Posts Tagged ‘Nuclear testing’

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. []
Visions

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.

Notes
  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. []
Meditations

Kilotons per kilogram

Monday, December 23rd, 2013

Nuclear weapons can be made to have pretty much as much of a bang as one wants to make them, but with increased explosive yield comes an increased weapon weight. We always talk vaguely about being able to make H-bombs to arbitrarily high yields, but recently I’ve been mulling over this fact somewhat quantitatively. I gave a talk last month at the History of Science Society Meeting on US interest in 50-100 MT bombs around the time of the Limited Test Ban Treaty, and while working on this paper I got  slightly obsessed with what is known as the yield-to-weight ratio.

Little Boy — a big bang compared to a conventional bomb, but still a very crude nuclear bomb.

Little Boy — a big bang compared to a conventional bomb, but still a very crude nuclear bomb.

What makes nuclear weapons impressive and terrible is that their default yield-to-weight ratio — that is, the amount of bang per mass, usually expressed in terms of kilotons per kilogram (kt/kg) — is much, much higher than conventional explosives. Take TNT for example. A ton of TNT weighs, well, a ton. By definition. So that’s 0.001 kilotons per 1,000 kilograms; or 0.000001 kt/kg. By comparison, even a crude weapon like the Little Boy bomb that was dropped on Hiroshima was about 15 kilotons in a 4,400 kg package: 0.003 kt/kg. That means that the Little Boy bomb had an energy density three orders of magnitude higher than a regular TNT bomb would. Now, TNT isn’t the be-all and end-all of conventional explosives, but no conventional explosive gets that much boom for its buck compared to a nuke.

The Little Boy yield is much lower than the hypothetical energy density of uranium-235. For every kilogram of uranium-235 that completely fissions, it releases about 17 kt/kg. That means that less than a kilogram of uranium-235 fissioned in the Little Boy bomb to release its 15 kilotons of energy. Knowing that there was 64 kg of uranium in the bomb, that means that something like 1.3% of the uranium in the weapon actually underwent fission. So right off the bat, one could intuit that this is something that could probably be improved upon.

Fat Man — a lot better use of fissile material than Little Boy, but no more efficient in terms of yield-to-weight.

Fat Man — a lot better use of fissile material than Little Boy, but no more efficient in terms of yield-to-weight.

The Fat Man bomb had a much better use of fissile material than Little Boy. Its yield wasn’t that much better (around 20 kilotons), but it managed to squeeze that (literally) out of only 6.2 kilograms of plutonium-239. Pu-239 releases around 19 kilotons per kilogram that completely fissions, so that means that around 15% of the Fat Man core (a little under 1 kg of plutonium) underwent fission. But the bomb itself still weighed 4,700 kg, making its yield-to-weight ratio a mere 0.004 kt/kg. Why, despite the improve efficiency and more advanced design of Fat Man, was the yield ratio almost identical to Little Boy? Because in order to get that 1 kg of fissioning, it required a very heavy apparatus. The explosive lenses weighed something like 2,400 kilograms just by themselves. The depleted uranium tamper that held the core together and reflected neutrons added another 120 kilograms.  The aluminum sphere that held the whole apparatus together weighed 520 kilograms. The ballistic case (a necessary thing for any actual weapon!) weighed another 1,400 kg or so. All of these things were necessary to make the bomb either work, or be a droppable bomb.

So it’s unsurprising to learn that improving yield-to-weight ratios was a high order of business in the postwar nuclear program. Thermonuclear fusion ups the ante quite a bit. Lithium-deuteride (LiD), the most common and usable fusion fuel, yields 50 kilotons for every kilogram that undergoes fusion — so fusion is nearly 3 times more energetic per weight than fission. So the more fusion you add to a weapon, the better the yield-to-weight ratio, excepting for the fact that all fusion weapons require a fission primary and usually also have very heavy tampers.

I took all of the reported American nuclear weapon weights and yields from Carey Sublette’s always-useful website, put them into the statistical analysis program R, and created this semi-crazy-looking graph of American yield-to-weight ratios:

Yield-to-weight ratios of US nuclear weapons

The horizontal (x) axis is the yield in kilotons (on a logarithmic scale), the vertical (y) axis is the weight in kilograms (also on a log scale). In choosing which of the weights and yields to use, I’ve always picked the lowest listed weights and the highest listed yields — because I’m interested in the optimal state of the art. The individual scatter points represent models of weapons. The size of each point represents how many of them were produced; the color of them represents when they were first deployed. Those with crosses over them are still in the stockpile. The diagonal lines indicate specific yield-to-weight ratio regions.

