Posts Tagged ‘1940s’

Redactions

How to die at Los Alamos

Friday, February 13th, 2015

The people who ran the Manhattan Project worried about a lot of different things. Usually when we talk about this, it’s a story about the Germans, or the Japanese, or the physics, or other very specific things of that nature. But they also worried about banal things, like occupational safety: reducing the number of people injured, or killed, as part of doing their job.

Around half of the 500,000 or so people employed by the Manhattan Project were employed in construction. As a result, most of the injuries and fatalities associated with making the bomb were of a banal, construction-related variety. Heavy machinery, ditches, collapsing buildings — these were the most dangerous parts of the project for those who made it. Occasionally there were more exotic threats. Criticality accidents took the lives of two scientists in the immediate postwar, as is well known. Concerns about criticality excursions at the plants used to enrich uranium were a non-trivial concern. And there were other, more unusal ways to die, as you would expect from any body of people that large, working over so great an area, especially when they are concentrated in places that were for much of this period constant construction sites, as were Los Alamos, Oak Ridge, and Hanford.

Exhibit 14 - Fatalities at Los Alamos

“Exhibit 14: FATAL ACCIDENTS: Since the inception of the Project in the Spring of 1943, until September 1946, twenty-four (24) fatal accidents have occurred. The following history of these incidents was taken from hospital records, reports of investigation boards, and the safety division files.”

Some time ago I happened upon a list of all of the fatal accidents that occurred at Los Alamos between its inception in 1943 through September 1946. There were exactly twenty-four, an even two-dozen ways to die while working at an isolated nuclear weapons laboratory. I reprint them here, not only because there is a morbid fascination with this sort of thing, but because I’ve found that this list gives a really remarkable summary of the people of Los Alamos, the hazards of Los Alamos, and the work that goes into making a bomb, which requires much more than star physicists to pull off successfully. Each death was followed by an inquiry.

My summaries are below; the original document (linked to at the end of this post) contains more details on some of them. The copy of the document I have is very hard to read, so I may have gotten a few of the names wrong.

1943
  1. Estevan Roches, bulldozer operator. Crushed by a rock in his tractor while trying to build an access road to Los Alamos, at night. Died February 11, 1943.
  2. George H. Holtary, diesel motor mechanic. Was working on the power plant at Los Alamos, got crushed between a crankshaft and the housing. Died March 1, 1943.
  3. George J. Edwards, a soldier. Fell into a drainage ditch at night after drinking, injuring his back and puncturing his kidneys. Died July 19, 1943.
  4. Jose Montoya, construction laborer. Was digging an acid sewer ditch between “C” and “D” buildings. The 8-foot ditch was not reinforced and it collapsed on him. Died November 2, 1943. Investigation board recommended reinforcing ditches in the future.
  5. Pfc. Frederick Galbraith, military police. Was accidentally shot by another serviceman while sleeping. Another private was cleaning the gun and did not realize there was a live round in the chamber. It caused a severe wound in Galbraith’s thigh. He died of severe shock, November 4, 1943.
  6. Efren Lovato, construction laborer. Lovato was in the back of a dump truck being used to transport laborers to lunch. The truck’s accelerator got stuck and it crashed into a car at the pass gate and overturned, killing Lovato and another laborer, on November 20, 1943. Investigation board recommended increasing the size of the motor pool so the vehicles could be inspected more regularly.
  7. Fridon Virgil, construction laborer. Killed in the same accident as previous.
1944
  1. Fred Wolcott, contractor engaged to clear woods near the site. Attached a bulldozer to a tree and tried to pull it out. The tree snapped and fell on him. Witnesses say he appeared to be “frozen” to the seat of his tractor. Died May 9, 1944.
  2. Elmer R. Bowen, Jr., age 10 and a half. With a friend, was using a canoe from the former Los Alamos Ranch School in the main pond. His canoe capsized; neither him nor his friend could swim, and he drowned on July 1, 1944. He was the son of a maintenance mechanic, one who remained at Los Alamos for several decades after the war, until his retirement. Canoeing prohibited after death.
  3. Ernesto Freques, truck driver. He was standing next to a pile of reinforcing steel, unaware that workers on top were trying to move pieces and having difficulty because the steel was bent. The pile of steel collapsed on him; he was pinned against the truck, his heart lacerated. Died on July 6, 1944.
  4. Horace Russell, Jr., a research chemist, age 26. Fell from a horse while riding it in a canyon near the project. Suffered a serious head injury. Died August 5, 1944. The first of only four scientists on this list.
  5. Pfc. Hugo B. Kivsto, a member of the Provisional Engineer Detachment. Was fatally injured while driving an Army vehicle on a poorly graded surface of dirt road near Santa Cruz, New Mexico. Lost control of the vehicle while rounding a hazardous curve. Tried to jump clear of the truck as it went over the embankment and was pinned under it. Died on December 3, 1944.
 1945
  1. Pvt. Grover C. Atwell, member of Special Engineer Detachment. Assigned to hospital ward duty, died of an overdose of barbiturates taken from the hospital pharmacy. He died on July 21, 1945, but his body was not found until August 22, 1945. The report does not elaborate on why there was such a delay in finding his body. The investigation concluded he was “depressed over his assignment,” no indication of financial or family difficulties. Declared mentally irresponsible for his death, and thus his “death was in the line of duty and not a result of his own misconduct.”
  2. James W. Popplewell, civilian carpenter. Was working inside a building on August 7, 1945, at the same time a caterpillar tractor was pushing dirt over the roof. The roof collapsed and both tractor and dirt crushed Popplewell. Investigation blamed the foreman for not seeing if the building could support the load of the dirt and the tractor; the foreman was recommended for termination. This is a rare case of any liability being found.
  3. Harry Daghlian, physicist, age 24. Criticality accident with the so-called “demon core.” Report notes he “was exposed to too great radiation” on August 21, died on September 15, 1945. The report carries no further information on him and says that Health Physics is still investigating the matter. Second of the four scientists.
  4. Asa Houghton, civilian carpenter. Was going down the hill from project towards Santa Fe in his truck, front wheels locked and caused vehicle to run off the left side of the road, turned 5 or 6 times. Died of internal injuries on September 27, 1945.
1946
  1. Manuel Salazar, janitor. With three friends (also janitors), got extremely drunk on muscatel wine mixed with ethylene glycol (antifreeze). Died from ethylene glycol poisoning on January 29, 1945. Because deaths were not result of duty, descendants received no benefits of compensation.
  2. Alberto Roybal, janitor. Same event as above, same death date.
  3. Pedro Baca, janitor. Same event as above, same death date.
  4. Levi W. Cain, civilian blacksmith. Struck by car driven by a military sergeant on site. The sergeant was absolved of blame; the visibility was low, but car was not being driven at an excessive speed. Cain died on February 6, 1946.
  5. Louis Slotin, physicist, age 35. Criticality accident with the same core that killed Daghlian. While making measurements, “was exposed to radiation from radioactive materials” to a fatal degree. Third of the four scientists. Died on May 21, 1946. After Slotin’s death, criticality experiments were effectively put on hold until new safety guidelines could be devised.
  6. Livie R. Aguilar, truck driver for Zia Company. For reasons that were unknown (there were no witnesses or obvious evidence), his truck left the road and turned over into a trench, pinning Aguilard beneath it. He died on July 1, 1946.
  7. Joshua I. Schwartz, a scientist, age 21. With two other scientists (Robert A. Huffhines and William E. Bibbs), he was engaged in an experiment to trace air currents in Omega Canyon. They were instructed to use balloons or other non-flammable equipment for this. Instead, they tried to use smudge pots (smoke bombs). One of the smudge pots exploded, fatally injuring Schwartz, and critically injuring his companions (permanent blindness). Schwartz died on 2 August 1946. The investigation faulted their bosses with inadequate supervision. This resulted in at least one lawsuit over compensation. The fourth of four scientists.
  8. Herbert Schwaner, construction laborer. He was driving a bulldozer up a ramp when one of the treads locked, causing it to topple. He was pinned underneath. He was found five minutes later, by his brother, dead. He died on August 7, 1946.

