Posts Tagged ‘Oak Ridge’

Meditations

Feynman and the Bomb

Friday, June 6th, 2014

Richard Feynman is one of the best-known physicists of the 20th century. Most of those who know about him know he was at Los Alamos during the Manhattan Project — some of the best “Feynman stories” were set there. But Feynman’s own stories about his wartime hijinks were, like most of his stories about himself, half just-for-laughs and half lookit-mee! Feynman’s always got to either be a lucky average Joe, or the one brilliant mind in a sea of normals. His Los Alamos antics are mostly just tales of a genius man-child running around a secret laboratory, picking safes and irritating security guards. They aren’t very good gauges of what he actually did towards making the bomb. So what did Feynman actually do with regards to making the bomb? And does it matter, for thinking about his later career, especially the work that won him a Nobel Prize two decades later? 

Los Alamos colloquium from 1946, featuring (foreground, from left-to-right), Norris Bradbury, J. Robert Oppenheimer, John Manley, Richard Feynman, and Enrico Fermi. This version is cropped from the scanned copy at the Emilio Segrè Visual Archives. I will note that unlike the more common copies of this photo that have circulated, you can actually get a sense for how many other people were in the room — it looks like a really packed house.

Los Alamos colloquium from 1946, featuring (foreground, from left-to-right), Norris Bradbury, J. Robert Oppenheimer, John Manley, Richard Feynman, and Enrico Fermi. This version is cropped from the scanned copy at the Emilio Segrè Visual Archives. I will note that unlike the more common copies of this photo that have circulated, you can actually get a sense for how many other people were in the room — it looks like a really packed house.

Feynman’s own stories of his wartime work are centered around things other than the work itself. So he describes doing calculations, but doesn’t really say what they were for. He describes going to Oak Ridge, but only as a pretext for a story about dealing with generals and engineers. He describes the Trinity test, but a lot of that is about his claim to being the only person who saw it without welding glass on. And so on. These give glimpses, but not a very complete picture.

The historian of physics (and my advisor) Peter Galison wrote an article on “Feynman’s War” several years back, looking closely at what it actually was that Feynman was doing at the lab, and how it played into the style that he later became famous for in physics.1 Galison argues that Feynman’s postwar work is uniquely characterized by being “modular, pictorial, and proudly unmathematical.” He contrasts this with the work of several of his contemporaries, including Julian Schwinger, who came up with equivalent solutions to the same physical problems but through a very different (much more mathematical) approach. Feynman’s famous diagrams, which had a huge influence on the teaching and practice of postwar physics, exemplify this approach. What in Schwinger and Tomonaga’s hands (the other people Feynman shared his Nobel Prize with in 1965) was solvable only through massive, lengthy, laborious math could, in Feynman’s hands, be solved through a series of clever diagrams which came up with equivalent results. Feynman’s solutions to quantum electrodynamics weren’t the only way to do it — but they were easier to comprehend, to teach, and to apply to new questions.

The first Feynman diagram, published in R. P. Feynman, "Space—Time Approach to Quantum Electrodynamics,"Physical Review 76 (1949), 769-789, on 772.

The first published Feynman diagram, from Richard P. Feynman, “Space-Time Approach to Quantum Electrodynamics,”Physical Review 76 (1949), 769-789, on 772.

OK, so what does this have to do World War II? Well, Galison’s argument is that you can see the same sort of thinking at work in what Feynman did at Los Alamos, and he argues that it is during the war that he really started applying this mode of physics. He divides Feynman’s work into several “projects.” They were:

  • Neutron measurements for determining critical mass (including the famous “tickling the dragon’s tail” experiment” involving creating brief, barely-subcritical masses)
  • Work on the “Water Boiler” reactor at Los Alamos, which provided further data on nuclear chain reactions
  • Work as a safety supervisor at Oak Ridge, Tennessee, at Oppenheimer’s request (which in his own writings is distilled down to a single humorous anecdote where Feynman is simultaneously clueless and brilliant)
  • Developing formulae relating to criticality and implosion efficiency (including the Bethe-Feynman formula)
  • His work on the hydride bomb, an abortive, Teller-inspired approach to make a “cheaper” fission weapon which involved devilishly difficult calculation (because not all of the neutrons produced in the weapon would be of the same energy)

Galison argues that in each of these instances, you can see the germs of his later approaches. He credits this to both Feynman’s own personal scientific style and inclinations as a theorist (Feynman didn’t seem to like to work with fundamental equations, but with “shortcuts” that lead to quicker, more efficient solutions, for example), but also to the requirements of the wartime goal, where theorists had to come up with tangible, practical results in a very short amount of time.  For example, Galison notes that the formulae relating to how the implosion bomb worked “brought the abstract differential equations to the bottom line: how hot, how fast, how much yield?” The practical needs of the war favored a particular “theoretical style” in general, Galison argues, one that could be most easily meshed with engineering concerns, rapid prototyping, and the lack of time to ruminate on fundamental physics questions.2

The "Water Boiler" reactor at Los Alamos. Source: Los Alamos Archives (12784), via Galison 1998.