A few points of interest here. You can see Little Boy (Mk-1), Fat Man (Mk-3), and the postwar Fat Man improvements (Mk-4 — same weight, bigger yield) at the upper left, between 0.01 kt/kg and 0.001 kt/kg. This is a nice benchmark for fairly inefficient fission weapons. At upper right, you can see the cluster of the first H-bomb designs (TX-16, EC-17, Mk-17, EC-24, Mk-24) — high yield (hence far to the right), but very heavy (hence very high). Again, a good benchmark for first generation high-yield thermonuclear weapons.

What a chart like this lets you do, then, is start to think in a really visual and somewhat quantitative way about the sophistication of late nuclear weapon designs. You can see quite readily, for example, that radical reductions in weight, like the sort required to make small tactical nuclear weapons, generally results in a real decrease in efficiency. Those are the weapons in the lower left corner, pretty much the only weapons in the Little Boy/Fat Man efficiency range (or worse). One can also see that there are a few general trends in design development over time if one looks at how the colors trend.

First there is a movement down and to the right (less weight, more yield — improved fission bombs); there is also a movement sharply up and to the right (high weight, very high yield — thermonuclear weapons) which then moves down and to the left again (high yield, lower weight — improved thermonuclear weapons). There is also the splinter of low-weight, low-yield tactical weapons as well that jots off to the lower left. In the middle-right is what appears to be a sophisticated “sweet spot,” the place where all US weapons currently in the stockpile end up, in the 0.1-3 kt/kg range, especially the 2-3 kt/kg range:

Yield-to-weight ratios -- trends

These are the bombs like the W-76 or the B-61 — bombs with “medium” yield warheads (100s rather than 1,000s of kilotons) in relatively low weight packages (100s rather than 1000s of kilograms). These are the weapons take advantage of the fact that they are expected to be relatively accurate (and thus don’t need to be in the multi-megaton range to have strategic implications), along with what are apparently sophisticated thermonuclear design tricks (like spherical secondaries) to squeeze a lot of energy out of what is a relatively small amount of material. Take the W-76 for example: its manages to get 100 kilotons of yield out of 164 kilograms. If we assume that it is a 50/50 fission to fusion ratio, that means that it manages to fully fission about 5 kilograms of fissionable material, and to fully fuse about 2 kilograms of fusionable material. And it takes just 157 kg of other apparatus (and unfissioned or unfused material) to produce that result — which is just a little more than Shaquille O’Neal weighs.

Such weapons aren’t the most efficient. Weapon designer Theodore Taylor wrote in 1987 that 6 kiloton/kilogram had been pretty much the upper limit of what had even been achieved.1 Only a handful of weapons got close to that. The most efficient weapon in the US stockpile was the Mk-41, a ridiculously high yield weapon (25 megatons) that made up for its weight with a lot of fusion energy.

The components of the B-61 nuclear weapon — the warhead is the bullet-shape in the mid-left. The B-61 was designed for flexibility, not miniaturization, but it's still impressive that it could get 20X the Hiroshima bomb's output out of that garbage-can sized warhead.

The components of the B-61 nuclear weapon — the warhead is the bullet-shape in the mid-left. The B-61 was designed for flexibility, not miniaturization, but it’s still impressive that it could get 20X the Hiroshima bomb’s output out of that garbage-can sized warhead.

But given that high efficiency is tied to high yields — and relatively high weights — it’s clear that the innovations that allowed for the placing of warheads on MIRVed, submarine-launched platforms are still pretty impressive. The really magical range seems to be for weapons that in the hundred kiloton range (more than 100 kilotons but under a megaton), yet under 1,000 kilograms. Every one of those dates from after 1962, and probably involves the real breakthroughs in warhead design that were first used with the Operation Dominic  test series (1962). This is the kind of strategic miniaturization that makes war planners happy.

What’s the payoff of thinking about these kinds of numbers? One is that it allows you to see where innovations have been made, even if you know nothing about how the weapon works. In other words, yield-to-weight ratios can provide a heuristic for making sense of nuclear design sophistication, comparing developments over time without caring about the guts of the weapon itself. It also allows you to make cross-national comparisons in the same fashion. The French nuclear arsenal apparently developed weapons in that same miniaturized yield-to-weight range of the United States by the 1970s — apparently with some help from the United States — and so we can probably assume that they know whatever the United States figured out about miniaturized H-bomb design in the 1960s.

The Tsar Bomba: a whole lot of boom, but a whole lot of weight. The US thought they could make the same amount of boom for half the weight.

