Posts Tagged ‘Bad ideas’


Sakharov’s turning point: The first Soviet H-bomb test

Friday, January 31st, 2014

The Soviets set off their first megaton-range hydrogen bomb in November 1955. It was the culmination of many years of effort, in trying to figure out how to use the power of nuclear fission to release the power of nuclear fusion in ways that could be scaled up arbitrarily.1 The Soviet bomb was designed to be a 3-megaton warhead, but they set it off at half strength to avoid too much difficulty and fallout contamination. Unlike the US, the Soviets tested their version version by dropping it out of a bomber — it was not a big, bulky, prototype like the Ivy Mike device. But it was not an uneventful test. The details are little talked about, but it serves as an impressive parable about what can go wrong when you are dealing with science on a big scale.

Andrei Sakharov, from nuclear weapons designer to aged dissident.

Andrei Sakharov, from young nuclear weapons designer to aged dissident. Source.

Andrei Sakharov has a stunning chapter on it in his memoirs. It makes for an impressive story in its own right, but Sakharov also identifies the experience as a transformative one in his own thinking about the responsibility of the scientist, as he made his way from nuclear weapons designer to political dissident.2

Sakaharov starts out by talking about going to Kazakhstan to see the test. He had by this time been assigned two armed KGB officers, known euphemistically as “secretaries,” whose jobs were to act as bodyguards and “to prevent undesirable contacts.” Sakharov claims not to be have been too bothered by them. They lived next door.

The test of the device, code-named RDS-37, was to be the 24th Soviet nuclear test, and was the largest ever tested at the Semipalatinsk test site. This created several logistical difficulties. In order to avoid local nuclear fallout, it was going to be an airburst. The size of the bomb, however, brought up the possibility that it might accidentally blow the bomber that delivered it out of the sky. To avoid this, the bomber was painted white (to reflect the thermal radiation), and a big parachute was applied to the bomb so that the bomber could get away fast enough. Sakharov was satisfied enough with the math on this that he asked if he could ride along on the bomber, but the request was denied.

Sakharov’s account lingers on the incongruity between testing nuclear weapons in beautiful, wild places. Siberia was “a new and spellbinding experience for me, a majestic, amazingly beautiful sight.” He continued: “The dark, turbulent waters of the Irtysh, dotted with a thousand whirlpools, bore the milky-blue ice floes northward, twisting them around and crashing them together. I could have watched for hours on end until my eyes ached and my head spun. Nature was displaying its might: compared to it, all man’s handiwork seems paltry imitation.

The RDS-37 test device. Source.

The RDS-37 test device. Source.

A test trial-run on November 18th went smoothly, but the first test attempt, on November 20th, did not. As David Holloway recounts in Stalin and the Bomb, that same Siberian wintery majesty that dazzled Sakharov made for difficult testing conditions.3 The fully-loaded Tu-16 bomber had to abort when the test site was unexpectedly covered by clouds, making them unable to see the target aiming point and rendering the optical diagnostic systems inoperable. The plane was ordered to land, only now it had a fully-armed experiment H-bomb on board. There was concern that if it crashed, it could result in a nuclear yield… destroying the airfield and a nearby town. The airfield had meanwhile iced over. Igor Kurchatov, the lead Soviet nuclear weapons scientist, drove out to the airfield himself personally to see the airfield. Sakharov assured him that even if it crashed, the odds of a nuclear yield were low. An army unit at the airfield quickly worked to clear the runway, and so Kurchatov ordered the plane to land. It did so successfully. Kurchatov met the crew on the field, no doubt relieved. Sakharov recalls him saying, “One more test like [this one] and I’m retiring.” As for Sakharov, he called it “a very long day.”

Two days later, they gave it another go. This time the weather cooperated, as much as Siberian weather cooperates. The only strange thing was a temperature inversion, which is to say, at higher altitudes it was warmer than at lower altitudes, the opposite of the usual. The meteorologists gave the go-ahead for the testing.

Sakharov stayed at a laboratory building on the outskirts of a small town near the test site. An hour before the test, Sakharov saw the bomber rising above the town. It was “dazzling white,” and “with its sweptback wings and slender fuselage extending far forward, it looked like a sinister predator poised to strike.” He recalled that “for many peoples, the color white symbolizes death.” An hour later, a loud-speaker began the countdown.

The white bomber. Source.

The white bomber. Source.

Sakharov described the test in vivid detail:

This time, having studied the Americans’ Black Book4, I did not put on dark goggles: if you remove them after the explosion, your eyes take time to adjust to the glare; if you keep them on, you can’t see much through the dark lenses. Instead, I stood with my back to ground zero and turned around quickly when the building and horizon were illuminated by the flash. I saw a blinding, yellow-white sphere swiftly expand, turn orange in a fraction of a second, then turn bright red and touch the horizon, flattening out at its base. Soon everything was obscured by rising dust which formed an enormous, swirling grey-blue cloud, its surface streaked with fiery crimson flashes. Between the cloud and the swirling durst grew a mushroom stem, even thicker than the one that had formed during the first [1953] thermonuclear test. Shock waves crisscrossed the sky, emitting sporadic milky-white cones and adding to the mushroom image. I felt heat like that from an open furnace on my face — and this was in freezing weather, tens of miles from ground zero. The whole magical spectacle unfolded in complete silence. Several minutes passed, and then all of the sudden the shock wave was coming at us, approaching swiftly, flattening the feather-grass.