The “Water Boiler” reactor at Los Alamos that Feynman worked on. Source: Los Alamos Archives (12784), via Galison 1998, p. 404.

Galison’s article is fairly technical. He goes through Feynman’s work (what of it that is declassified, anyway) and tries to follow his thinking in a very “internal” way, and then match that up with the requirements imposed by the specific wartime context. If you are well-versed in physics you will probably find the details interesting. I’m more of a big-picture person myself, and I like the structure of Galison’s argument even if I don’t feel fully capable of digesting all of the physics involved. One small example of Galison’s work can probably suffice. Feynman was sent to Oak Ridge, as noted, to serve as a safety supervisor. He was taking over for Robert Christy, who got pneumonia in April 1944. The safety question was not a general one, but a very specific one: how many barrels of uranium (in various degrees of enrichment) could be safely stored in a room without running a risk of a criticality accident? Feynman himself relates the problem like this in his famous bit, “Los Alamos from Below” (reproduced in Surely You’re Joking, Mr. Feynman):

It turned out that the army had realized how much stuff we needed to make a bomb — twenty kilograms or whatever it was — and they realized that this much material, purified, would never be in the plant, so there was no danger. But they did not know that the neutrons were enormously more effective when they are slowed down in water. In water it takes less than a tenth — no, a hundredth — as much material to make a reaction that makes radioactivity. It kills people around and so on. It was very dangerous, and they had not paid any attention to the safety at all.

In Feynman’s account, he more or less walks in and figures out what the problems were and how to fix them. The story is about ignorance — in particular systemic ignorance due to secrecy — and Feynman’s attempts to cut through it.

Feynman's diagrammatic sketch of storage of barrels of uranium at Oak Ridge, prepared for his "Safety Report." Source: Galison 1998, p. 408.

Feynman’s diagrammatic sketch of storage of barrels of uranium at Oak Ridge, prepared for his “Safety Report.” Source: Galison 1998, p. 408.

Galison’s account is more technical. Feynman told them that pretty much any amount of unenriched uranium could be stored safely in the facility, but that 5% enriched and 50% enriched had to be handled fairly carefully. 50% enriched uranium in water, for example, would dangerous at a mere 350 grams of material unless there was a neutron absorbing material (cadmium) present. Feynman developed a series of safety recommendations for all grades of enrichments, and had to use reasonable safety margins to make up for potential errors in the calculations. He became the “point man” for safety questions involving fissionable materials, and developed (as Galison puts it) “visualizable” methods for answering basic (but important) questions about hypothetical systems (e.g. for “Gunk storage tanks,” whether they had to be coated with cadmium or not). His methods, Feynman himself emphasizes, were “only approximate, as accuracy has been sacrificed to speed and simplicity in calculation” — the kind of computational “short cut” that was both needed for the practical requirements, but also was common to Feynman’s general approach to physics. Galison concludes the section thus:

The admixture of approximation methods, neutron diffusion, nuclear cross sections, floods, fires and wooden walls marked Feynman’s correspondence with the Oak Ridge engineers. From April of 1944 to September 1945, whatever else Feynman was doing, he was also deeply enmeshed in the barely-existing field of nuclear engineering. Out of this interaction came characteristic rules and modular reasoning: visualizable, approximate, from-the-ground-up calculations applied to neutrons, pans, sheds and sludge. Visionary statements reinterpreting established laws of physics ceded to the exigencies of living in a world he had to reach outside the home culture of theoretical physics as he knew it before the war. Now a billion dollar plant was churning out U-235, and only a calculation stood between thousands of workers and nuclear disaster.

Which is a lot more serious-sounding that Feynman’s own somewhat jokey accounts of the work. In the latter part of the article, Galison connects all of these methods for thinking — and sometimes even the specific problems — with Feynman’s postwar work, showing the influence of his time at Los Alamos.