The Tsar Bomba: a whole lot of boom, but a whole lot of weight. The US thought they could make the same amount of boom for half the weight.

Or, to take another tack, and returning to the initial impetus for me looking at this topic, we know that the famous “Tsar Bomba” of the Soviet Union weighed 27,000 kilograms and had a maximum yield of 100 Mt, giving it a yield-to-weight ratio of “only” 3.43 kilotons/kilograms. That’s pretty high, but not for a weapon that used so much fusion energy. It was clear to the Atomic Energy Commission that the Soviets had just scaled up a traditional H-bomb design and had not developed any new tricks. By contrast, the US was confident in 1961 that they could make a 100 Mt weapon that weighed around 13,600 kg (30,000 lb) — an impressive 7.35 kiloton/kilogram ratio, something well above the 6 kt/kg achieved maximum. By 1962, after the Dominic series, they thought they might be able to pull off 50 Mt in only a 4,500 kg (10,000 lb) package — a kind of ridiculous 11 kt/kg ratio. (In this estimate, they noted that the weapon might have an impractically large diameter as a result, perhaps because the secondary was spherical as opposed to cylindrical.) So we can see, without really knowing much about the US had in mind, that it was planning something very, very different from what the Soviets set off.

It’s this black box approach that I find so interesting about these ratios. It’s a crude tool, to be sure, but a tool nonetheless. By looking at the broad trends, we get insights into the specifics, and peel back the veil just a tiny bit.

Notes
  1. Theodore B. Taylor, ”Third Generation Nuclear Weapons,” Scientific American 256, No. 4 (April 1987), 30-39, on 34: “The yield-to-weight ratios of pure fission warheads have ranged from a low of about .0005 kiloton per kilogram to a high of about .1 kiloton per kilogram. [...] The overall yield-to-weight ratio of strategic thermonuclear warheads has been as high as about six kilotons per kilogram. Although the maximum theoretical ratios are 17 and 50 kilotons per kilogram respectively for fission and fusion reactions, the maximum yield-to-weight ratio for U.S. weapons has probably come close to the practical limit owing to various unavoidable inefficiencies in nuclear weapon design (primarily arising from the fact that it is impossible to keep the weapon from disintegrating before complete fission or fusion of the nuclear explosive has taken place.” []
Visions

Art, Destruction, Entropy

Friday, December 13th, 2013

Are nuclear explosions art? Anyone who has taken even a glance into modern and contemporary art knows that the official mantra might as well be “anything goes,” but I found myself wondering this while visiting the exhibition “Damage Control: Art and Destruction since 1950” that is currently at the Hirshhorn Museum. The first thing one sees upon entering is a juxtaposition of two very different sorts of “work.” On the right is a fairly long loop of EG&G footage of nuclear test explosions, broadcast in high definition over an entirety of a wall. On the left is a piano that has been destroyed with an axe. This, I thought, is at least a provocative way to start things off.

Edgerton, Germeshausen, and Grier (EG&G) was a contractor for the federal government during the Cold War, responsible for documenting nuclear test explosions. Quite a lot of the famous Cold War nuclear detonation footage was taken by EG&G. They are perhaps most famous for their “Rapatronic” photographs, the ultimate expression of MIT engineer Harold “Doc” Edgerton’s work of slowing down time through photography, but this was only a part of their overall contribution. The film they have at the Hirshhorn is something of an EG&G “greatest hits” reel from the 1950s, and its affect on the others in the audience was palpable. Adults and children alike were drawn to the blasts, displayed one after another without commentary or explanation.1 Their reactions didn’t strike me as one of disgust or horror, but of amazement and awe. Most of the footage was from the Nevada Test Site, so the bombs were generally just blowing up desert scrub, and occasionally houses constructed for effects testing.

The destroyed piano, by contrast, got reactions of shock and disgust. It was the remains of a piece of performance art conducted by Raphael Montañez Ortiz, one of several he’s done, apparently. My wife, a piano player and a nuclear historian, also found it disturbing. “If you know what goes into making a piano…,” she started to say. “But then again, if you know what goes into making a city…,” she caught herself. I overheard other people say similar things.

The difference in reactions isn’t too surprising — it’s a common theme that it is easy to appreciate the destruction of something at a human scale, difficult to appreciate it at the scale of nuclear bomb. A lot of what I’ve spent time doing, with the NUKEMAP and my writing, is to try to understand, and to impart, the scale of a nuclear explosion. A lot of this has involved looking at the attempts of others, as well, from official Cold War visualizations made for secret committees to popular films, as they have tried to communicate this to their target audiences. The hardest thing is that our brains appear only to be wired for empathy at the individual level, and don’t readily apply it to large groups or large areas. The best work in these areas conveys both the broad scope of destruction, but then ties it into the personal. They individualize the experience of mass ruination.