It’s quite a list. Here is a copy of the original report, if you want more details on any of the above.1

Los Alamos population estimates, 1943-1946. For a more detailed breakdown of civilian duties, see this payroll census. The big dip in 1943 seems to be something about reshuffling how construction labor was accounted for when the University of California took over.

Los Alamos population estimates, 1943-1946. For a more detailed breakdown of civilian duties, see this payroll census. The big dip in 1943 seems to be something about reshuffling how construction labor was accounted for when the University of California took over.

Construction dominates, but automobiles, recreational mishaps, and scientific experiments make their appearance. As does suicide — one wonders what the report means by “depressed over his assignment” for the soldier at the hospital. The presence of a child reminds us that families lived at this secret laboratory — by the end of the war there were some 1,500 “dependents,” many of them children, living at the project site.

The Hispanic and/or Indian names point towards Los Alamos’ location. On the list of properties near the site that was seized by the Army (via condemnation), there are many Roybals, Montoyas, and Gomezes. In the list of Los Alamos badges, there are many Bacas, Virgils, Montoyas, and a Salazar.2  These are the people who lived there first, often written out of the more popular narratives of scientific triumph.

Even on the question of scientists, I was surprised to find two names I had not seen before: Russell and Schwartz. Both were young. Russell’s death adds a grim pall to all of that footage of scientists riding around in the woods on horses. Schwartz’s death is also a reminder of how much responsibility was thrust onto the young scientists — though frankly, it is maybe surprising that more people did not die this way, given the haste at which they worked and the toxicity, flammability, and radioactivity of the substances they were using.

Excerpt from a guide produced by the Oak Ridge Safety program.

Excerpt from a guide produced by the Oak Ridge Safety program.

Both Oak Ridge and Hanford had major industrial and public safety programs during the war. This was not just a matter of responsibility (though there was that), but also because industrial accidents caused lost-time problems. The more accidents, the slower it would be until they had an atomic bomb ready to use. At Oak Ridge and Hanford, they claimed an exceptional occupational safety record — their injury rates were (they claimed) 62% below those of private industry.

Sometimes it takes a raw document like this, something a little off the beaten path to get you out of the well-worn narratives of this history. One knows of the criticality accidents, because they are unusual, and they are famous. But who knew of the child drowning? The janitor’s night out gone wrong? The carpenter crushed by a bulldozer? The accidental shooting of a bunkmate? Out of these little details, grim as they are, a whole social ecosystem falls out. It doesn’t have to supplant the traditional scientific story, which is still an important one. But it augments it, and makes it more human.

Notes
  1. Exhibit 14, “Fatal Accidents,” (ca. late 1946) in Los Alamos Project Y, Book II: Army Organization, Administration, and Operation, copy in Manhattan Project: Official history and documents [microform] (Washington, DC: University Publications of America, 1977), reel 12. []
  2. Interestingly, I have found no badges in the list that obviously correspond to the people who died, with the exception of Elmer Bowen, Sr., the father of the little boy, and a few people who may be wives or relatives. There is a “Joe Montoya” but this seems like a common name. I wonder if this is because part of the procedure upon death would be to destroy their security passes? Obviously not everyone would have a security pass, but it is a little unusual to have exactly zero hits, including Daghlian, Slotin, Schwartz, and Russell, the scientists. []
Meditations

When bad history meets bad journalism

Wednesday, January 7th, 2015

A lot of people have been passing around the latest news story about the supposed “Nazi nuclear bunker” that was supposedly discovered in Austria. Normally I would not comment at length about such a thing, originating from tabloids and so obviously (to my eye) devoid of serious merit. But since the passing around has even made it to more austere publications (like the Washington Post) and because a number of people have asked me informally what I thought about it, I thought I could take it as an opportunity to talk about what bad history of the bomb looks like.

The Sunday Times (UK) version of the "bunker" story.

The Sunday Times (UK) version of the “bunker” story.

Cheryl Rofer has compiled some of the basics of the story on Nuclear Diner. The basics are this: an Austrian filmmaker named Andreas Sulzer has been trying to make a film about an Austrian bunker that dates from World War II. He has been claiming there was a nuclear connection to this bunker, and gotten some headline-grabbing tabloid stories about it, since 2013. What’s the evidence for it being a nuclear site? He claims that he has an American intelligence document from 1944 that lists it as a site of possible interest. He has made vague claims about radioactivity. It is part of an existing weapons production plant (a factory that produced rocket engines). Some physicists might have been sent there. Did we mention there was a bunker?

Yeah. That’s it. This stuff is pretty obviously thin, but let’s just say: Allied intelligence about German nuclear sites in 1944 was poor and scattered and means nothing. Radiation is everywhere and can fluctuate from a variety of natural and artificial sources — only by talking about levels of radiation do we start to wonder if something unusual is occurring, and only by talking about specific radioactive isotopes can we start to really wonder if any given radiation is of interest to us or not. (This is not hard to do — there are hand-held devices that can both measure radiation intensity and determine the isotopes in about 30 seconds, these days.1) The fact that it is part of an existing plant is probably evidence against it being a super-secret nuclear installation (compartmentalization). And physicists were involved in practically every technical program during World War II, so their presence tells us nothing one way or the other.

Forbes' version of the same story from February 2014.

Forbes’ version of the same story from February 2014.

The obvious thinness of this evidence, and the obvious motivation of the filmmaker — who has been denied a permit to dig around the site — should already be a sign to any self-respecting journalist that this is not worth touching. Certainly not without talking to some other experts about it. The only person anyone seems to have called up is Rainer Karlsch, whose own work on the German nuclear program is extremely controversial (Karlsch claims the Germans detonated some kind of dirty bomb or pure-fusion bomb — also on very thin evidence). For all of his outsized claims, at least Karlsch did his homework and tries to marshall evidence for his work. I don’t think Karlsch’s evidence fits the strength of his claims, and there are real technical problems with Karlsch’s reasoning, but there is at least a serious scholarly discussion to be had there. There is not one to be had (at least, not yet) about the Sulzer claims, because there is no there there. Karlsch’s only quoted comment is that he thinks the Germans got further along with their nuclear program than most people think (to be addressed below), and doesn’t comment on the Sulzer claims at all — which makes it not really a supporting comment for Sulzer at all.2

But if you slap “Nazi” and “nuclear” onto something, it gets a lot of hits, and that’s what appears to be the motivation here both for the Sunday Times and the many other sources that have picked up the same story and run it without checking in with anybody else to see whether it is even plausible. Which is a sad state of things.

December 2013 version of the story, from the Daily Mail (UK).

December 2013 version of the story, from the Daily Mail (UK).

There is a bunker. No credible evidence has actually been offered to make one think it has a nuclear connection. That the Germans had large underground bunkers for technical projects is well-known — that they had them for their nuclear program is not, because there is no evidence of this. (They did do some reactor work in some caves towards the end of the war, but it was small scale.) Newspapers should stop passing this kind of nonsense around… especially since it is not even “news” at this point — the bunker story has been circulating for over 2 years, without any additional increase in credibility!

About two or three times a year I get contacted by people who are working on things relating to the German or Japanese wartime nuclear programs. The appeal is obvious: there is a built-in audience for this kind of thing, and there are still areas of uncertainty with regards to these programs. I have written on here in the past on a few of the questions I’ve stumbled into with regards to the German program, for example. We don’t know everything about these programs, and there are reasons to think that there is still more to learn. So I’m always willing to engage with people on these questions.

At least the Washington Post hedged the headline a bit, "says he uncovered." Still misleading, but makes the factual basis a little more clear.

At least the Washington Post hedged the headline a bit, “says he uncovered.” Still misleading, but makes the factual basis a little more clear.

Some of the stuff strikes me as improbable or a little crack-pot-ish; some of it seems plausible and interesting. I’m a firm believer in the idea that sometimes non-academic historians stumble onto interesting things and interesting questions (John Coster-Mullen is a great example of this), and I don’t discriminate unless people show themselves to be going down truly untenable paths (like that small segment of the Internet who believes that all nuclear weapons are a hoax, which is just a truly silly “theory”).3 I will hear just about anyone out, and tell them what I find plausible or implausible about their ideas. I am a skeptical person — big claims need big evidence. But I do believe there is still a lot “out there” to be found on these topics, and maybe more than a few surprises yet.