Diagram of neutron fluctuations from a report by F. de Hoffmann, R.P. Feynman, and R. Serber. Galison notes: "Significantly, Feynman and his collaborators captured the situation in a spacetime diagram drawn with time in the vertical direction and space horizontal. Such an image must be kept in mind when viewing Feynman's early postwar spacetime 'Feynman diagrams,' where again particles are absorbed, emit other particles, and scatter as reckoned by a concatenation of independent algebraic rules." Galison 1998, 405-406.

Diagram of neutron fluctuations from a report by F. de Hoffmann, R.P. Feynman, and R. Serber. Galison notes: “Significantly, Feynman and his collaborators captured the situation in a spacetime diagram drawn with time in the vertical direction and space horizontal. Such an image must be kept in mind when viewing Feynman’s early postwar spacetime ‘Feynman diagrams,’ where again particles are absorbed, emit other particles, and scatter as reckoned by a concatenation of independent algebraic rules.” Galison 1998, 405-406.

Feynman stayed at Los Alamos until the fall of 1946, when he relocated to Cornell University. He never worked on weapons again, but he never took a particularly strong stand on it. What did Feynman think about nuclear weapons, and his role in making them? There is some evidence in his private correspondence, much of which was published not too long ago,3 but it is scant. Most of his responses to inquiries were along the lines of “we feared the Nazis would get one first.”4That’s it. No comment on their use at all, or the end of the war, or any of the other common responses from Los Alamos veterans. When asked in the 1970s about his thoughts on nuclear weapons in general, he demurred: “Problems about the atomic bomb and the future are much more complicated and I cannot make any short  statement to summarize my beliefs here.”5

Feynman gave an interview in 1959 where he was asked directly about the bomb. His response was a little lengthier then, but still said very little:

Now, with regard to our own things as human beings, naturally—I myself, for example—worked on the bomb during the war. Now how do I feel about that? I have a philosophy that it doesn’t do any good to go and make regrets about what you did before but to try to remember how you made the decision at the time. …if the scientists in Germany could have developed this thing, then we would be helpless, and I think it would be the end of the civilization at that time. I don’t know how long the civilization is going to last anyway. So the main reason why I did work on it at the time was because I was afraid that the Germans would do it first, and I felt a responsibility to society to develop this thing to maintain our position in the war.6

This, of course, ignores the question of “so why did you continue when the Germans were known not to have made much progress?” and much more.

Charles Critchfield, Richard Feynman, J. Robert Oppenheimer, and an unidentified scientist, at Los Alamos. Source: Emilio Segrè Visual Archives, via Los Alamos.

Charles Critchfield, Richard Feynman, J. Robert Oppenheimer, and an unidentified scientist, at Los Alamos. Source: Emilio Segrè Visual Archives, via Los Alamos.

During the interview, Feynman was asked, point blank, whether he worked on any secret projects. Feynman said no, and that this was “out of choice.” Pushed further, he elaborated:

I don’t want to [do secret work] because I want to do scientific research—that is, to find out more about how the world works. And that is not secret; that work is not secret. There’s no secrecy associated with it. The things that are secret are engineering developments which I am not so interested in, except when the pressure of war, or something else like that, makes me work on it. … Yes, I am definitely anti-working in secret projects. … I don’t think things should be secret, the people developing this. It seems to me very difficult for citizens to make a decision as to what’s going on when you can’t say what you’re doing. And the whole idea of democracy, it seems to me, was that the public, where the power is supposed to lie, should be informed. And when there’s secrecy, it’s not informed. Now, that’s a naive point of view, because if there weren’t secrecy, there’d be the Russians who would find out about it. On the other hand, there’s some awfully funny things that are secret. It becomes secret that we know what the Russians are keeping secret from us, for instance, or something like that. It seems to me that things go too far in the secrecy.7

After that point in the interview, he steered away from political opinions, explaining that he had strong ones, but he didn’t think they were any more valuable than anyone else’s opinions.

There were those, of course, who did try to recruit Feynman for military work. John Wheeler, his doctoral advisor at Princeton, and the man who had roped him into Los Alamos in the first place, appealed to him strongly to join the Princeton work on the hydrogen bomb (Matterhorn) in late March 1951. Wheeler had heard the Feynman was trying to spend his sabbatical in Brazil, but Wheeler thought the chance of global war was “at least 40%,” and that Feynman’s talents might be better spent helping the country. It was a long, emotional letter, albeit a variation on one that Wheeler sent to many other scientists as well. Wheeler tried to win him (and others) with flattery as well, telling Feynman that “You would make percentage-wise more difference there than anywhere else in the national picture.” In response to Wheeler’s long, many-pointed letter, Feynman simply responded that he didn’t want to make any commitments until he found out whether the Brazil idea would work out. End of story. Nothing specific about the hydrogen bomb one way or the other.