“Jump!” I shouted as I leaped from the platform. Everyone followed my example except for my bodyguard (the younger one was on duty that day); he evidently felt he would be abandoning his post if he jumped. The shock wave blasted our ears and battered our bodies, but all of us remained on our feet except for the bodyguard on the platform, who fell and suffered minor bruises. The wave continued on its way, and we heard the crash of broken glass. Zeldovich raced over to me, shouting: “It worked! It worked! Everything worked!” Then he threw his arms around me. […]

The test crowned years of effort. It opened the way for a whole range of devices with remarkable capabilities, although we still sometimes encountered unexpected difficulties in producing them.

But they soon learned that a bruised bodyguard was the least of the injuries sustained in the test. Scientists and soldiers had been stationed far closer to the blast than Sakharov was. The scientists were fine — they were lying flat on the ground and the blast wave caused them no injury. One of them lost his cool and ran away from the blast, but he was only knocked down by it. But a nearby trench held a platoon of soldiers, and the trench collapsed. One young soldier, in his first year of service, was killed.

RDS-37 detonation

RDS-37, detonating. This is considerably sped up; it shows about 50 seconds of footage compressed into only a few seconds. Video source here.

There was also a nearby settlement of civilians affected by the blast wave. In theory it was at a distance remote enough to avoid anything serious; this had been calculated. But the aforementioned inversion layer reflected the shock wave back down to Earth with unusual vehemence — underscoring how even a little misunderstanding of the physics can translate into real problems when you are talking about millions of tons of TNT (something learned by the US a year earlier, at the Castle Bravo test). The inhabitants of the town were in a primitive bomb shelter. After the flash, they exited to see the cloud. Inside the shelter, however, was left a two-year-old girl, playing with blocks. The shock wave, arriving well after the flash, collapsed the shelter, killing the child. 

The ceiling of a woman’s ward of a hospital in another nearby village collapsed, seriously injuring many people. Glass windows broke at a meat-packing plant a hundred miles from the test site, sprinkling ground beef with splinters. Windows broke throughout the town where Sakharov was stationed.

RDS-37, seen from a local town. Also sped up. Same source as the previous.

The consequences of an explosion are hard to predict,” Sakharov concluded.

Had we been more experienced, the temperature inversion would have caused us to delay the test. The velocity of the shock wave increases as the temperature does: if the air temperature rises with altitude, the shock wave bends back towards the ground and does not dissipate as fast under normal conditions. This was the reason the shock wave’s force exceeded our predictions. Casualties might have been avoided if the test had been conducted as scheduled on November 20, when there was no temperature inversion.

As with Castle Bravo, there was a grim, almost literary connection between technical success and human disaster. They had shown the way forward for deployable, multi-megaton hydrogen bombs, but with a real cost — and that cost only an insignificant hint of what would happen if the weapons were used in war. Sakharov concluded:

We were stirred up, but not just with the exhilaration that comes with a job well done. For my part, I experienced a range of contradictory sentiments, perhaps chief among them a fear that this newly released force could slip out of control and lead to unimaginable disasters. The accident reports, and especially the deaths of the little girl and the soldier, heightened my sense of foreboding. I did not hold myself personally responsible for their deaths, but I could not escape a feeling of complicity.

That night, the scientists, the politicians, and the military men dined well. Brandy was poured. Sakharov was asked to give the first toast. “May all of our devices explode as successfully as today’s, but always over test sites and never over cities.”

Sculpture of Andrei Sakharov by Peter Shapiro, outside the Russia House Club & Restaurant on Connecticut Ave in Washington, DC. Image source.

Sculpture of Andrei Sakharov by Peter Shapiro, outside the Russia House Club & Restaurant on Connecticut Ave in Washington, DC. Image source.

The immediate response was silence. Such things were not to be said. One of the military higher-ups flashed a crooked grin, and stood to give his own toast. “Let me tell a parable. An old man wearing only a shirt was praying before an icon. ‘Guide me, harden me. Guide me, harden me.’ His wife, who was lying on the stove, said: ‘Just pray to be hard, old man, I can guide it myself.’ Let’s drink to getting hard.

Sakharov blanched at the crudity (“half lewd, half blasphemous”), and its serious implications. “The point of his story,” he later wrote, “was clear enough. We, the inventors, scientists, engineers, and craftsmen, had created a terrible weapon, the most terrible weapon in human history; but its use would lie entirely outside our control. The people at the top of the Party and military hierarchy would make the decisions. Of course, I knew this already — I wasn’t that naive. But understanding something in an abstract way is different from feeling it with your whole being, like the reality of life and death. The ideas and emotions kindled at that moment have not diminished to this day, and they completely altered my thinking.