And the EG&G footage isn’t trying to do that. It was data meant for very specific technical purposes. It was developed in order to further the US nuclear program, and defense against Soviet nuclear weapons. Which is why I somewhat question its inclusion, or, at least, its decontextualization. It is art only in the sense that it has aesthetics and it has been put into an art gallery. One can read into it whatever one wants, of course, but it wasn’t created to have deep meaning and depth in that sense. (Whether one cares about authorial intention, of course, is its own can of modern art worms.) Just as a small example of what I mean, Andy Warhol famously made a print of mushroom clouds for his own “disaster” series (a few of which, but not this print, were featured in the exhibit):

"Atomic Bomb," Andy Warhol, 1965.

“Atomic Bomb,” Andy Warhol, 1965.

Now Warhol is a complicated character, but since he was explicitly an artist I think it is always fair game to talk about his possible intentions, the aesthetics of the piece, the deeper meanings, and so on. Warhol’s art has generally been interpreted to be about commercialization and commodification. The mushroom cloud in repetition becomes a statement about our culture and its fascination with mass destruction, perhaps. Coming in the mid-1960s, after the close-call terrors of the early years of the decade, perhaps it was maybe too-little too-late, but still, it has an ominous aesthetic appeal, perhaps now more than then.

Because I don’t think this image was widely circulated at the time, I doubt that Warhol knew that Berlyn Brixner, the Trinity test photographer, had made very similar sorts of images of the world’s first nuclear fireball at “Trinity”:

TR-NN-11, Berlyn Brixner, 1945.

“TR-NN-11,” Berlyn Brixner, 1945.

Brixner appreciated the aesthetics and craft of his work, to be sure. But the above photograph is explicitly a piece of technical data. It is designed to show the Trinity fireball’s evolution over the 15-26 millisecond range. Warhol’s instrument of choice was the silkscreen printer; Brixner’s was the 10,000 fps “Fastax” camera. There’s a superficial similarity in their atomic repetition. You could make a statement by putting them next to each other — as I am doing here! — but properly understood, I think, they are quite different sorts of works.

Don’t get me wrong. Re-appropriating “non-art” into “art” has been a common move over much of the 20th century at the very least. But the problem for me is not that people shouldn’t appreciate the aesthetics of the “non-art.” It’s that focusing on the aesthetics makes it easy to lose sight of the context. (As well as the craft — Brixner’s work was exponentially more difficult to produce than Warhol’s!) The EG&G footage in the exhibit doesn’t explain much of how, or why, it was made. It seems to be asking the viewer to appreciate it solely on its aesthetic grounds. Which I think is the real problem. Many of the tests they show resulted in significant downwind fallout for the populations near the Nevada Test Site. Many of them involved the development of new, ever-more elaborate ways of mass destruction. Many of them were the product of years of top scientific manpower, untold riches, and a deep political context. To appreciate them as simply big, bright booms robs them of something — no matter how aesthetically beautiful those big, bright booms actually are. 

Gustav Metzger's "auto-destructive" art.

Gustav Metzger’s “auto-destructive” art.

What makes it more ironic is that the exhibit actually does give considerable context to some of the works that are explicitly “art.” You have to explain the context of Gustav Metzger’s “auto-destructive” art — it involves him filming himself painting on canvases with a strong acid, so the artwork destroys itself in the process. Without the context there, what is left is just a boring, not-very-comprehensible movie of a man destroying a blank canvas. But anyway.

In terms of the audience at the exhibit, which was fairly well-attended when I was there with my wife, the most interesting part was the handling of children. The Smithsonian museums are of course explicitly places that people take their children while visiting the city, so it’s no surprise that you probably find more of them at the Hirshhorn than you would at MOMA or other similar institutions. But children add a level of anxiety to an exhibit about destruction. They were wowed by the wall-o’-bombs but not, it seemed, by the piano. Parents seemed to let them wander free through most of it, but there were several films where I saw kids get yanked out by their parents once the parents realized the content was going to be disturbing. In one of these films, the “disturbing” content was of a variety that might have been hard for the children to directly understand — the famous film of the Hindenburg going up in flame, for example, where the violence was real but seen from enough of a distance to keep you from seeing actual injuries or bodies. The one I saw the kids getting really removed from (by their parents, not the museum) was footage of the 2011 Vancouver riots. I wasn’t impressed too much with the footage itself (its content was interesting in a voyeuristic way, but there seemed to be nothing special about the filming or editing), but the immediacy of its violence was much more palpable than the violence-at-a-distance that one saw in most of the other such works. It’s cliche to trot out that old quote attributed (probably wrongly) to Stalin that one death is a tragedy, a million is a statistic, but there’s something deeply true to it about how we perceive violence and pain.