The German nuclear program seems to attract a lot of “theorizing” in particular, ranging from the “they got further in it than most people think” (which is an easy argument to make since most people don’t know much about the German program at all) to the absurd extremes of “they made an atomic bomb and the only way the Americans got one themselves was by stealing it” (conspiracy country).

The 1945 version of the same headline — New York Herald Tribune, August 8, 1945, story about the Norsk Hydro plant, which also over-emphasized the closeness of Germany's getting the bomb for dramatic effect.

The 1945 version of the same headline — New York Herald Tribune, August 8, 1945, story about the Norsk Hydro plant, which also over-emphasized the closeness of Germany’s getting the bomb for dramatic effect. Click the image to read the article.

Public understanding of the German nuclear program is indeed a confused and often incorrect thing, owing to a history of the politicization of the topic. In the very early days after the dropping of the atomic bomb on Hiroshima, the “race with the Germans” narrative was played up very heavily by the Manhattan Project public relations people, both because it made for good drama and because it seemed to justify the US interest in the topic. And, indeed, the scientists who lobbied for the atomic bomb program between 1939 and 1944 or so did believe that the Germans might be ahead of them and that they were “racing” them to make the atomic bomb. It was not until late 1944 that the Alsos program reported back that the Germans had never gotten very far with their work, and that the US had never really been “racing” with them at all. Even today, though, we still see the legacy of this, with television programs and movies over-dramatizing the closeness of the “race,” and the importance of things like the sabotage of the Norsk Hydro facility, all of which makes it look like the Germans were very close indeed.

On the other side of the coin, we also have things like the Copenhagen play, which is an excellent piece of drama (and I am indeed a fan) but has infected a new generation with the idea that the Germans made no progress at all with regards to nuclear weapons — and indeed, had never even seriously considered the matter — because Heisenberg had consciously sabotaged the whole project. Never mind that Heisenberg’s own claims were far more nuanced on this point (he was always vague on this, only implying in a round-about way that they might not have made a bomb because they didn’t really want one). The play and the press around it has led a lot of people to think that the Germans knew really nothing about nuclear weapons development, and that they had intentionally avoided making them.4

Allied troops disassembling the German experimental research reactor at Haigerloch, as part of the Alsos mission.

Allied troops disassembling the German experimental research reactor at Haigerloch, as part of the Alsos mission.

The truth, so far as we know it now, is somewhere other than these two extremes. Mark Walker’s two books (German National Socialism and the Quest for Nuclear Power, 1939-1949 and Nazi Science: Myth, Truth, And The German Atomic Bomb) are still excellent, though a bit more has come out since then. The basic gist of Walker’s work is that the German program knew a lot on paper, but never quite crystallized everything organizationally or technically to keep their program from being anything more than a side-project, focused primarily on reactor development. They never developed large-scale isotopic enrichment facilities, and they never got a reactor that went critical. Their reactor work was sophisticated given the conditions under which it was being done, but it never achieved criticality. Some members of the various teams that worked on the project had some fairly accurate understandings of how a nuclear weapon might be made, but there was also a lot of confusion circulating around (some members of the team understood it would be a fast-neutron fission reaction in enriched material, some were confused and focused on it being basically an out-of-control pile). Some were considering rather advanced designs (Karlsch has convinced me that they thought a bit about implosion, for example), but the whole thing was mostly a exploratory program.

The plausibility of any new arguments about German successes with their nuclear programs is always limited in part by what we know about the technical requirements of such an endeavor. The Manhattan Project need not be the only model of a successful nuclear program (it was in many ways unusual), but it does provide some baseline metrics for talking about nuclear programs of the 1940s. Any successful plutonium-breeding program is going to require fairly large reactors, because plutonium reprocessing extracts only grams of “product” from each ton of uranium fuel that goes into it. (Each of the three early Hanford reactors extracted only 225 grams of plutonium from every ton of uranium processed.) Any successful isotopic-enrichment program is going to require huge feed supplies of uranium (the Manhattan Project approaches consumed thousands of tons of uranium), pretty large facilities, and a lot of electricity.

When Alsos leader Sam Goudsmit was investigating the Germany nuclear work, he was struck by how little of it was kept very secret — evidence, in his mind, that they had not gotten very far with it. (S.A. Goudsmit and F.A.C. Wardenburg, "TA-Straussburg Mission," (8 December 1944), copy in the Bush-Conant file, Roll 1, Target 6, Folder 5.)

When Alsos leader Sam Goudsmit was investigating the Germany nuclear work, he was struck by how little of it was kept very secret — evidence, in his mind, that they had not gotten very far with it. (S.A. Goudsmit and F.A.C. Wardenburg, “TA-Straussburg Mission,” (8 December 1944), copy in the Bush-Conant file, Roll 1, Target 6, Folder 5.)

Separate from the technical argument is a bureaucratic one — if the Germans supposedly made such progress, why is was there no organizational evidence of it in the copious reports, papers, formal and informal statements, and so on that were discovered by the Alsos project, later researchers, and at Farm Hall? Big programs leave big traces. If one wants to claim that the German program was big, one has to show where those traces are, or come up for a plausible argument for why there are no traces.

This does not mean that one might not find more evidence in the future. It just means that any claims and evidence need to fit within the existing technical and bureaucratic narratives. For example, one could argue, “oh, but they did have a massive isotopic enrichment plant, and it was here, and here is evidence of — if one had the evidence. On the bureaucratic side, one could argue that people who we previously thought were important in the program (e.g. Gerlach) were actually out of the loop entirely. Or something along those lines.

Weekly World News, 2002: "Confederacy was Building an Atomic bomb."

Weekly World News, 2002: “Confederacy was Building an Atomic bomb.” No comment!

But you can’t just find a hole in the ground and say, “ah, here is where Hitler was making a bomb.” Aside from the implausibility of a nuclear program existing in a single underground bunker, by itself this kind of claim hasn’t done the work to be plausible. At best, if done in good faith, it is a claim along the lines of “oh, maybe this is worth looking into more.” That is fine — hey, I’d even nominally support that — but one shouldn’t be going to the newspapers about it at that stage, and the newspapers shouldn’t be passing off your claim as having more validity than half of the other implausible claims that circulate around these topics. This is premature, and the net effect is going to be misleading for the readership.

As historians, we need to be open to the idea that there are still mysteries to be solved, secrets to be unearthed, even about ground that superficially looks well-trodden. But I wish journalists would do a little better than just re-printing the overblown claims of unreliable sources, without checking with experts on their plausibility. Couching it as, “this guy made a claim” doesn’t get you off the hook, because we all know that only the initial, big-claim story is the one that will be passed around, and that almost nobody will notice when no follow-ups occur, or the mild “so no evidence turned up for this guy’s big claim” story comes out.

Journalists — You can do better!