High resolution detail of Feynman's Los Alamos security badge photograph. A this resolution you can see a lot more strain on his face than the one I posted awhile back. Source: Los Alamos National Laboratory Archives.

High-resolution detail of Feynman’s Los Alamos security badge photograph. At this resolution you can see potentially more strain on his face than the one I posted awhile back. Source: Los Alamos National Laboratory Archives.

What should we make of this? Feynman is a complicated man. Much more complicated than the zany stories let on — and I suspect the stories themselves were some kind of defense mechanism. As Feynman’s friend Murray Gell-Mann said at Feynman’s memorial service, Feynman “surrounded himself with a cloud of myth, and he spent a great deal of time and energy generating anecdotes about himself.” They were stories “in which he had to come out, if possible, looking smarter than anyone else.”8 He was not a moralizer, though. His work on the bomb fit into his stories only as a context. He no doubt drew many lessons from his work on nuclear weapons, and he no doubt had many opinions about them in the Cold War, but he kept them, it seems, much to himself.

Oppenheimer famously said that, “In some sort of crude sense, which no vulgarity, no humor, no overstatement can quite extinguish, the physicists have known sin…” Perhaps Feynman agreed — perhaps no more humor could be wrung out of the bomb after Hiroshima and Nagasaki. Maybe it’s harder to write a zany story about the hydrogen bomb. And maybe he was just truly not interested in them from a technical standpoint, or, as he said in 1959, just didn’t think his opinions on these matters, one way or another, were worth a damn, going against the notion held by many of his contemporaries that those who made the bomb had a special knowledge and a special responsibility. To me, he’s still something of an enigma, just one that wrapped himself in jokes, rather than riddles.

Notes
  1. Peter Galison, “Feynman’s War: Modelling Weapons, Modelling Nature,” Stud. Hist. Phil. Mod. Phys. 29, No. 3 (1998), 391-434. []
  2. This is an argument that Galison also makes at length about wartime work in his 1997 book Image and Logic: A Material Culture of Microphysics, both for Los Alamos and for the MIT Rad Lab, which if you’re interested in this kind of thing, is a must-read. []
  3. Michelle Feynman, ed., Perfectly Reasonable Deviations from the Beaten Track: The Letters of Richard P. Feynman (Basic Books, 2005). []
  4. See e.g., Ibid., 268: “I did work on the atomic bomb. My major reason was concern that the Nazi’s would make it first and conquer the world.” []
  5. Ibid., 305. []
  6. Ibid., 421. []
  7. Ibid., 422-423. []
  8. James Gleick, Genius: The Life and Science of Richard Feynman (Pantheon, 1992), on 11. []
Redactions

How many people worked on the Manhattan Project?

Friday, November 1st, 2013

Everyone knows the Manhattan Project was big. But how big was it? There are lots of ways to try and convey the bigness. The size of the buildings and sites, for example. Or the cost — $2 billion 1945 USD, which doesn’t sound that big, even when converted to modern numbers (e.g. around $30 billion 2012 USD, depending on the inflator you use), since we’re used to billions being tossed around like they are nothing these days. But consider that the USA spent about $300 billion on World War II as a whole — so that means that the atomic bombs made up for a little under 1% of the cost of the entire war. Kind of impressive, but even then, it’s hard to wrap one’s head around something like “the cost of World War II.”

General Groves speaks to a group of Oak Ridge service personnel in August 1945. From the DOE. There are lots of great Oak Ridge photos from the 1940s in this Flickr set.

General Groves speaks to a group of Oak Ridge service personnel in August 1945. From the DOE. There are lots of great Oak Ridge photos from the 1940s in this Flickr set.

Another approach is to talk about how many people were involved. There are a number of various estimates floating around. Instead of focusing on those, I want to jump directly to the source: a once-secret postwar report on Manhattan Project personnel practices that includes some raw numbers on hiring.1

This report has two very interesting graphs in it. The first is this one, showing total employment by month, broken into the various important Manhattan Project categories:

Manhattan Project contractor employment by month

Let’s just take a moment to marvel at this. They went from pretty much just talking about a bomb, in theory, on paper, in late 1942, and had a project with 125,310 active employees at its peak, 22 months later. That’s a huge ramp-up.