  1. The Soviets tested their first thermonuclear bomb in 1953, the RDS-6s, which used fusion reactions. But it was not a true, multi-megaton capable hydrogen bomb. The 1953 device was “just” a very, very big boosted bomb, where 40 kilotons of fissioning produced 80 kilotons of fusioning which in turn produced another 280 kilotons of fissioning, for 400 kilotons total. The design could not be scaled up arbitrarily, though, and it did not use radiation implosion (like the Teller-Ulam design, known in the USSR as the “Third Idea.” It was a big bomb, but the 1955 test was the design that became the basis for their future nuclear warheads. []
  2. Andrei Sakharov, Memoirs, trans. Richard Lourie (New York: Knopf, 1990), 188-196. []
  3. David Holloway, Stalin and the bomb: The Soviet Union and atomic energy, 1939- 1956 (New Haven: Yale University Press, 1994), 314-316. []
  4. From elsewhere in the Memoirs, it seems that Sakharov may be referring here to the 1950 edition of Samuel Glasstone’s The Effects of Atomic Weapons. There was a hardcover edition that apparently had a black cover. Sakharov notes that the nick-name only “partly” came from the cover; he implies that the contents are “black” as well. However there is nothing about goggles or glare in the version of the text I have, so maybe it is something different. []

Nixon and the bomb: “I just want you to think big, Henry!”

Friday, October 25th, 2013

Richard Nixon was a President so utterly fascinating that if he didn’t exist, historians would have had to invent him. He was both clever and odious, politically appealing but personally unpleasant. Flawed enough that he managed to pointlessly lose the Presidency because of his insecurities, his desire for even more of a landslide than he already had. Anti-semitic, homophobic, racist — but also canny, both with regards to foreign policy and American domestic politics. And what a gift for historians of the future, that he compulsively recorded himself saying awful things? It’s almost too much to be believed, the truth being much more stranger than any fictionalized President could be.

Nixon portrait cropped

We don’t talk much about Nixon and the bomb, which is perhaps a little odd. The Nixon years were those of détente, which has something to do with it, and there were no “close calls” or fiery public rhetoric about the bomb. Nixon only rarely shows up personally in my work; he didn’t appear to get involved with nuclear matters to the degree that Kennedy or Eisenhower did, for example, much less those like Reagan or Truman.

But this is an oversight. Nixon and the bomb is an immensely interesting subject, as I recently learned. Last week I was at a nuclear history/policy conference hosted by Francis Gavin, among a few others, that was itself immensely interesting and fruitful. Before going, I thought I should get around to reading Gavin’s latest book, Nuclear Statecraft: History and Strategy in America’s Atomic Age, since he had bothered to invite me and all.1

Gavin - Nuclear Statecraft - cover

It’s incredibly interesting as a book of history written with a mind towards those who care about policy. Each chapter tackles a major issue in nuclear history and gives a unique perspective or new findings on it. For example, the Kennedy and Johnston administrations get lots of credit for adopting a “flexible response” approach to nuclear targeting, but Gavin reports that while they gave speeches on this, in practice their war plans were little more flexible than Eisenhower’s, because privately they judged flexibility to be difficult and dangerous. That was new to me, and a nice point about the difference between public statements and official policy, and the trickiness of divining information about secret programs from the party line.

The chapter that really wowed me was on Nixon. Again, I hadn’t given Nixon and the bomb all that much thought. But Gavin points out that it deserves much more attention, because while on paper Nixon looked like an exemplary arms controller, but in private, he is revealed as a total maniac something much more complicated.

For his arms control cred, just consider that Nixon was the one who signed the SALT treaty, the ABM treaty, and the Biological Weapons Convention. He was also President when the Nuclear Non-Proliferation Treaty was ratified, and when the SALT II talks began. Kind of a non-trivial list of treaties and agreements — an impressive record for any US President. But as Gavin puts it:

The documents, however, reveal that Kissinger and, especially, Nixon had a different notion of how nuclear weapons affected international relations. … Theirs was a realist view—they believed that world politics was driven, as it had been for centuries, by geopolitical competition between great powers. The “nuclear revolution” had not changed this core feature of the international system. In relations with the Soviets, the message to their opponents was clear: “Look, we’ll divide up the world, but by God you’re going to respect our side or we won’t respect your side.”2

As evidence of this, Gavin has lots of excerpts from conversations between Nixon and Kissinger about nukes and treaties. They are universally disdainful of arms control. While Nixon was beginning the bomb the hell out of Cambodia (one of his least popular policies), he remarked to Kissinger: “Looking back over the past year we have been praised for all the wrong things: Okinawa, SALT, germs, Nixon Doctrine. Now [we are] finally doing the right thing.” Which tells you a lot about Nixon’s worldview: what mattered to him, in the end, was winning in Vietnam. Full stop. Everything else was just a distraction.