Notes
  1. I got to see a demonstration of the lanthanum bromide detectors that U.S. Customs and Border Protection uses at Port Newark a few weeks back — they were pretty neat. Totally hand-held, hold it up to something interesting and click a button and 30 seconds later it tells you what isotope it is, color-coded by whether it is natural in origin, a medical isotope, or something with nuclear weapons relevance. []
  2. Karlsch’s work deserves to be gone over more carefully. Its lack of translation into English has probably inhibited this to some degree. Karlsch has found some interesting documents, but I am not sure they add up to what he claims they do. For example, Karlsch and and Mark Walker published an article in 2005 where they claimed they had a diagram of a Nazi atomic bomb — it is clearly not one. For one thing, it has “plutonium” (the American term for Element 94) labeled on it, which clearly dates it as a postwar creation. And for another thing, it is probably a crib from Hans Thirring’s 1946 Die Geschichte der Atombombe, which itself is explicitly based on the Smyth Report. Karlsch’s work is filled with a muddled discussion of pure-fusion concepts (which wouldn’t work), dirty bombs, atomic bombs of various sorts, “mini-nukes,” and all sorts of other indications of a less-than-complete understanding. []
  3. For those who are curious: The “all nukes are a hoax” theory seems to stem from a couple different sources. The technical argument is that fast neutron chain reactions are impossible, because the fission cross-section of U-235 is small for fast neutrons. The cross-section is indeed small for high-energy neutrons, which is why reactors use a moderator to slow the neutrons down and increase the likelihood of their capture by the small amounts of U-235 in the nuclear fuel. What is weird is that the people making this argument don’t seem to realize that this is exactly why you use 80-90% enriched material in a bomb — it is to overcome this low probability of fissioning by just putting a ridiculous number of targets in the area. It is also why there are tampers, neutron reflectors, and the like, and also why even a relatively sophisticated weapon like the Fat Man only fissioned something like 13-18% of its fissile material, and the Little Boy bomb only fissioned around 1% of its fissile material. They also have weirdly interpreted the “Hiroshima and Nagasaki are not that different from the firebombing of Tokyo” argument (to a rather absurd conclusion, that it was just a firebombing, despite the fact that firebombing and atomic bombing have really different outcomes), believe that the photographs of the mushroom clouds are all faked (despite the fact that such a level of fakery was really quite beyond the technology of the 1940s — similar to the “Apollo moon hoax,” it would have been easier to make an atomic bomb in the 1940s than to fake an atomic bomb convincingly on film, at least to the degree of documentation that we have on them from the time), and believe that every scientist in the entire world (except for the random engineer who came up with this dumb theory) is in on the secret and has reasons to propagate it indefinitely (and I am apparently in on the hoax as well, to my surprise). The one person I e-mailed with about this, just trying to see what the limits of their rationality were and what it spawned from, eventually let on that to him, one of the most convincing pieces of evidence for this theory is the number of Jews who were involved in the creation of the bomb, wink wink, nudge nudge. This probably hits at the real origin of this bad idea — just another form of mis-matched anti-Semitism grafting itself onto another source. That my last name is a Jewish-sounding one did not apparently resonate with the person e-mailing me. []
  4. On the backs-and-forths of the Heisenberg story, see esp. Mark Walker, German National Socialism and the Quest for Nuclear Power, 1939-1949 (Cambridge: Cambridge University Press, 1989), 204-221, and the essays in Matthias Dörries, Michael Frayn’s “Copenhagen” in Debate: Historical Essays and Documents on the 1941 Meeting Between Niels Bohr and Werner Heisenberg (Berkeley, CA: Office for History of Science and Technology, UC Berkeley, 2005). []
Visions

The button that isn’t

Monday, December 15th, 2014

One of my favorite articles from The Onion concerns the imagined allure of “the button”:

"Obama Makes It Through Another Day Of Resisting Urge To Launch All U.S. Nuclear Weapons At Once" - The Onion

Despite being constantly tempted by the seductive power of having an apocalyptic arsenal at his fingertips, President Barack Obama somehow made it through another day Tuesday without unlocking the box on his desk that houses “the button” and launching all 5,113 U.S. nuclear warheads. …

Though the president confirmed his schedule was packed with security briefings, public appearances, and cabinet meetings, he said he couldn’t help but steal a few glances at the bright red button, which is “right there, staring at [him], all the time.”

The article manages to wring a lot of humor out of the idea that on the President’s desk is a big red button that starts World War III.

Like much of The Onion’s satire, it is exceedingly clever in taking a common trope and pushing it into absurd territory. Even the physicality of the idea of a “button” is toyed with:

“Did you know that if you sort of put enough weight on the button with your fingertip, you can feel a little slack there before it actually clicks?” Obama added. “Thank you, and God bless America.”

I was thinking about this article a few months ago because I was asked by my friend from grad school, Latif Nasser, if I would be interested in talking to him and NPR’s Robert Krulwich about “the button” for a Radiolab episode they were working on. The Radiolab show was initially meant to be about buttons — in all senses of the term — but they kept finding that things that they thought were buttons were in fact either non-buttons or non-functional buttons. You can listen to the full episode here: “Buttons Not Buttons.”

You should listen to the whole episode, but — spoiler alert — the interesting thing about the nuclear “button” is that there isn’t a nuclear button. That is, nuclear war can’t be started by just pounding a big red button. Sorry. Waging a nuclear war requires a lot more activity, spread out across a vast geographical area, and is a complex interaction of technical, organizational, and political issues. In the Radiolab interview, I attempted to paint in broad strokes the kind of vast technical and organizational networks that are needed to maintain the United States’ command and control systems — the systems that let you use nukes when you want to, and make sure that nukes don’t get used when they are not supposed to be used.

The problem with a big red button is that someone might actually press it. Like a cat. Source: Ren and Stimpy, Space Madness.

The problem with a big red button is that someone might actually press it. Like a cat. Source: Ren and Stimpy, Space Madness.

The Onion article indicates, in its wry way, one of the key reasons there isn’t a single “button” — it would be way, way too dangerous. Nobody wants nuclear war to be that easy to start. Or, as I like to put it, you don’t want a nuclear weapon that can be set off by a cat. Because you know that, sooner or later, a cat would set it off. Such is the way of cats. There are places in the world where big red buttons exist. But they are usually used to stop activity, not start it. They are emergency shutoff switches, things that you need to push in a big hurry, without too much hassle. And even they might require you to break some glass first.

On the other hand, if you’re a believer in deterrence and all that, you don’t want it to be too hard to start nuclear war. So this is just another variation of the “always/never” problem: you want to be able to start nuclear war if you need to, and start it quickly and effectively, but on the other hand, you want to never start nuclear war accidentally.

"Nuclear C3 [Command, Control, Communication] Transport Systems" — an attempt to characterize the technical, organizational, and political systems needed to actually start nuclear war in the United States today. Source: The Nuclear Matters Handbook, by the Office of the Assistant  Secretary of Defense for Nuclear, Chemical, and Biological Defense Programs.

“Nuclear C3 [Command, Control, Communication] Transport Systems” — an attempt to characterize the technical, organizational, and political systems needed to actually start nuclear war in the United States today. Source: The Nuclear Matters Handbook, by the Office of the Assistant Secretary of Defense for Nuclear, Chemical, and Biological Defense Programs.

From a technical standpoint, this means that you have to engineer a pretty complex system. In principle, the United States President has complete control over whether nuclear war starts. But the President doesn’t work in a missile silo. So somewhere between the President and the silo has to be a delegation of authority, and a subsequent potential loss of control. One could, in theory, completely automate that control — you could install a single “button” — but aside from the technical difficulty of that, there are a lot of new potential errors that get introduced.

Eric Schlosser’s Command and Control is a great read if you are interested in how this problem gets addressed over the course of the Cold War. Michael Gordin’s Five Days in August is, in part, a great description of how these issues were wrangled with even in the earliest days of nuclear weapons as political control transferred from Potsdam to Washington and Tinian. If I could add footnotes to radio interviews, I would prominently name-check both of these books — they greatly improved my own understanding of this. As did the work of my friend Dan Volmar, who is writing a dissertation on US command and control systems. And I need to give a massive hat-tip to Stephen Schwartz, who clued me into the Roger Fisher “cut the heart out” that I wrote about a few years back.

A submarine-launched ballistic missile trigger. Courtesy of Stephen Schwartz.

A submarine-launched ballistic missile trigger. Photo by the always amazing Paul Shambroom; courtesy of Stephen Schwartz.

Of course, there sometimes are switches, keys, and — yes — buttons, as part of the overall launching systems. But they aren’t centralized, and they are always more complicated than a simple big, red button. US ICBM launches require two simultaneous keys to be turned by two different people, on different sides of the room, the idea being that the odds of two people deciding to collude on an illegal launch are lower than one. SLBM launches, Stephen Schwartz reports, require the use of a pistol-grip “trigger” that is kept in a safe— a button, of sorts, though one that is hard to accidentally set off.

OK, so there isn’t a single nuclear button. Why do we talk about a button? This is a great history of technology question — “the button” is a metaphor, and not a new one. Starting in the 19th century, “the button” (or the “push button” or other variations on the same thing) started becoming a standard English idiom for “quick and easy and automatic.” The idea that you “push a button” and something happens — as easy as that! — shows up in the late Machine Age and continues onward.