I like this graph because it helps you see, very plainly, the progress of the project. You can see that Oak Ridge (CEW) and Hanford (HEW) construction both got rolling pretty quickly but took about a year to hit their maximums, and that all construction peaked in early 1944. At which point, operations became the main issue — running the plants. It’s interesting to compare how many more people were required for Oak Ridge operations than Hanford operations, and that the “Santa Fe Operations” — Los Alamos, et al. — barely registers on the graph. A couple thousand people at most.

You can also see how rapidly that curve starts to drop off in September 1945 — over 10,000 people left at the end of the war, a significant chunk of them being Oak Ridge operations personnel. There is then a long slumping decline until late 1946, when you start to get an up-tick. This maps on pretty well with what we know about the history of the Manhattan Project in the period before the Atomic Energy Commission took over: Groves’ hard-built empire decayed under the uncertainty of the postwar and the dithering of Congress.

This is where we get the number one usually sees cited for the Manhattan Project: 125,000 or so employees at its peak. Which is impressive… but also kind of misleading. Why? Because peak employment is not cumulative employment. That is, the number of people who work at any given company today are not the number of people who have worked there over the course of its lifetime. Obvious enough, but if one is wondering how many people did it take to make the atomic bomb, one wants to know the cumulative employment, not the number on hand at any one time, right?

Digging around a bit more in the aforementioned personnel statistics of the Manhattan Project (a thrilling read, I assure you), I found this rather amazing graph of the total number of hires and terminations by the project:

Manhattan District Contractors Hires and Terminations through 31 December 1946

Now that number on the left, the total hires, is a pretty big one — over 600,000 total. Unlike the other graph, I don’t have the exact figure for this, but it looks to be around 610,000. That’s a huge number. Why would the numbers be at such odds? Because at the big sites — Oak Ridge and Hanford — there was a pretty high rate of turnover, as the “terminations” bar indicates: over 560,000 people left their jobs on the Manhattan Project by December 1946.

Some of this, of course, is because the job was done and they went home — once the construction was done, you didn’t need as many people working on construction anymore. But it’s also because even during the war, there was a considerable amount of people either quitting or getting fired. People left their jobs all the time, at all times during the war. As the report indicates, the reasons and rates varied by site. For construction at Hanford, they had an average monthly turnover rate of 20%, with a ratio of resignations to discharges set at 3 to 1. Of those who resigned, 26% did so because of illness, 19% were to move to another location (which could be a lot of things), 13% cited poor working conditions, 13% said there was an illness in the family, 14% had got another job somewhere else, 7% cited the poor living conditions, 6% got drafted or otherwise joined the military, and 2% complained about wages. Of those who were discharged, about a quarter of the time it was because they were an “unsatisfactory worker,” and the rest of the time it was because of chronic absenteeism. For construction at Oak Ridge, the average turnover rate was 17%, with mostly the same reasons given, though the resignations to discharge ratio was 2 to 1. (More people, by percentage, complained about the living conditions at Oak Ridge than at Hanford.) For the operations at Oak Ridge, the turnover rate was 6.6%, with a resignations to discharge ration of 1.3 to 1 — of those who left, a little over 40% did so because they were fired.

A 1944 "Stay on the job" rally at J.A. Jones Construction Co. in Oak Ridge. The workers seem a little unimpressed. Source.

A 1944 “Stay on the job” rally at J.A. Jones Construction Co. in Oak Ridge. The workers seem a little unimpressed. Source.

Of course, these numbers run through the entire tenure of the Manhattan Engineer District. When most people want to know how many people it took to make the bomb, they want to know up until August 1945 or so. I don’t have exact numbers on this. However, if we take the data from the report and the graphs, and assume an average monthly turnover rate of about 17% for the entire project, we end up with about the right number total.2 Subtracting all of the people added after August 1945, we get around 485,000 total people required to make the bombs during World War II. Given how much of that employment was front-loaded (again, with a peak in June 1944), I don’t think it’s too far off to assume that probably half a million people were employed to make the bomb. Which, to put that in perspective, means that during World War II, approximately 0.4% of all Americans worked on the bomb project — about one out of every 250 people in the country at the time.

Which is pretty impressive. By contrast, I’ve seen estimates that said that the Soviets used about 600,000 people total to make their atomic bomb. Which is not too different a number, actually — a bit less impressive than one might think if one is only comparing it to the peak of the Manhattan Project. The Soviets had around 170 million people at the time, so it works out to be a pretty similar percentage of the total population as the American project. Of course, one suspects that fewer of the Soviet workers were able to quit because they didn’t like the wage and working conditions. Though I’m sure they had their own form of grim “turnover.”