Nixon contemplative

As for arms control, Nixon told Kissinger that “I don’t give a damn about SALT; I just couldn’t care less about it.” On the kinds of technical matters that concerned security wonks, like the number of radars or missile interceptors, Nixon privately explained that “I don’t think it makes a hell of a lot of difference,” and that he thought the arms controllers were real chumps about this kind of thing. He opposed an anti-ballistic missile site in the nation’s capital because:

I don’t want Washington. I don’t like the feel of Washington. I don’t like that goddamn command airplane or any of this. I don’t believe in all that crap. I think the idea of building a new system around Washington is stupid.

Which you have to admit is sort of a novel argument against anti-ballistic missiles, right? Because you don’t actually like the nation’s capital that you’re President of. He dismissed the Biological Weapons Convention as “the silly biological warfare thing, which doesn’t mean anything,” as opposed to what he considered the really important stuff — again, the war in Vietnam.3

For Dick and Henry, treaties were just pieces of paper that would probably be violated the moment they proved less than useful for a state. Realpolitik, plain and simple. But they were not just flying by the seat of their pants. Their approach to international politics was, Gavin argues, coherent. It just didn’t give a lot of credence to the idea that nuclear weapons had any special importance with regards to international order, since they really didn’t think that they were going to get into a genuine shooting war with the USSR anytime soon. Worse, they thought that arms control successes could lead towards the Soviets attempting to take concessions elsewhere — that if they were “good” in one arena they could then get away with being “bad” in another.

Dick and Henry

But my favorite quotes are from Nixon about Vietnam. During a spring offensive by the North Vietnamese in 1972, Nixon told Kissinger:

We’re going to do it. I’m going to destroy the goddamn country, believe me, I mean destroy it if necessary. And let me say, even the nuclear weapons if necessary. It isn’t necessary. But, you know, what I mean is, what shows you the extent to which I’m willing to go. By a nuclear weapon, I mean that we will bomb the living bejeezus out of North Vietnam and then if anybody interferes we will threaten the nuclear weapons.

A week later, he continued to a somewhat horrified Kissinger:

Nixon: I’d rather use the nuclear bomb. Have you got that ready?
Kissinger: That, I think, would just be too much.
Nixon: A nuclear bomb, does that bother you?… I just want you to think big, Henry, for Christ’s sake! The only place where you and I disagree is with regard to the bombing. You’re so goddamned concerned about civilians, and I don’t give a damn. I don’t care.
Kissinger: I’m concerned about the civilians because I don’t want the world to be mobilized against you as a butcher.4

Yeesh. Which just goes to show, that Nixon’s realpolitik approach to nuclear weapons does seem to be slightly unhinged at times — that nukes were not necessarily off the table when he thought about the things he really cared about, at least when he was trying to get a rise out of Kissinger.

As for the NPT, Nixon opposed it during his election campaign, both because he felt treaties were by themselves unenforcible and because he thought there might be some American allies who could use their own nukes. (As a possible example of the kind of difficulty the NPT created, consider that Nixon was the one who helped formulate the pact with Golda Meir that involved Israel never admitting it possessed nuclear weapons so as to maintain good relations with the USA. The NPT put limitations on the US with regards to its Middle Eastern ally, which is not something Nixon would have been happy about.)

Nixon madman

Lastly, there is the “madman” approach that Nixon and Kissinger cooked up — that Kissinger should convince the Soviets that Nixon was unhinged enough to start nuking if things went too sour in Vietnam or elsewhere. This is perhaps Nixon’s most significant engagement with the nuclear question, and it was all psychological, all ploy. And, as Gavin points out, of questionable effectiveness.

Gavin doesn’t defend Nixon’s position on nukes and treaties; he just points out that Nixon actually had a position, and that it was actually deeply at odds with his (mostly positive) public record. The reason Nixon felt free to sign so many agreements is in part because he didn’t take them very seriously. How’s that for an ironic twist? If you don’t think arms control treaties actually matter, then what’s the harm in signing a few more of them?

  1. Francis Gavin, Nuclear Statecraft: History and Strategy in America’s Atomic Age (Cornell University Press, 2012). []
  2. Gavin, 108. []
  3. Gavin, 109-110. []
  4. Gavin, 116, with some of the rest of the quote filled out from elsewhere. []

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:


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.

  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). []

Fears of a German dirty bomb

Friday, September 6th, 2013

For good reason, much has been made of the initial fear of a German atomic bomb. But there was another, lesser-known atomic fear as well. If the Germans could make nuclear reactors — which the Americans thought they were probably doing — could they not take the dangerously-radioactive spent-fuel out of them and use them to make dirty bombs? 

Hanford spent fuel rods — the sort of thing that could have been weaponized during World War II as a radiological weapon.

Hanford spent fuel rods — the sort of thing that could have been weaponized during World War II as a radiological weapon.