Damage Control exhibit site

There are a lot of works in the exhibit. As one would expect, some hew to the theme very closely, some are a bit more tenuous. Overall, though, it was pretty interesting, and if you’re in town, you ought to check it out. The original comment my wife made about pianos and cities stuck with me as I looked at all of the various meditations on “destruction.” In it, I kept coming back to the second law of thermodynamics. On the face of it, it is a very clinical, statistical law: “the entropy of an isolated system never decreases.” It is actually quite profound, something that the 19th-century physicists who developed it knew. Entropy can be broadly understood as “disorder.” The second law of thermodynamics says, in essence, that without additional energy being put into it, everything eventually falls apart. It takes work to keep things “organized,” whether they are apartments, bodies, or cities.2 Ludwig Boltzmann, who helped formulate the law, stated gnomically in 1886 that:

The general struggle for existence of animate beings is not a struggle for raw materials – these, for organisms, are air, water and soil, all abundantly available – nor for energy, which exists in plenty in any body in the form of heat Q, but of a struggle for [negative] entropy, which becomes available through the transition of energy from the hot sun to the cold earth.

In other words, life itself is a struggle against entropy. Our bodies are constantly taking disordered parts of the world (heat energy, for example, and the remains of other living things) and using them to fuel the work of keeping us from falling apart.

But the other way to think about this law is that generally it is easier to take things apart than it is to keep them together. It is easier to convert a piano into a low-energy state (through an axe, or perhaps a fire) than it is to make a piano in the first place. It is easier to destroy a city than it is to make a city. The three-year effort of the half-a-million people on the Manhattan Project was substantial, to be sure, but still only a fraction of the work it took to make the cities of Hiroshima and Nagasaki, and all that they contained, biological and material, in the first place.

Of course, the speed at which entropy increases is often controllable. The universe will eventually wear out — but not for a long time. Human civilization will necessarily go extinct — but it doesn’t have to happen anytime soon. What hits home with the “Damage Control” exhibit is how we as a species have to work so hard to keep everything together, while simultaneously working so hard to find ways to make everything fall apart. And in this, perhaps, it is a success, even if I left with many niggling questions about the presentation of some of the works in particular.

Notes
  1. Various guys in the audience would occasionally try to give explanation to their loved ones, and they were generally incorrect, alas. “That must be at Alamogordo… That’s got to be an H-bomb…” no, no, no. Of course, I was there with my wife, and I was talking up my own little storm (though less loudly than the wrong guys), but at least I know my stuff for the most part… []
  2. The key, confusing part about the second law is the bit about the “isolated system.” It doesn’t say that entropy always increases. It says that in an isolated system — that is, a system with no energy being input into it — entropy always increases. For our planet, the Sun is the source of that input, and you can trace, through a long series of events, its own negative entropy to the Big Bang itself. []
Meditations

Liminal 1946: A Year in Flux

Friday, November 8th, 2013

There are lots of important and exciting years that people like to talk about when it comes to the history of nuclear weapons. 1945 obviously gets pride of place, being the year of the first nuclear explosion ever (Trinity), the first  and only uses of the weapons in war (Hiroshima and Nagasaki), and the end of World War II (and thus the beginning of the postwar world). 1962 gets brought up because of the Cuban Missile Crisis. 1983 has been making a resurgence in our nuclear consciousness, thanks to lots of renewed interest in the Able-Archer war scare. All of these dates are, of course, super important.

Washington Post - January 1, 1946

But one of my favorite historical years is 1946. It’s easy to overlook — while there are some important individual events that happen, none of them are as cataclysmic as some of the events of the aforementioned years, or even some of the other important big years. But, as I was reminded last week while going through some of the papers of David Lilienthal and Bernard Baruch that were in the Princeton University archives, 1946 was something special in and of itself. It is not the big events that define 1946, but the fact that it was a liminal year, a transition period between two orders. For policymakers in the United States, 1946 was when the question of “what will the country’s attitude towards the bomb be?” was still completely up for grabs, but over the course of the year, things became more set in stone.

1946 was a brief period when anything seemed possible. When nothing had yet calcified. The postwar situation was still fluid, and the American approach towards the bomb still unclear.