So “the button” is just a metaphor for how technology makes things easy. That’s why everything in The Jetsons is button-based — the future was meant to take this to the extreme, where George Jetson would just spend all day at work pressing a single button. (Of course, many of us do press buttons all day — I am pressing quite a few as I type this — but generally not just one button.) If you combine the button imagery with the atomic bomb, it becomes a comment on the way technology has made mass destruction easy.

"Now I am become Edison, Wrecker of Worlds": fictional account of Edison destroying England using "button no. 4," 1896. Source: The Electrical Trade, August 1, 1896.

“Now I am become Edison, Wrecker of Worlds”: fictional account of Edison destroying Great Britain using “button no. 4,” 1896. Source: The Electrical Trade, August 1, 1896, page 9.

In fact, the idea that technology had made it so easy to destroy the world that a single button could set it all off predates nuclear fission. In the 1890s, a Parisian newspaper published a skit about Thomas Edison destroying all of England by joining some wires and pushing “button No. 4.” For this anecdote, and several others relating to “pushbutton” world destruction prior to fission, I am grateful to Spencer Weart’s Nuclear Fear: A History of Images.1

There are other “button” stories I found while searching from newspaper and journal databases. In 1929, the famous American physicist Robert Millikan was quoted as saying that “no ‘scientific bad boy’ ever would be able to blow up the world by releasing atomic energy,” (!), and he later “scoffed at the idea that in the future by pressing a button a man might have an army of atomic servants wash his face, mend his clothing or make his bed.” In a 1932 review of the 1928 proto-atomic-bomb drama “Wings Over Europe,” it is noted that “All the scenes are set in Downing-street and the chief character is a young scientist who has presented to the cabinet a secret that could destroy the world by pressing a button.” In article from the Weekly Irish Times in 1932, it is feared that atomic energy will enable “a time when, by the pressing of a button or turning of a switch, it will be possible for somebody to explode the whole world like a penny balloon. It will be a tremendously lethal opportunity.” On these proto-atomic bomb fantasies, especially in the U.K. context, I found Graham Farmelo’s Churchill’s Bomb very useful. Churchill himself was an atomic-bomb speculator in the H.G. Wells vein, writing about atomic energy as early as 1931.

August 20, 1945: a LIFE magazine correspondent reports on "push-button" battles of the future.

August 20, 1945: a LIFE magazine correspondent reports on “push-button” battles of the future.

So when the actual atomic bomb came along, there was already a ready-made imagery to be applied to it. (And Weart’s book is excellent at demonstrating this well beyond the realm of buttons, too.) So when did people first start applying the button metaphor to the bomb? As early as late August 1945, there are discussions of “push-button” battles. By November 1945, when the physicist Edward Condon argued during Congressional testimony that “The next war should be described as the War of the Pushbuttons,” it was already something of a cliché. The idea of World War III being a “pushbutton war” started pretty early.

I have to admit, I was a little uncertain how the “button” line of discussion was going to come together when I was first contacted by Latif, but the more I thought about it, the more I thought it was a nice way to get into a lot of different, interesting issues both about the history of the bomb (and what “the button” means, metaphorically), but also in explaining why there isn’t a button, it allows for a nice, tangible, interesting way to bring up the questions involved in command and control systems — moving the discussion of the bomb out of the realm of pure imagery and into the tangible and real.

Notes
  1. The specific Edison piece, with “button No. 4,” comes from a source Weart cites: Wyn Wachhorst, Thomas Alva Edison: An American Myth (MIT Press, 1981), 103. A copy of the actual story is reproduced above, via Google Books (and thanks to Latif for finding that copy of it). []
Redactions

The Fat Man’s uranium

Monday, November 10th, 2014

What a long set of weeks it has been! On top of my usual teaching load (a few hours of lecture per week, grading, etc.), I have given two public talks and then flown to Chicago and back for the annual History of Science Society meeting. So I’ve gotten behind on the blog posting, though I have more content than usual for the next few weeks built up in my drafts folder, without time for me to finish it up. During this busy time, by complete coincidence, I also got briefly interviewed for both The Atlantic (on plutonium and nuclear waste) and The New York Times (on the apparent virality of nuclear weapons history).

Louis Slotin and Herb Lehr at the assembly of the Trinity "Gadget." Source: Los Alamos National Laboratory Archives, photo TR-229.

Louis Slotin and Herb Lehr at the assembly of the Trinity “Gadget.” Source: Los Alamos National Laboratory Archives, photo TR-229.

The Times article had a phrase in it that has generated a few e-mails to me from a confused reader, so I thought it was worth clarifying on here, because it is actually an interesting detail. It is one of those funny phrases that if you knew nothing about the bomb you’d never notice it, and if you knew a good deal about the bomb you’d think it was wrong, but if you know a whole lot more than most people care to know unless they are serious bomb nerds you actually see that it is correct.

Here’s the quote:

First, he glanced at the scientists assembling what they called “the gadget,” a spherical test device five feet in diameter. Then, atop a wooden crate nearby, he noticed a small, blocky object, nondescript except for the role he suddenly realized it played: It was a uranium slug that held the bomb’s fuel. In July 1945, its detonation lit up the New Mexican desert and sent out shock waves that begot a new era.

I’ve added emphasis to the part that may seem confusing. The Trinity “Gadget” and the Fat Man bomb, as everyone knows, were fueled by fission reactions in a sphere of plutonium. The Little Boy bomb dropped on Hiroshima, by contrast, was fueled by enriched uranium. So what’s this reference to a uranium slug inside the Trinity Gadget? Isn’t that wrong?

Detail from the above photo showing the tamper plug cylinder. Inset is a rare glimpse of what the tamper probably looked like, taken from a different Los Alamos photo related to Slotin's criticality accident. (It is in the middle-right of the linked photo. Yes, I cop to spending time searching the edges of photos like this for interesting things...) You can see how the tamper plug, rotated, would be inserted into the middle of the tamper sphere.

Detail from the above photo showing the tamper plug cylinder. Inset is a rare glimpse of what the tamper probably looked like, taken from a different Los Alamos photo related to Slotin’s criticality accident. (It is in the middle-right of the linked photo. Yes, I cop to spending time searching the edges of photos like this…) You can see how the tamper plug, rotated, would be inserted into the middle of the tamper sphere.

Perhaps surprisingly — no, it’s not. There was uranium inside both the “Gadget” and Fat Man devices — in the tamper. The tamper was a sphere of uranium that encased the plutonium pit, which itself encased a polonium-beryllium neutron source, Russian-doll style. Here uranium was chosen primarily for its physical rather than its nuclear properties: it was naturalunenriched uranium (“Tuballoy,” in the security jargon of the time), and its purpose was to hold together the core while the core did its best to try and explode. (It also helped reflect neutrons back into the core, which also worked to improve the efficiency.)

The inside of an exploding fission bomb can be considered as a race between two different processes. One is the fission reaction itself, which, as it progresses, rapidly heats the core. This heating of the core, however, causes the core to rapidly expand — the core is trying to blow itself apart. If the core expands beyond a certain radius, the fission chain reaction stops, because the fission neutrons won’t find further plutonium nuclei to react with. If you are a bomb designer, and want your bomb to have a pretty big boom, you want to hold the bomb core together as long as possible, because every 10 nanoseconds or so you can hold it together equals another generation of fission reactions, and each generation releases exponentially more energy than the previous.1

An image that somewhat evokes how bomb designers talk about the dueling conditions inside of the bomb, when they are talking to each other. The "snowplow region" is where the expanding bomb core runs into the tamper and is compressing it from the inside. This is a level of bomb design that I would have normally assumed would be classified but it has been very clearly declassified here, so I guess not. From Glasstone, "Weapons Activities of Los Alamos, Part I" (see footnotes).

An image that somewhat evokes how bomb designers talk about the dueling conditions inside of the bomb, when they are talking to each other. The “snowplow region” is where the expanding bomb core runs into the tamper and is compressing it from the inside. This is a level of bomb design that I would have normally assumed would be classified but it has been very clearly declassified here, so I guess not. From Glasstone, “Weapons Activities of Los Alamos, Part I” (see footnotes).