In the summer of 1942, Arthur Compton, head of the University of Chicago’s Metallurgical Laboratory, wrote a memo to Harvard President and atomic-bomb big-wig James B. Conant expressing the need for “protection against ionizing bombs”:

We have become convinced there is real danger of bombardment by the Germans within the next few months using bombs designed to spread radio-active materials in lethal quantities. … Since protection against the danger from such bombs will be primarily a matter of detection of radiation and instruction with regards to the dangers, it is essential that the matter be brought at once to the attention of the appropriate military officers.1

Compton and his scientists were, at the time, working under the assumption that the Germans were ahead of the Americans, and had already gotten a nuclear reactor running. They estimated that with a 100 kilowatt reactor, 100,000 Curies of radioactivity could be produced daily for bomb usage.

A radiation survey device of the sort produced during World War II by the Victoreen Instrument Company in Cleveland, in collaboration with the University of Chicago scientists.

A radiation survey device of the sort produced during World War II by the Victoreen Instrument Company in Cleveland, in collaboration with the University of Chicago scientists.

A result of this was that in the fall of 1942, the first steps were taken to, at a minimum, detect whether the Germans used any kind of radiological attack against the Allies. Survey meters were developed that would trigger alarms if they detected high levels of radioactivity. These were secretly dispersed to Manhattan District offices in Boston, Chicago, New York, San Francisco, and Washington, DC. At each location, a small number of officers were trained in their use. Further instruments were held in reserve in case they needed to be deployed further. If the alarms went off,  or if there were other suspicious signs (like reports of a large-scale blackening of photographic film), scientists at the University of Chicago were kept on the ready to be brought in to assess the situation.2

This was a fairly small program, as far as they go. Those involved were acutely aware that the secrecy of the atomic bomb made it impossible to adequately prepare for this possibility. They were stuck in a bind that was very common during the wartime period. The atomic bomb was, at that time, what I like to call an “absolute secret”: the fact that there was a “secret” at all was itself a secret. They could not draw attention to matters relating to atomic energy without drawing attention to the fact that they were engaged in a secret research program with regards to atomic energy. This is a very peculiar situation, one primarily specific to the war, when the secrecy of the project could not be acknowledged (they could not simply say, “oh, the details are secret,” as they could in the Cold War).

What did they think the Germans would do with such a radiological weapon? They considered four possibilities. First, it could be used as an “area-denial” weapon, by making areas uninhabitable. Second, it could be used to contaminate critical war infrastructure (e.g. airports). Third, it could be used as a “radioactive poison gas” to attack troops. Fourth, it could be used “against large cities, to promote panic, and create casualties among civilian populations.”3 Their assessment of the effects, by 1943, was grim:

Areas so contaminated by radioactive material would be dangerous until decay of the material took place, perhaps for weeks or months. … As a gas warfare instrument the material would be ground into particles of microscopic size to form dust and smoke and distributed by a ground-fired projectile, land vehicles, or aerial bombs.  In this form it would be inhaled by personnel.  The amount necessary to cause death to a person inhaling the material is extremely small.  It has been estimated that one millionth at a gram accumulating in a person’s body would be fatal.  There are no known methods of treatment for such a casualty.4

In the time-honored method of worrying about threats, they also then immediately realized that maybe the United States should be weaponizing fission products: “It is the recommendation of this Subcommittee that if military authorities feel that the United States should be ready to use radioactive weapons in case the enemy started it first, studies on the subject should be started immediately.” Note that this isn’t really a deterrent capability, it is a response capability. Deterrence requires your enemy knowing that you have the capability to respond, and secrecy precluded true deterrence.

1943 - Oppenheimer to Fermi

In this context, there is an interesting letter in the J. Robert Oppenheimer papers at the Library of Congress, where Oppenheimer is writing to Enrico Fermi in May 1943 on “the question of radioactively poisoned foods.” From the context, it is clear that both Edward Teller and Fermi had devoted time to this project. The full document is available here. Two parts stand out. One is that one of the acute problems in looking into the issue was, as Oppenheimer put it, difficult to study the subject “without telling anyone about it.” That is, it would be hard to investigate some of the substances in question “without letting a number of people into of the secret of why we want” the substances. The “absolute secret” bind again.

The other is Oppenheimer’s criteria for the project being worth looking into:

…I think that we should not attempt a plan unless we can poison food sufficient to kill a half a million men, since there is no doubt that the actual number affected will, because of non-uniform distribution, be much smaller than this.5

Frank Oppenheimer later called this a very “bloodthirsty” statement by his brother; the historian Barton Bernstein instead argued that this was just scientists trying to help the war effort.6 Either way, it makes Oppenheimer look like a very cold fish indeed. And not much of a “dove.” Even if one isn’t clear how much of a “non-uniform distribution” he was assuming.

1943 - Oppenheimer to Fermi - quote

The offensive angle was basically dropped — they didn’t think they’d need it, and they were focused intently on making the actual atomic bomb, a much more devastating weapon. But defensive measures did proceed. By late 1943, it was thought that the use of radioactive poisons against the UK by the Germans was of low probability, but an unpleasant possibility.7 To avoid being completely taken by surprise in such an event, General Groves (with the concurrence of General Marshall) had four officers from the European Theater of Operations staff briefed on the subject “under most complete secrecy,” and a Manual on Use of Radioactive Materials in Warfare was drawn up for these four officers. Signals officers were instructed to report any “peculiar or unexplained effects” on photographic films or personnel, and the officers in question were given radiation detection instruments to use in the case of suspected cases.