Part of the reason for this is because things went a little off the rails in 1945. The bombs were dropped, the war had ended, people were pretty happy about all of that. General Groves et al. assumed that Congress would basically take their recommendations for how the bomb should be regarded in the postwar (by passing the May-Johnson Bill, which military lawyers, with help from Vannevar Bush and James Conant, drafted in the final weeks of World War II). At first, it looked like this was going to happen — after all, didn’t Groves “succeed” during the war? But in the waning months of 1945, this consensus rapidly deteriorated. The atomic scientists on the Manhattan Project who had been dissatisfied with the Army turned out to make a formidable lobby, and they found allies amongst a number of Senators. Most important of these was first-term Senator Brien McMahon, who quickly saw an opportunity to jump into the limelight by making atomic energy his issue. By the end of the year, not only did Congressional support fall flat for the Army’s Bill, but even Truman had withdrawn support for it. In its place, McMahon suggested a bill that looked like something the scientists would have written — a much freer, less secret, civilian-run plan for atomic energy.

So what happened in 1946? Let’s just jot off a few of the big things I have in mind.

January: The United Nations meets for the first time. Kind of a big deal. The UN Atomic Energy Commission is created to sort out questions about the future of nuclear technology on a global scale. Hearings on the McMahon Bill continue in Congress through February.

Igor Gouzenko (masked) promoting a novel in 1954. The mask was to help him maintain his anonymity, but you have to admit it adds a wonderfully surreal and theatrical aspect to the whole thing.

Igor Gouzenko (masked) promoting a novel in 1954. The mask was to help him maintain his anonymity, but you have to admit it adds a wonderfully surreal and theatrical aspect to the whole thing.

February: The first Soviet atomic spy ring is made public when General Groves leaks information about Igor Gouzenko to the press. Groves wasn’t himself too concerned about it — it was only a Canadian spy ring, and Groves had compartmentalized the Canadians out of anything he considered really important — but it served the nice purpose of dashing the anti-secrecy lobby onto the rocks.

Also in February, George F. Kennan sends his famous “Long Telegram” from Moscow, arguing that the Soviet Union sees itself in essential, permanent conflict with the West and is not likely to liberalize anytime soon. Kennan argues that containment of the USSR through “strong resistance” is the only viable course for the United States.

March: The Manhattan Engineer District’s Declassification Organization starts full operation. Groves had asked the top Manhattan Project scientists to come up with the first declassification rules in November 1945, when he realized that Congress wasn’t going to be passing legislation as soon as he expected. They came up with the first declassification procedures and the first declassification guides, inaugurating the first systematic approach to deciding what was secret and what was not.

Lilienthal's own copy of the mass-market edition of the Acheson-Lilienthal Report, from the Princeton University Archives.

Lilienthal’s own copy of the mass-market edition of the Acheson-Lilienthal Report, from the Princeton University Archives.

March: The Acheson-Lilienthal Report is completed and submitted, in secret, to the State Department. It is quickly leaked and then was followed up by a legitimate publication by the State Department. Created by a sub-committee of advisors, headed by TVA Chairman David Lilienthal and with technical advice provided by J. Robert Oppenheimer, the Acheson-Lilienthal Report argued that the only way to a safe world was through “international control” of atomic energy. The scheme they propose is that the United Nations create an organization (the Atomic Development Authority) that would be granted full control over world uranium stocks and would have the ability to inspect all facilities that used uranium in significant quantities. Peaceful applications of atomic energy would be permitted, but making nuclear weapons would not be. If one thought of it as the Nuclear Non-Proliferation Treaty, except without any authorized possession of nuclear weapons, one would not be too far off the mark. Of note is that it is an approach to controlling the bomb that is explicitly not about secrecy, but about physical control of materials. It is not loved by Truman and his more hawkish advisors (e.g. Secretary of State Byrnes), but because of its leak and subsequent publication under State Department header, it is understood to be “the” position of the United States government on the issue.

April: The McMahon Act gets substantial modifications while in committee, including the creation of a Military Liaison Committee (giving the military an official position in the running of the Atomic Energy Commission) and the introduction of a draconian secrecy provision (the “restricted data” concept that this blog takes its name from).

June: The Senate passes the McMahon Act. The House starts to debate it. Several changes are made to the House version of the bill — notably all employees with access to “restricted data” must now be investigated by the FBI and the penalty for misuse or espionage of “restricted data” is increased to death or life imprisonment. Both of these features were kept in the final version submitted to the President for signature in July.