So in the Fat Man and Trinity bombs, this is accomplished with a heavy sphere of natural uranium metal. Uranium is heavy and dense, and the process of making plutonium and enriched uranium required the United States to stockpile thousands of tons of it, so the relatively small amount needed for a tamper was easily at-hand. It makes a good substance with which to try and hold an exploding atomic bomb together. The Little Boy bomb, as an aside, used a tungsten tamper, for some reason (maybe to avoid excessive background neutrons, I don’t know).

Now to add one more little bit of detail: we tend to think of the Trinity/Fat Man implosion bombs as just being a set of spheres-inside-spheres. This is a convenient simplification of the actual geometry, which had other factors that influenced it. The tamper, for example, was not just two halves of a hollow sphere that could fit together. Rather, it was more like a solid sphere out of which a central cylinder had been removed. The cylinder was known as the “tamper plug,” and was itself made of two halves that, when assembled, had room for the plutonium pit inside of them.

Why do it this way? Because the scientists and engineers wanted to be able to insert the fissile pit portion into the bomb as one of the final additions. This makes good sense from a safety point of view — they wanted it to be relatively easy to add the final, “nuclear” component of the bomb and to keep it separate from the non-nuclear components (like the high explosives) as long as possible. I don’t want to over-emphasize the “ease” of this operation, because it was not a quick, last-minute action to put the pit inside the bomb. (Some later bomb designs which featured in-flight core insertion were designed to be just this, but this was some years away.) It was still a tetchy, careful operation. But they could assemble the entire rest of the tamper, pusher, and high explosives, then remove one layer of high explosives, remove the top of the pusher, and then lower the tamper plug (with pit) into the center, then replace all of the other parts, hook up the detonators and electrical system, and so on.

A rendering I made in Blender to illustrate the principle here. The pit and initiator are inside of the plug (expanded at right), which is then sealed into a cylinder and inserted into the tamper sphere at the center of the bomb. The tamper is itself embedded in a boron shell which is inside of an aluminum shell which is inside of the explosive lenses which is inside of the casing. This is part of a modeling/visualizing project I've been working on for a little while now and will post more on at a future date. 

A rendering I made in Blender to illustrate the principle here. The pit and initiator are inside of the plug (expanded at right), which is then sealed into a cylinder and inserted into the tamper sphere at the center of the bomb. The tamper is itself embedded in a boron shell which is inside of an aluminum shell which is inside of the explosive lenses which is inside of the casing. This is part of a modeling/visualizing project I’ve been working on for a little while now and will post more on at a future date. The dimensions are roughly correct though there are still many simplified detail (e.g. exactly how the plug fits together — there were uranium screws!).

So when John Coster-Mullen describes, as in the previously-quoted New York Times article, finding a picture of the tamper plug, it’s kind of a cool thing. There’s only one picture that shows it (the one at the beginning of this post), and it is one of those things that you don’t even usually notice about that picture until someone points it out to you. I never noticed it until John pointed it out for me, even though I’d seen the picture many times before. Usually one’s attention is drawn to the Gadget sphere itself, and the people standing around (including Louis Slotin, who would later be killed by playing with a core). It’s kind of surprising it was declassified, since the length of the tamper plug is the diameter of the tamper, and the width of the plug is just a little bigger than the diameter of the plutonium core. The US government usually doesn’t like to reveal, even inadvertently, those kinds of numbers.

There is also one little fact about the natural uranium in the Gadget and Fat Man bomb that is not well appreciated, and I didn’t appreciate well until reading John’s book. (Which I have heard people say is rather expensive for a self-published production, but if you’re a serious Manhattan Project geek it is hard to imagine how you’d get by without a copy of it — it is dense with technical details and anecdotes. It is one of the only books that I don’t often bother to put back in the bookcase because I end up needing to reference it every week or so.)

Neutron cross-sections for the fissioning of uranium and plutonium. The higher the cross-section, the more likely that fission will occur. (Not shown on here is the competing capture cross-section, which matters a lot for U-238.) The indicated "fission neutron energy" means that that is the approximate energy level of neutrons released from fission reactions. So you can see why, in a reactor, those are slowed down by the moderator to increase the likelihood of fissioning. In a bomb, there is no time for slowing things down, so you need much more fissile material in much higher concentrations. Source: World Nuclear  Association.

Neutron cross-sections for the fissioning of uranium and plutonium. The higher the cross-section, the more likely that fission will occur. The indicated “fission neutron energy” means that that is the approximate energy level of neutrons released from fission reactions. So you can see why, in a reactor, those are slowed down by the moderator to increase the likelihood of fissioning. In a bomb, there is no time for slowing things down, so you need fissile material in much higher concentrations. Source: World Nuclear Association.

In talking about which elements are fissile — that is, can sustain a nuclear fission chain reaction — technical people tend to talk about neutron cross sections. This just means, in essence, that the likelihood of a giving elemental isotope (e.g. uranium-235, plutonium-239) undergoing fission when encountering a neutron is related to the energy of that neutron. At the size of neutrons, energy, speed, and temperature all considered to be the same thing. If you look at a neutron cross section chart, like the one above, you will see that uranium-235 has a high likelihood of fissioning from slow neutrons, and a low-but-not-zero likelihood of fissioning from faster neutrons. You will also see that the neutrons released by fission reactions are pretty fast. This is why to sustain a chain reaction in uranium you either need to slow the neutrons down (like in a nuclear reactor, which uses a moderator to do this), or pack in so many U-235 atoms that even the low probability of fissioning from fast neutrons doesn’t mean that a chain reaction won’t happen (like in a nuclear bomb, where you enrich the uranium to be mostly U-235).

Still with me? If you look a little further on the graph, you’ll see that uranium-238 also has a possibility of fissioning, but it is a pretty low one and only even becomes possible with pretty fast neutrons. This is why, in a nutshell, that unenriched uranium can’t power an atomic bomb by itself: it is fissionable but not fissile, because it can’t reliably take fission neutrons and turn them into further fission reactions. But people who have studied how thermonuclear weapons are used know that even uranium-238 can contribute a lot of explosive energy, if it is in the presence of a lot of high-energy neutrons. In a multistage hydrogen bomb, at least 50% of the final explosive energy is derived from the fissioning of U-238, which is made possible by the high-energy neutrons produced from the nuclear fusion stage of the bomb (which itself is set off by an initial fission stage). The neutrons produced by deuterium-tritium fusion are around 14 times more energetic than fission neutrons, so that lets them fission U-238 easily. From the cross-section chart above, you can see that U-238 fissioning can happen from fission neutrons, but only if they happen to be pretty high energy to begin with and stay that way. In practice, neutrons lose energy rather quickly. Still, according to a rather sophisticated analysis of the glassified remains of the Trinity test (“Trinitite”) done a few years back by the scientistsThomas M. Semkow, Pravin P. Parekh, and Douglas K. Haines, a significant portion of the final fissioning output at Trinity (and presumably also Nagasaki) came from the fast fissioning of the tamper, with some of that energy released from the U-238 fissioning.2

For the hardcore bomb geeks, here is a sort of "conclusion table" from the Semkow et al. article. Note that they calculate at least 30% fissioning from uranium, and give some indication the amount of compression of the core, the number of neutrons created, and so on.

For the hardcore bomb geeks, here is a sort of “conclusion table” from the Semkow et al. article. Note that they calculate at least 30% fissioning from uranium, and give some indication the amount of compression of the core, the number of neutrons created, and so on. Their terminology of the “eyeball” is taken from Richard Rhodes, who uses the term in passing in The Making of the Atomic Bomb, and refers to the confined area where the fission chain reaction is taking place.