Notes
  1. Manhattan District History, Book I – General, Volume 8 – Personnel (dated 19 February 1946 but with numbers that suggest later additions were made. []
  2. If you want to play with the data yourself, I’ve uploaded it here as a CSV file. Some of it is extrapolated from the top graph. []
Visions

Inside K-25

Friday, May 24th, 2013

The K-25 plant at Oak Ridge was the single most expensive part of the Manhattan Project. It was cost about a fourth more than the entire Hanford site. Perhaps unsurprisingly, the building that housed it was pretty big — supposedly the largest single factory in the world under one roof, at the time that it was built.

I had thought about creating some kind of little graphic comparison to show you how big it was — you know, putting it next to The Pentagon and other large buildings —  and then I realized that I wouldn’t really be flexing my geek cred, or taking advantage of a web medium, if I didn’t make a little custom mashup instead. So, I present for you a quick little app that I’m calling, How Big Was K-25?, where you can drag the footprint of K-25 onto anywhere in the world to make a size comparison:

(If you only see a blank spot above,  or if you want to view it larger than it is displayed in the blog post, then click here to open the page in its own window. Note that there is a “rotate” button in the upper-left corner, if you want to re-arrange K-25.)

And yet… despite its cost, despite its size, when one thinks of images of the Manhattan Project, even images of Oak Ridge, views of the inside K-25 aren’t what comes to mind. We’ve all seen the images of the Y-12 “racetrack,” and many of us have seen images of the face of the B-Reactor, but what does a gaseous diffusion plant look like?

A reader asked this question in a comment on last week’s post, and it got me scratching my head, and asking around on Twitter. I got enough interesting results that I felt it was worth a post in its own right, as opposed to just a long comment. I can think of two major reasons why this sort of thing isn’t as common in the photos of the bomb project, which I’ll include at the end.

These photos were mostly taken by Ed Westcott, the official Oak Ridge photographer during the war (and after), and are hosted by the Oak Ridge Public Library. (Special thanks to the American Museum of Science and Energy for pointing this resource out to me!)

 

Overall aerial view of K-25 area

Overall aerial view of K-25 area 

Close aerial view of K-25 Building

Close aerial view of K-25 Building

First we fly into the plant, in some typical pictures of its U-shaped bulk, but I like the juxtoposition as we get closer and closer. You can see some trucks at the very bottom center of the lower image, to get a sense of scale. It’s big.

Cleanliness control gate

Cleanliness control gate

We think of the signs in such an installation to be all about security, but these ones are all about cleanliness. This appears to be some kind of basic air-lock. I find that somewhat charming, though one knows that grime is something you probably don’t want in a gaseous diffusion plant, where every atom counts!

Control panels in master control room

Control panels in master control room

K-25 control room

K-25 control room

Two control rooms. I find the one on the bottom to be a wonderfully haunting photograph. I love the difference between the size of the room and the tininess of that table. It must have been a tremendous pain to keep something as interconnected and complex as the K-25 plant humming around the clock.

K-25 typical withdrawal alley

K-25 typical withdrawal alley

Front elevation of gaseous diffusion cells in K-303-1

Front elevation of gaseous diffusion cells in K-303-1

Air compressors and water pumps from K-1101 Building

Air compressors and water pumps from K-1101 Building

Conditioning filter test

Conditioning filter test

Stage floor in K-306-6 showing vacuum testing

Stage floor in K-306-6 showing vacuum testing

Interior of gaseous diffusion cell structure

Interior of gaseous diffusion cell structure

These ones all seem to show the insides of various stages of the cascade. As you can see from this plot plan, K-25 consisted of lots of individual “cells” that were linked together. Its vastness and bulk is mostly iteration of stages, like most (all?) uranium enrichment facilities — each stage doing a tiny part of the overall work.

Two workers standing by a gaseous diffusion cell

Two workers standing by a gaseous diffusion cell

A solvent degreaser worker showing pipe assembly in K-1400

A solvent degreaser worker showing pipe assembly in K-1400

Typical filter in gaseous diffusion cell

Typical filter in gaseous diffusion cell

Typical setting of process pump

Typical setting of process pump

These ones I like because they help give you some sense of the size and nature of the equipment involved. Gaseous diffusion plants look like various pipes and pumps and big vessels. In a way, they are somewhat generic looking, which may be why they aren’t usually used to illustrate uranium enrichment, as I’ll speculate on a little bit below.

