify additional security/secrecy? I’m still mulling. []