How significant? Semkow et al. calculate that about 30% of the total yield of the Trinity test came from fissioning of the uranium tamper, which translates to about 6 kilotons of energy. If they had made the tamper out of tungsten (as was the Little Boy tamper), then the total yield of the Gadget would have only been around 14-15 kilotons — not that different from Little Boy (which was ~13-15 kt). And presumably if the Little Boy bomb had used a uranium tamper, assuming that didn’t cause problems with the design (which it probably would have, otherwise they probably would have used one), it would have had the same yield. (This doesn’t mean that Little Boy wasn’t, in fact, horribly inefficient — it got about the same yield but it required 10X the fissile the material to do so!) The total mass of the tamper was around 120 kg of natural uranium, so if it contributed 6 kilotons of yield that means around 350 grams of the tamper underwent fission, and that is about 0.3% of the total mass.3

So the fact that Trinity and Fat Man had uranium inside of them is already kind of interesting, but the fact that a large portion of the blast derived from that uranium is sort of a neat detail. Why don’t we generally learn about this? It isn’t that it is so terribly classified, per se, but it does require a lot of detailed explanation, as evidenced by the length of this post. We tend to abstract the mechanics of the bombs for explaining their conceptual role, and explaining the basic concepts of how they work. I have no problem with this, personally, because hey, let’s be honest, the exact amount of energy derived from different types of fissioning in the bombs is a pretty wonky thing to care about! But every once in awhile you need to understand the wonky things if you want to talk about, say, what that funny little “plug” is in the top-most photograph, and its role in the bomb. I suppose one of the points of the phenomena described by the Times article, where the geek population on the Internet is providing a newfound audience to Manhattan Project details, is that these sorts of wonky aspects are no longer limited to people like John Coster-Mullen, Carey Sublette, or myself. There are some people who might see this focusing on the technical details as missing the broader picture. I don’t happen to think that myself — much of the broader picture is in fact embedded in the technical details, and “new” discussions of technical details are one way of shaking people out of the calcified narratives of the Manhattan Project, something which, as we approach the 70th anniversary of Hiroshima and Nagasaki, seems to me a valuable endeavor.

Notes
  1. Calculating the efficiency of the bomb as a function of how well you can hold it together is apparently the essence of the still mostly-classified Bethe-Feynman formula. It is described qualitatively in Samuel Glasstone, “Weapons Activities of Los Alamos Scientific Laboratory, Part I,” LA-1632 (January 1954), 34-37. My copy of this report comes from the NNSA’s FOIA Reading Room. I downloaded the file in 2009, and sometime since then all of their PDFs have gotten corrupted somehow, and so many of the pages of the PDFs now available on their site are unreadable. For those who are curious, at a technical level, the corruption involved a systematic stripping out of the carriage return (0D) ASCII characters from the PDFs — there are none in any of the files, and there should be several thousand of them. Here is a screenshot from a hex editor showing the corrupted file (on left) versus the uncorrupted one (on the right). There seems to be no easy fix for this problem. I have tried to contact the NNSA about this but have gotten no response. It is one of many troubling incidents revealing, in my view, the very low priority that public release of information, and poor understanding of public-facing information technology, with regards to the present nuclear agencies. []
  2. Thomas M. Semkow, Pravin P. Parekh, and Douglas K. Haines, “Modeling the Effects of the Trinity Test,” Applied Modeling and Computations in Nuclear Science, ACS Symposium Series (American Chemical Society: Washington, DC, 2006), 142-159. The authors do not estimate the amount of tamper energy to have been released from U-238 fissioning as opposed to U-235 fissioning. []
  3. A 120 kg tamper of natural uranium ought to contain around 840 grams of U-235 in it, as an aside, which if that all fissioned at once would release around 14 kilotons of energy. The rule of thumb for uranium is that every kilogram which fissions releases about 17 kilotons. []
Meditations

Tokyo vs. Hiroshima

Monday, September 22nd, 2014

How many people would have died if an atomic bomb had been dropped on Tokyo in early 1945, instead of firebombs? Before you accuse me of excessive obsession with morbidity (as one anonymous e-mailer recently did), let me explain to you how I came to ask myself this question, and what the consequences of the answer are.

Before the dropping of the atomic bomb on Hiroshima and Nagasaki, there was the burning of Tokyo. Operation Meetinghouse, the early March 1945 raid on Tokyo that involved over 330 B-29s dropping incendiary bombs from low-altitude at night, killed roughly 100,000 people, and may have injured and made homeless an order of magnitude more. As with all statistics on the damage caused by strategic bombing during World War II, there are debatable points and methodologies, but most people accept that the bombing of Tokyo probably had at least as many deaths as the Hiroshima bombing raid, and probably more. It is sometimes listed as the most single deadly air raid of all time as a consequence.

The ruins of 1945: Tokyo, left, and Hiroshima, right.

The ruins of 1945: Tokyo, left, and Hiroshima, right.

So it is understandable that many people, including myself, point to Tokyo whenever people want to talk about Hiroshima and Nagasaki. You can’t see the atomic bombings in isolation. The practice of targeting civilian areas with massively destructive aerial bombing had already been done before. And to some, the atomic bombs were just a refinement of the art of area bombing — a more efficient means to accomplish the same ends.1

However, there are a few points that I fear get missed in that kind of equivalence. I certainly agree that the philosophy of bombing used at Hiroshima and Nagasaki wasn’t a new one. Indeed, the experience of firebombing gave a lot of guidance to the question of nuclear targeting. The goals were similar, though the people planning the atomic bombs emphasized the raw terror that they hoped such a spectacle would inspire.

But I depart from the standard comparison in two places. The first is the idea that since the atomic bombings were not original in targeting civilians, then they do not present a moral or ethical question. As I’ve written about before, I think the question of morality gets more problematic. If the atomic bombings were one-off events, rare interventions to end the war, then it might (for some) be compelling to say that they were worth the price of crossing over some kind of line regarding the deliberate burning of civilians to death en masse. But if they were instead the continuation of a well-established policy of burning civilians to death en masse, then the moral question gets much broader. The question changes from, Was it morally justified to commit a civilian massacre two times?, to Was it morally justified to make civilian massacre a standard means of fighting the war? 

I want to state explicitly that I don’t think, and I don’t want my phrasing to imply, that the answer to the above is necessarily an unequivocal “no.” There are certainly many moral frameworks that can allow for massacres (e.g. ends-justify-the-means). But I prefer to not dress this sort of thing up in euphemisms, whether we think it justified or not.  Massacre means to deliberately and indiscriminately kill people. That is what you get when you bomb densely-populated cities with weapons that cannot distinguish between civilians and members of the military. Incendiary raids and atomic bombs certainly fall in this category, whether one thinks that the circumstances required them or not.

Japanese cities destroyed by strategic bombing in World War II. More information about this map here.

Japanese cities destroyed by strategic bombing in World War II. More information about this map here.

The second place I depart is a technical one. There are several important differences between the effects of firebombing and atomic bombing. They are not, even in the case of the bombing of Japan, strictly equivalent from the point of view of their effects or their outcomes.

The Tokyo firebombing raid was a relatively slow (compared to an atomic bomb), massively-distributed attack. The Tokyo raid involved hundreds of B-29 bombers arriving and attacking over the course of several hours. Such massive groups of B-29s could be heard and tracked from a considerable distance. They spread their bombs over a large area of the city, with the goal of creating a mass conflagration that would be impossible to control. They could be fought against with interceptors and anti-aircraft guns; air-raid alarms could be sounded; civilians could flee to shelter, or outside of the city itself.  This is not to imply that any of these strategies were necessarily effective, and it does not necessarily make firebombing raids any more “humane.” But it does change the outcome quite a bit, when compared to an atomic bomb attack.

The atomic bombing raids of Hiroshima and Nagasaki were fast, near-instantaneous attacks. They involved a single B-29 weather plane in advance, and then two or three B-29s approaching the city, one with the bomb itself. This means that effective air-raid warning was minimal, because it was not possible to distinguish an atomic bomb attack from a reconnaissance or weather flight, all of which were common by that late stage in the war. (And obviously any hope of detecting an atomic bomb attack was impossible prior to Hiroshima.)

Drawing by Goro Kiyoyoshi of his memories of the Hiroshima attack. "I got on a streetcar of the Kabe line about 8:10 AM. The door was open and I was standing there. As I heard the starting bell ring, I saw a silver flash and heard an explosion over the platform on which l had just walked. Next moment everything went dark. Instinctively I jumped down to the track and braced myself against it. Putting a handkerchief to my mouth, I covered my eyes and ears with my hands."

Drawing by Goro Kiyoyoshi of his memories of the Hiroshima attack. “I got on a streetcar of the Kabe line about 8:10 AM. The door was open and I was standing there. As I heard the starting bell ring, I saw a silver flash and heard an explosion over the platform on which l had just walked. Next moment everything went dark. Instinctively I jumped down to the track and braced myself against it. Putting a handkerchief to my mouth, I covered my eyes and ears with my hands.” From Unforgettable Fire: Drawings by Atomic Bomb Survivors (1977).