Lastly, a few color images, probably taken at a later date, from the Manhattan Project Heritage Preservation Association:

ORP-WMOR-042

ORP-WMOR-044

Both of these I like not only because of the color — how much of those paint jobs are post-1945, I don’t know — but also because the presence of people helps you get a sense of the scale of those vessels. They seem larger than the ones in the other photographs, so they may be later additions. Thanks to Jeffrey Lewis for pointing this out to me.


So why are these images dreadfully underrepresented in our collective imagination regarding the Manhattan Project? I offer three possible reasons.

One is the familiar problem of classification: gaseous diffusion was highly classified after the war. Unlike the electromagnetic enrichment method, or the basics of reactor operation, it wasn’t declassified in the early 1950s. There are still lots of things that are tied up tight as far as classification is concerned, despite the fact that gaseous diffusion is a pretty old technology, and arguably not the technology of choice for a modern proliferator (too expensive, too difficult).

Another is that gaseous diffusion arguably wasn’t as significant to the war effort as electromagnetic enrichment (though it wasn’t exactly insignificant, either); it came online a lot later, and really wasn’t perfected until after the war ended. Also, in comparison to the electromagnetic method, it also lacked as enthusiastic a booster as Ernest O. Lawrence, who was nothing if not entrepreneurial in promoting technologies that he was involved with.

And lastly, a potential other reason though is that as a concept it’s a bit harder to grasp, a bit hard to explain, and a bit harder to display visually, than other methods of enrichment. Electromagnetic enrichment is pretty easy to understand, and easy to diagram. And once you’ve seen how it works, suddenly images of Calutrons make a lot of sense — ah, there’s that C-shape. Rope them around a magnet and you’re done. It corresponds with nice intuitive notions of classical mechanics, and can be the source of all sorts of plain-language analogies (throwing heavier or lighter baseballs, for example).

Gaseous diffusion involves shooting gas through specialized barriers, relying on slightly different transit times, and visually, looks like just so many big tubs connected to one another. Internally it looks a lot like a lot of other anonymous industrial plants; its size, and its radioactivity, are perhaps the only things that make it obvious that it isn’t some kind of anonymous solvent factory. The kinds of diagrams explaining its operation that circulated in the early days were not exactly stimulating to thought, either.


All of this discussion of K-25, of course, is thoroughly in the past tense. Most of K-25 has been torn down; demolished. The DOE has been fairly unenthusiastic about preserving any of the K-25 buildings, despite their historical relevance. I think this is really, truly too bad. Whatever one’s feelings about the Manhattan Project, destroying historical sites doesn’t really help anybody. This is one of the reasons I’m a supported of the Atomic Heritage Foundation‘s efforts to have a number of the few remaining Manhattan Project sites declared part of a new Manhattan Project National Park. Aside from the possibility of using them as the focal point for interesting interpretations of our atomic history, it’s also necessary if we’re going to expect any remnants of these buildings to still be around in generations to come, as the Manhattan Project slides out of living memory. We can argue about the meaning of these sites for years and years — but only if we still have them to argue about.

Meditations

The price of the Manhattan Project

Friday, May 17th, 2013

There’s been a little radio silence over here last week; the truth is, I’ve been very absorbed in NUKEMAP-related work. It is going very well; I’ve found some things that I thought were going to be difficult to be not so difficult, after all, and I’ve found myself to be more mathematically capable than I usually would presume, once I really started drilling down in technical minutiae. The only down-side of the work is that it is mostly coding, mostly technical, not terribly conducive to having deep or original historical thoughts, and, of course, I’ve gotten completely obsessed with it. But I’m almost over the hump of the hard stuff.

Two weeks ago, I made a trip out to the West Coast to hang out with the various wonks that congregate at the Center for Nonproliferation Studies at the Monterey Institute for International Studies. This was at the behest of Stephen Schwartz, who teaches a class over there and had me come out to talk to them about nuclear secrecy, and to give a general colloquium talk.

Atomic Audit

Stephen became known to me early on in my interest in nuclear things for his work in editing the book Atomic Audit: The Costs and Consequences of U.S. Nuclear Weapons Since 1940 (Brookings Institute, 1998). This is one of these all-time useful reference books; it is the only book I’ve read, for example, that has anything like a good description of the development of US nuclear secrecy policies. And the list of contributors is a who’s-who of late 1990s nuclear scholarship. The book includes really detailed discussions about how difficult it is to put a price tag on nuclear weapons spending in the United States, for reasons relating both to the obvious secrecy issue, but also the fact that these expenses have not really been disentangled from a lot of other spending.