In March 1944, General Groves had the matter brought to the attention of General Dwight D. Eisenhower, commanding general of the Supreme Headquarters Allied Expeditionary Force, fearing that the Nazis might use such weapons to prevent an Allied invasion of Europe. Eisenhower concluded that since the Combined Chiefs of Staff had not brought up the issue, that they must consider that “the enemy will not implement this project.” To keep secrecy, in order to “to avoid a possible scare,” Eisenhower informed only a handful of people, which he acknowledged was not really enough to counter “enemy action of this nature”: “No US or British Commander participating in OVERLORD [the landing at Normandy] has been briefed.” However, radiation detectors were being kept in the UK for deployment on short notice, and a “cover” letter was sent out with symptoms of radiation poisoning listed as a “mild disease of unknown etiology” that was going around, requesting any medical officers to report further cases.8

Dry-run of using radiation detection equipment during a beach landing, as part of "Operation Peppermint." Source.

Team performing a dry-run of a beach landing with radiation detection equipment, as part of “Operation Peppermint.” Source.

The plan to deploy radiation monitoring during the D-Day invasions was dubbed “Operation Peppermint,” one of the more amusing code-names of the war. Dry runs of the detection apparatus were taken before D-Day, and German bomb craters were surveyed for radioactive residues, but since no evidence of German radiological weapons preparations or use were uncovered, the “Peppermint” preparations were never put into effect. 

We now know that the Germans never got anywhere near this kind of plan. They didn’t even get a reactor running by the end of the war, the necessary prerequisite for this kind of operation. It wasn’t a totally crazy fear, though. There are aspects of radiological warfare which would make it preferable to, say, chemical warfare from the German point of view. Still, there’s an aspect to this of the old saying, “when the only tool you have is a hammer, every problem looks like a nail.” When you’re studying radioactive hazards intently, every threat looks like a radioactive hazard.

The secrecy angle is what intrigues me the most about this story: the secrecy of the bomb made it difficult to enact serious preparation from this related, but separate threat. The secrecy of one fear made addressing another fear difficult, because the relevant information of both fears were too deeply entangled. 

  1. Arthur H. Compton to James B. Conant (15 July 1942), Bush-Conant file, Roll 7, Target 10, Folder 75, “Espionage.” []
  2. Manhattan District History, Book 1, Volume 14, Foreign Intelligence Supplement No. 2 (Peppermint), 31 July 1952. []
  3. Use of Radioactive Material as a Military Weapon” (n.d., c.a. early 1943). []
  4. Ibid. []
  5. J. Robert Oppenheimer to Enrico Fermi (25 May 1943), J. Robert Oppenheimer Papers, Library of Congress. []
  6. Barton J. Bernstein, “Oppenheimer and the Radioactive Poison Plan,” Technology Review, 88 (May-June 1985), 14-17. There is also some follow-up in Barton J. Bernstein, “Four physicists and the bomb: The early years, 1945-1950,” Historical Studies in the Physical and Biological Sciences, 18, No. 2 (1988), pp. 231-263, on 252-253. []
  7. Leslie Groves to George C. Marshall (30 November 1944), Manhattan Engineer District (MED) records, Records of the Army Corps of Engineers, RG 77, National Archives and Records Administration, Box 64, “Security.” []
  8. Dwight D. Eisenhower to George Marshall (11 May 1944), Correspondence (“Top Secret”) of the Manhattan Engineer District, 1942-1946, microfilm publication M1109 (Washington, D.C.: National Archives and Records Administration, 1980), Roll 5, Target 8, Folder 18, “Radiological Defense.” []
Redactions | Visions

Castle Bravo revisited

Friday, June 21st, 2013

No single nuclear weapons test did more to establish the grim realities of the thermonuclear age than Castle BRAVO. On March 1, 1954, it was the highest yield test in the United States’ highest-yield nuclear test series, exploding with a force of 15 million tons of TNT. It was also the greatest single radiological disaster in American history. 

Castle BRAVO, 3.5 seconds after detonation, photo taken from a distance of 75 nautical miles from ground zero, from an altitude of 12,500 feet. From DTRIAC SR-12-001.

Castle BRAVO, 3.5 seconds after detonation, photo taken from a distance of 75 nautical miles from ground zero, from an altitude of 12,500 feet. From DTRIAC SR-12-001.

Among BRAVO’s salient points:

  • It was the first “dry fuel” hydrogen bomb test by the United States, validating that lithium-deuteride would work fine as a fusion fuel and making thermonuclear weapons relatively easy to deploy.
  • It had a maximum predicted yield of only 6 megatons — so it was 250% as explosive than was expected.
  • And, of course, it became famous for raining nuclear fallout down on inhabited islands over a hundred miles downwind, and exposing a crew of Japanese fishermen to fatal levels of radiation.