June: Bernard Baruch, Truman’s appointee to head the US delegation of the UN Atomic Energy Commission, presents a modified form of the Acheson-Lilienthal Report to the UNAEC, dubbed the Baruch Plan. Some of the modifications are substantial, and are deeply resented by people like Oppenheimer who see them as torpedoing the plan. The Baruch Plan, for example, considered the question of what to do about violations of the agreement something that needed to be hashed out explicitly and well in advance. It also argued that the United States would not destroy its (still tiny) nuclear stockpile until the Soviet Union had proven it was not trying to build a bomb of their own. It was explicit about the need for full inspections of the USSR — a difficulty in an explicitly closed society — and stripped the UN Security Council of veto power when it came to enforcing violations of the treaty. The Soviets were, perhaps unsurprisingly, resistant to all of these measures. Andrei Gromyko proposes a counter-plan which, like the Baruch Plan, prohibits the manufacture and use of atomic weaponry. However, it requires full and immediate disarmament by the United States before anything else would go into effect, and excludes any international role in inspection or enforcement: states would self-regulate on this front.

Shot "Baker" of Operation Crossroads — one of the more famous mushroom clouds of all time. Note that the mushroom cloud itself is not the wide cloud you see there (which is a brief condensation cloud caused by it being an underwater detonation), but is the more bulbous cloud you see peaking out of the top of that cloud. You can see the battleships used for target practice near base of the cloud. The dark mark on the right side of the stem may be an upturned USS Arkansas.

Shot “Baker” of Operation Crossroads — one of the more famous mushroom clouds of all time. Note that the mushroom cloud itself is not the wide cloud you see there (which is a brief condensation cloud caused by it being an underwater detonation), but is the more bulbous cloud you see peaking out of the top of that cloud. You can see the battleships used for target practice near base of the cloud. The dark mark on the right side of the stem may be an upturned USS Arkansas.

July: The first postwar nuclear test series, Operation Crossroads, begins in the Bikini Atoll, Marshall Islands. Now this is a curious event. Ostensibly the United States was in favor of getting rid of nuclear weapons, and in fact had not yet finalized its domestic legislation about the bomb. But at the same time, it planned to set off three of them, to see their effect on naval vessels. (They decided to only set off two, in the end.) The bombs were themselves still secret, of course, but it was decided that this event should be open to the world and its press. Even the Soviets were invited! As one contemporary report summed up:

The unique nature of the operation was inherent not only in its huge size — the huge numbers of participating personnel, and the huge amounts of test equipment and number of instruments involved — it was inherent also in the tremendous glare of publicity to which the tests were exposed, and above all the the extraordinary fact that the weapons whose performance was exposed to this publicity were still classified, secret, weapons, which had never even been seen except by a few men in the inner circles of the Manhattan District and by those who had assisted in the three previous atomic bomb detonations. It has been truly said that the operation was “the most observed, most photographed, most talked-of scientific test ever conducted.” Paradoxically, it may also be said that it was the most publicly advertised secret test ever conducted.1

August: Truman signs the McMahon Act into law, and it becomes the Atomic Energy Act of 1946. It stipulates that a five-person Atomic Energy Commission will run all of the nation’s domestic atomic energy affairs, and while half of the law retains the “free and open” approach of the early McMahon Act, the other half has a very conservative and restrictive flavor to it, promising death and imprisonment to anyone who betrays atomic secrets. The paradox is explicit, McMahon explained at the time, because finding a way to implement policy between those two extremes would produce rational discussion. Right. Did I mention he was a first-term Senator? The Atomic Energy Commission would take over from the Manhattan Engineer District starting in 1947.

A meeting of the UN Atomic Energy Commission in October 1946. Bernard Baruch is the white-haired man sitting at the table at right behind the “U.S.A” plaque. At far top-right of the photo is Robert Oppenheimer. Two people above Baruch, in the very back, is General Groves. Directly below Groves is Manhattan Project scientist Richard Tolman. British physicist James Chadwick sits directly behind the U.K. representative at the table.

A meeting of the UN Atomic Energy Commission in October 1946. At front left, speaking, is Andrei Gromyko. Bernard Baruch is the white-haired man sitting at the table at right behind the “U.S.A” plaque. At far top-right of the photo is a pensive J. Robert Oppenheimer. Two people above Baruch, in the very back, is a bored-looking General Groves. Directly below Groves is Manhattan Project scientist Richard Tolman. British physicist James Chadwick sits directly behind the U.K. representative at the table.