The primary acute effects of the atomic bombs were blast and thermal radiation. The former travels at the speed of sound, the latter significantly faster. (The rays are transmitted at more or less the speed of light, but the intensity and duration of the thermal pulse is a more complex phenomena and unfolds over the course of several seconds.) The blast knocks down buildings. The thermal radiation heats and burns. Both contribute to the starting of fires — the thermal radiation directly (for certain materials), the blast wave indirectly by knocking over flammable materials, stoves, candles, etc. After Hiroshima there was a significant firestorm, as with incendiary bombing, but there was not after Nagasaki. There was no effective preparation for such an attack — perhaps if they had the foresight of some later Civil Defense techniques, some lives could have been saved (different shelter types did affect the fatality rates significantly, even close in to the zero point), but obviously this was not quite in the cards during the war itself, when the atomic bomb was such a novelty. There was no time for shelters, no time to flee the city, no time even for real comprehension of what was happening — a bright light followed by a crushing blast, followed by fire. For those who survived the blast and fire, there were radiation effects, if they were with a few kilometers of the epicenter. This could range from acute radiation sickness and death with several weeks, to an increased cancer risk over the course of their lives.

Are the atomic bomb effects significantly different from firebombing to warrant putting them into different ethical or moral categories? One could argue the point either way. I tend to think that they are both pretty terrible forms of suffering, but they are not identical. In many ways the atomic bombing effects were significantly worse for the people living in the target cities — all of the suffering of firebombing accelerated, with a few new terrors added into the mix, and with less warning.

Table from a 1963 Office of Civil Defense report, "Survey of the Thermal Threat of Nuclear Weapons," by Jack C. Rogers and T. Miller. These numbers are not necessarily authoritative, but they give some indication of the relative mortality rates differences I am talking about.

Table from a 1963 Office of Civil Defense report, “Survey of the Thermal Threat of Nuclear Weapons,” by Jack C. Rogers and T. Miller. These numbers are not necessarily authoritative, but lay out the situation well: atomic bombs have much higher mortality and casualty rates per square mile than firebombing, but destroy proportionally smaller amounts of area.

But the equivalence argument also misses some important differences in how deadly the atomic bombs were. The firebombing of Tokyo did, indeed, kill the most people of any air raid in history — from 80,000 to over 100,000 dead in a single raid. But the city of Tokyo had some 5 million people living in it. In the areas targeted, there were 1.5 million people living. So that means that it killed no more than 2% of the total population of the city, and no more than 7% of the people who lived in the targeted areas. The bombing of Hiroshima killed between 90,000 and 160,000 people in a city of 345,000 or so. So that is a fatality rate of 26-46%, depending on whose fatality estimates you go with. The bombing of Nagasaki killed between 39,000 to 80,000 people in a city of 260,000 people or so. So that is a fatality rate of 15-30%.

So to put it another way, the Hiroshima bombing was around 5 times more deadly than the Tokyo raid per capita, and the Nagasaki bombing was maybe 4 times more deadly. The total number dead is similar in all three cases, but the total number of people possible to kill in Tokyo was much higher than the number of people in Hiroshima and Nagasaki.

This isn’t the whole story, though. There is a subtle technical difference mixed in here. Firebombing on par with the Tokyo raid spread a moderate chance of death over a large area. The atomic bombs dropped in World War II spread a very high chance of death over a relatively small area. So depending on the target in question, the difference in fatalities might or might not matter. The Hiroshima bomb was perfectly capable of killing something like half of the city — but it was a pretty small city, compared to Tokyo. Tokyo has areas of incredibly high density, but also large areas of relatively moderate to low density.

So why does this matter? From an ethical standpoint, I’m not sure it does. The targeting of civilians for mass destruction seems to be the core ethical issue, whether you do this by means of fire, neutrons, or toxic gas. But I do think we end up underestimating the effects of the atomic bombs if we see them as exactly equivalent to firebombs. There is an error in seeing the atomic bombs as just an expeditious form of firebombing — it both overstates the deadliness of firebombing while understating the deadliness of atomic bombs.

This map gives a rough indication of the methodology used to construct the casualty estimates for a Little Boy bomb targeted on World War II Tokyo. Percentages are expected average fatality rates. The actual method used (see below) used many more gradations of difference. One can see, though, the way in which the most intense of the effects of the atomic bomb are highly localized relative to the total size of Tokyo.

This map gives a rough indication of the methodology used to construct the casualty estimates for a Little Boy bomb targeted on World War II Tokyo. Percentages are expected average fatality rates. The actual method used (see below) used many more gradations of difference. One can see, though, the way in which the most intense of the effects of the atomic bomb are highly localized relative to the total size of Tokyo. The underlying population density map of Tokyo comes from the very useful Japanairraids.org.

All of this is what led me to the question I opened with: What if, in some hypothetical alternative universe, instead of launching a firebombing raid in early March 1945, the US was able to drop the Little Boy atomic bomb onto Tokyo? What would the casualties have been for that raid?

Obviously an exact answer is not possible. But we do have population density maps of Tokyo, and we do have records on the relationship between distance from “ground zero” and percentage of population killed. There are lots of uncertainties, here, regarding the types of buildings, the differences in geography, and other things that are hard to estimate. But let’s do a rough estimation.

If we transpose the effects of Hiroshima — a 15 kiloton bomb detonated around 1,968 feet above the ground — to the population densities of Tokyo, what is the result? I don’t want to clog up the blog post with a detailed explanation of the methodology I’ve used, so I’m putting it at the end with the footnotes. The basic gist of it was this: I took a population density map of Tokyo from 1940, divided the different density areas into different layers in Photoshop, then selected radii based on bomb effects and did pixel counting. I used all of this to come up with rough minimum-maximum estimates of how many people lived in areas at different regions from the bomb blast, and then multiplied those population counts against known average fatality/casualty rate data taken from Hiroshima.

I looked at two ground zeros, to further emphasize the intense locality of a Hiroshima-sized atomic bomb attack (compared to a firebombing raid). If targeted on the moderately-dense Honjo area (which is more or less the center of the firebombing attack), one could roughly expect there to be between 213,000 and 344,000 fatalities, and between 442,000 and 686,000 injuries. This is the ground zero shown in the above image. If you move it north-west by only 1 km, though, to the more densely populated Asakusa area, the numbers change to 267,000 to 381,000 dead and 459,000 to 753,000 injured.

So if the Hiroshima bomb had been dropped on Tokyo, it probably would have destroyed less area than the March 1945 Tokyo firebombings — something like 5 square miles, compared to the 15 square miles destroyed by firebombing. However it would have killed between two and four times as many people who died in the firebombings, and injured possibly fewer or the same amount of people.

These numbers seem roughly plausible to me, even given all of the uncertainties involved, and they align with the rough guess one would make from the relative area destruction and casualty rates cited earlier. It is of note that the shifting of an atomic bomb’s aiming point can increase total casualties by several tens of thousands of people in a city the density of Tokyo; firebombing is probably not quite as dependent on any given aiming point, given how much lower the accuracy was.

Finally, it is worth noting that the Tokyo firebombing was much more fatal than most of the other firebombing raids. As the first low-altitude, massed night B-29 incendiary raid, against Japan’s highest-density city, it was especially fatal. Later raids killed, on average, orders of magnitudes less, both for the reasons given at the beginning (e.g. fleeing when you hear hundreds of B-29s in the distance), and because of much lower population densities. Had Hiroshima been firebombed, the fatalities would have certainly been much lower than the atomic bombings, because the Tokyo case is in fact an anomalously high one.

Atomic bombings may be ethically no better or worse than firebombing raids like Tokyo, but to regard them as simply an expedient form of firebombing misses a key point about their relative deadliness: If you have to pick, and you get to pick, one should choose to be firebombed, not atomic bombed — unless you know exactly where the bombs are going to go off.

Click for the full casualty calculation methodology.

Notes
  1. On this, see esp. Michael Gordin’s Five Days in August, and, perhaps,  my review of it. []