It was this latter event that made BRAVO famous — so famous that the United States had to admit publicly it had a hydrogen bomb. And accidentally exposing the Japanese fishing supply to radiation, less than a decade after Hiroshima and Nagasaki, has a way of making the Japanese people understandably upset. So the shot led to some almost frank discussion about what fallout meant — that being out of the direct line of fire wasn’t actually good enough.

Animation showing the progression of BRAVO's fallout exposure, at 1, 3, 6, 12, and 18 hours. Original source.

Animation showing the progression of BRAVO’s fallout exposure, at 1, 3, 6, 12, and 18 hours. Original source.

I say “almost frank” because there was some distinct lack of frankness about it. Lewis Strauss, the secrecy-prone AEC Chairman at the time and an all-around awful guy, gave some rather misleading statements about the reasons for the accident and its probable effects on the exposed native populations. His goal was reassurance, not truth. But, as with so many things in the nuclear age, the narrative got out of his control pretty quickly, and the fear of fallout was intensified whether he wanted it to be or not.

We now know that the Marshallese suffered quite a lot of long-term harm from the exposures, and that the contaminated areas were contaminated for a lot longer than the AEC guessed they would be. Some of this discrepancy comes from honest ignorance — the AEC didn’t know what they didn’t know about fallout. But a lot of it also came from a willingness to appear on top of the situation, when the AEC was anything but.

"Jabwe, the Rongelap health practitioner, assists Nurse Lt. M. Smith and Dr. Lt. J. S. Thompson, during a medical examination on Kwajalein, 11 March 1954." From DTRIAC SR-12-001.

“Jabwe, the Rongelap health practitioner, assists Nurse Lt. M. Smith and Dr. Lt. J. S. Thompson, during a medical examination on Kwajalein, 11 March 1954.” From DTRIAC SR-12-001.

I’ve been interested in BRAVO lately because I’ve been interested in fallout. It’s no secret that I’ve been working on a big new NUKEMAP update (I expect it to go live in a month or so) and that fallout is but one of the new amazing features that I’m adding. It’s been a long-time coming, since I had originally wanted to add a fallout model a year ago, but it turned out to be a non-trivial thing to implement. It’s not hard to throw up a few scaled curves, but coming up with a model that satisfies the aesthetic needs of the general NUKEMAP user base (that is, the people who want it to look impressive but aren’t interested in the details) and also has enough technical chops so that the informed don’t just immediately dismiss it (because I care about you, too!) involved digging up some rather ancient fallout models from the Cold War (even going out to the National Library of Medicine to get one rare one in its original paper format) and converting them all to Javascript so they can run in modern web browsers. But I’m happy to say that as of yesterday, I’ve finally come up with something that I’m pleased with, and so I can now clean up my Beautiful Mind-style filing system from my office and living room.

Why yes, you can

The most famous version of BRAVO’s total-dose exposure contours, from Glasstone and Dolan. It looks great on a mug, by the way.

Recently I was sent a PDF of a recent report (January 2013) by the Defense Threat Reduction Information Analysis Center (DTRIAC) that looked back on the history of BRAVO. It doesn’t seem to be easily available online (though it is unclassified), so I’ve posted it here: “Castle Bravo: Fifty Years of Legend and Lore (DTRIAC SR-12-001).” I haven’t had time to read the whole thing, but skipping around has been rewarding — it takes a close look at the questions of fallout prediction, contamination, and several “myths” that have circulated since 1954. It notes that the above fallout contour plot, for example, was originally created by the USAF Air Research and Development Command (ARDC), and that “it is unfortunate that this illustration has been so widely distributed, since it is incorrect.” The plume, they explain, actually under-represents the extent of the fallout — the worst of the fallout went further and wider than in the above diagram.

You can get a sense of the variation by looking at some of the other plots created of the BRAVO plume:

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

BRAVO fallout contours produced by the Armed Forces Special Weapons Project, Naval Radiological Defense Laboratory, and the RAND Corporation. Source. Click image to enlarge.

The AFSWP diagram on the left is relatively long and narrow; the NRDL one in the middle is fat and horrible. The RAND one at the right is something of a compromise. All three, though, show the fallout going further than the ADRC model — some 50-100 miles further. On the open ocean that doesn’t matter so much, but apply that to a densely populated part of the world and that’s pretty significant!

DTRIAC SR-12-001 is also kind of amazing in that it has a lot of photographs of BRAVO and the Castle series that I’d never seen before, some of which you’ll see around this post. One of my favorites is this one, of Don Ehlher (from Los Alamos) and Herbert York (from Livermore) in General Clarkson’s briefing room on March 17, 1954, with little mockups of the devices that were tested in Operation Castle:

Ehler and York - Operation Castle devices

There’s nothing classified there — the shapes of the various devices have long been declassified — but it’s still kind of amazing to see of their bombs on the table, as it were. They look like thermoses full of coffee. (The thing at far left might be a cup of coffee, for all that I can tell —  unfortunately the image quality is not great.)