September: Baruch tells Truman that international control of atomic energy seems nowhere in sight. The Soviet situation has soured dramatically over the course of the year. The Soviets’  international control plan, the Gromyko Plan, requires full faith in Stalin’s willingness to self-regulate. Stalin, for his part, is not willing to sign a pledge of disarmament and inspection while the United States is continuing to build nuclear weapons. It is clear to Baruch, and even to more liberal-minded observers like Oppenheimer, that the Soviets are probably not going to play ball on any of this, because it would not only require them to forswear a potentially important weapon, but because any true plan would require them to become a much more open society.

October: Truman appoints David Lilienthal as the Chairman of the Atomic Energy Commission. Lilienthal is enthusiastic about the job — a New Deal technocrat, he thinks that he can use his position to set up a fairly liberal approach to nuclear technology in the United States. He is quickly confronted by the fact that the atomic empire established by the Manhattan Engineer District has decayed appreciably in year after the end of the war, and that he has powerful enemies in Congress and in the military. His confirmation hearings start in early 1947, and are exceptionally acrimonious. I love Lilienthal as an historical figure, because he is an idealist who really wants to accomplish good things, but ends up doing almost the opposite of what he set out to do. To me this says a lot about the human condition.

November: The US Atomic Energy Commission meets for the first time in Oak Ridge, Tennessee. They adopt the declassification system of the Manhattan District, among other administrative matters.

December: Meredith Gardner, a cryptanalyst for the US Army Signal Intelligence Service, achieves a major breakthrough in decrypting wartime Soviet cables. A cable from 1944 contains a list of scientists working at Los Alamos — indications of a serious breach in wartime atomic security, potentially much worse than the Canadian spy ring. This information is kept extremely secret, however, as this work becomes a major component in the VENONA project, which (years later) leads to the discovery of Klaus Fuchs, Julius Rosenberg, and many other Soviet spies.

On Christmas Day, 1946, the Soviet Union’s first experimental reactor, F-1, goes critical for the first time.

The Soviet F-1 reactor, in 2009. It remains operational today — the longest-lived nuclear reactor by far.

The Soviet F-1 reactor, in 2009. It remains operational today — the longest-lived nuclear reactor by far.

No single event on that list stands out as on par with Hiroshima, the Cuban Missile Crisis, or even the Berlin Crisis. But taken together, I think, the list makes a strong argument for the importance of 1946. When one reads the documents from this period, one gets this sense of a world in flux. On the one hand, you have people who are hoping that the re-ordering of the world after World War II will present an enormous opportunity for creating a more peaceful existence. The ideas of world government, of the banning of nuclear weapons, of openness and prosperity, seem seriously on the table. And not just by members of the liberal elite, mind you: even US Army Generals were supporting these kinds of positions! And yet, as the year wore on, the hopes began to fade. Harsher analysis began to prevail. Even the most optimistic observers started to see that the problems of the old order weren’t going away anytime soon, that no amount of good faith was going to get Stalin to play ball. Which is, I should say, not to put all of the onus on the Soviets, as intractable as they were, and as awful as Stalin was. One can imagine a Cold War that was less tense, less explicitly antagonistic, less dangerous, even with limitations that the existence of a ruler like Stalin imposed. But some of the more hopeful things seem, with reflection, like pure fantasy. This is Stalin we’re talking about, after all. Roosevelt might have been able to sweet talk him for awhile, but even that had its limits.

We now know, of course, that the Soviet Union was furiously trying to build its own atomic arsenal in secret during this entire period. We also know that the US military was explicitly expecting to rely on atomic weapons in any future conflict, in order to offset the massive Soviet conventional advantage that existed at the time. We know that there was extensive Soviet espionage in the US government and its atomic program, although not as extensive as fantasists like McCarthy thought. We also know, through hard experience, that questions of treaty violations and inspections didn’t go away over time — if anything, I think, the experience of the Nuclear Non-Proliferation Treaty has shown that many of Baruch’s controversial changes to the Acheson-Lilienthal Report were pretty astute, and quickly got to the center of the political difficulties that all arms control efforts present.

As an historian, I love periods of flux and of change. (As an individual, I know that living in “interesting times” can be pretty stressful!) I love looking at where old orders break down, and new orders emerge. The immediate postwar is one such period — where ideas were earnestly discussed that seemed utterly impossible only a few years later. Such periods provide little windows into “what might have been,” alternative futures and possibilities that never happened, while also reminding us of the forces that bent things to the path they eventually went on.

Notes
  1. Manhattan District History, Book VIII, Los Alamos Project (Y) – Volume 3, Auxiliary Activities, Chapter 8, Operation Crossroads (n.d., ca. 1946). []