It also has quite a lot of discussion of several persistent issues regarding the exposure of the Japanese crew and the Marshallese natives. I didn’t see anything especially new here, other than the suggestion that the fatality from the Fortunate Dragon fishing boat might have been at least partially because of the very aggressive-but-ineffective treatment regime prescribed by the Japanese physicians, which apparently included the very dubious procedure of repeatedly drawing his blood and then re-injecting it into muscle tissue. I don’t know enough of the details to know what to think of that, but at least they do a fairly good job of debunking the notion that BRAVO’s contamination of the Marshallese was deliberate. I’ve seen that floating around, even in some fairly serious forums and publications, and it’s just not supported by real evidence.

Castle BRAVO, 62 seconds after detonation. "This image was take at a distance of 50 [nautical miles] north GZ from an altitude of 10,000 feet. The lines running upward to the left of the stem and below the fireball are smoke trails from small rockets. At this time the cloud stem was about 4 mi in diameter." From DTRIAC SR-12-001.

Castle BRAVO, 62 seconds after detonation. “This image was take at a distance of 50 [nautical miles] north GZ from an altitude of 10,000 feet. The lines running upward to the left of the stem and below the fireball are smoke trails from small rockets. At this time the cloud stem was about 4 mi in diameter.” From DTRIAC SR-12-001.

One thing that I hadn’t appreciated as well before is that BRAVO is pretty much a worst-case scenario from a radiological point of view. It was a very high-yield weapon that was very “dirty” right out of the box: 10 of its 15 megatons (67%) were from fission.1

It was detonated as a surface burst, which automatically means quite a significant fallout problem. Nuclear weapons that detonate so that their fireball does not come into contact with the ground release “militarily insignificant” amounts of fallout, even if their yields are very high. (They are not necessarily “humanly insignificant” amounts, but they are far, far, far less than surface bursts — it is not a subtle difference.2 )

But even worse, it was a surface burst in a coral reef, which is just a really, really bad idea. Detonating nuclear weapons on a desert floor, like in Nevada, still presents significant fallout issues. But a coral reef is really an awful place to set them off, and not just because coral reefs are awesome and shouldn’t be blown up. They are an ideal medium for creating and spreading contamination: they break apart with no resistance, but do so in big enough chunks that they rapidly fall back to Earth. Particle size is a big deal when it comes to fallout; small particles go up with the fireball and stay aloft long enough to lose most of their radioactive energy and diffuse into the atmosphere, while heavy particles fall right back down again pretty quickly, en masse. So blowing up and irradiating something like coral is just the worst possible thing.3

Castle BRAVO, 16 minutes after detonation, seen from a distance of 50 nautical miles, at an altitude of 10,000 feet. From DTRIAC SR-12-001.

Castle BRAVO, 16 minutes after detonation, seen from a distance of 50 nautical miles, at an altitude of 10,000 feet. From DTRIAC SR-12-001.

Note that the famous 50 Mt “Tsar Bomba” lacked a final fission stage and so only 3% of its total yield — 1.5 Mt — was from fission. So despite the fact that the Tsar Bomba was 3.3 times as explosive than Castle Bravo, it had almost 7 times fewer fission products. And its fireball never touched the ground (in fact, it was reflected upwards by its own shock wave, which is kind of amazing to watch), so it was a very “clean” shot radiologically. The “full-sized,” 100 Mt Tsar Bomba would have been 52% fission — a very dirty bomb indeed.

In the end, what I’ve come to take away from BRAVO is that it actually was a mistake even more colossal than one might have originally thought. It was a tremendously bad idea from a human health standpoint, and turned into a public relations disaster that the Atomic Energy Commission never really could kick. 

In retrospect the entire “event” seems to have been utterly avoidable as a radiological disaster, even with all of the uncertainties about yield and weather. It’s cliché to talk about nuclear weapons in terms of playing with “forces of nature beyond our comprehension,” but I’ve come to feel that BRAVO is a cautionary tale about hubris and incompetence in the nuclear age — scientists setting off a weapon whose size they did not know, whose effects they did not correctly forecast, whose legacy will not soon be outlived.

  1. Chuck Hansen, Swords of Armageddon, IV-299. []
  2. The count difference is about three orders of magnitude or so less, judging by shots like Redwing CHEROKEE. That’s still a few rads, but the difference between 1,000 and 1 rad/hr is pretty significant. []
  3. Couldn’t they have foreseen this? In theory, yes — they had already blown up a high-yield, “dirty” fission hydrogen bomb on a coral reef in 1952, the MIKE test. But somewhere a number of AEC planners seem to have gotten their wires crossed, because a lot of them thought that MIKE had very little fallout, when in fact it also produced a lot of very similar contamination. Unlike BRAVO, however, MIKE’s fallout blew out over open sea. The only radiation monitoring seems to have been done on the islands, and so they don’t seem to have ever drawn up one of those cigar-shaped plumes for it. See e.g. the discussion here on page 51. []