I’ve had a copy of the book for over a decade now, and it has come in handy again and again. I’m not a numbers-guy (NUKEMAP work being the exception), but looking at these kind of aggregate figures helps me wrap my head around the “big picture” of something like, say, the Manhattan Project, in a way that is often lost by the standard historical approach of tight biographical narratives. Of the $2 billion spent on the Manhattan Project, where did it go, and what does it tell us about how we should talk about the history of the bomb?

Here is a breakdown of cost expenditures for the Manhattan Project sites, through the end of 1945:

Site/Project 1945 dollars 2012 dollars %
OAK RIDGE (Total) $1,188,352,000 $18,900,000,000 63%
K-25 Gaseous Diffusion Plant $512,166,000 $8,150,000,000 27%
Y-12 Electromagnetic Plant $477,631,000 $7,600,000,000 25%
Clinton Engineer Works, HQ and central utilities $155,951,000 $2,480,000,000 8%
Clinton Laboratories $26,932,000 $430,000,000 1%
S-50 Thermal Diffusion Plant $15,672,000 $250,000,000 1%
HANFORD ENGINEER WORKS $390,124,000 $6,200,000,000 21%
SPECIAL OPERATING MATERIALS $103,369,000 $1,640,000,000 5%
LOS ALAMOS PROJECT $74,055,000 $1,180,000,000 4%
RESEARCH AND DEVELOPMENT $69,681,000 $1,110,000,000 4%
GOVERNMENT OVERHEAD $37,255,000 $590,000,000 2%
HEAVY WATER PLANTS $26,768,000 $430,000,000 1%
Grand Total $1,889,604,000 $30,060,000,000

I’ve taken this chart from here. The “current dollars” are 2012 dollars, with a “production line” labor deflator used (out of all of the options here, it seemed like the most appropriate to the kind of work we’re talking about, most of which was construction).

To break the numbers down a bit more, K-25, Y-12, and S-50 were all uranium enrichment plants. Hanford was for plutonium production. “Special operating materials” refers to the raw materials necessary for the entire project, most of which was uranium, but also highly-refined graphite and fluorine, among other things. Los Alamos was of course the design laboratory. The heavy water plants were constructed in Trail, British Columbia, Morgantown, West Virginia, Montgomery, Alabama, and Dana, Indiana. Their product was not used on a large scale during the war; it was produced as a back-up in case graphite proved to be a bad moderator for the Hanford reactors.

I’m a visual guy, so I of course immediately start looking at these numbers like this:

Manhattan Project costs chart

Which puts things a little more into proportion. The main take-away of these numbers for me is to be pretty impressed by the fact that some 80% of the money was spent on the plants necessary producing fissile materials. Only 4% went towards Los Alamos. And yet, in terms of how we talk about nuclear weapons and the Manhattan Project, we spend a huge amount of the time talking about the work at Los Alamos, often with only token gestures to the work at Hanford and Oak Ridge as the “next step” after the theory had been worked out.

We can also break those numbers down a little finer, by turning to another source, Appendix 2 of Richard Hewlett and Roland Anderson’s The New World. There, they have costs divided into “plant” and “operations” costs:

Site/Project Plant Operations Plant %
OAK RIDGE (Total) $882,678,000 $305,674,000 74%
K-25 Gaseous Diffusion Plant $458,316,000 $53,850,000 89%
Y-12 Electromagnetic Plant $300,625,000 $177,006,000 63%
Clinton Engineer Works, HQ and central utilities $101,193,000 $54,758,000 65%
Clinton Laboratories $11,939,000 $14,993,000 44%
S-50 Thermal Diffusion Plant $10,605,000 $5,067,000 68%
HANFORD ENGINEER WORKS $339,678,000 $50,446,000 87%
SPECIAL OPERATING MATERIALS $20,810,000 $82,559,000 20%
LOS ALAMOS PROJECT $37,176,000 $36,879,000 50%
RESEARCH AND DEVELOPMENT $63,323,000 $6,358,000 91%
GOVERNMENT OVERHEAD $22,567,000 $14,688,000 61%
HEAVY WATER PLANTS $15,801,000 $10,967,000 59%
Grand Total $1,382,033,000 $507,571,000 73%

They do not define how they differentiated between “plant” and “operations” expenses, but the most plausible guess is that the former are various start-up costs (e.g. construction) and one-off costs (e.g. big purchases of materials) and the latter are day-to-day costs (general labor force, electricity, etc.).

Looking at that percentage can tell you a bit about how much of the Manhattan Project was the building of a weapons production system as opposed to building three individual weapons. Nearly three-fourths of the expense was for building a system so large that Niels Bohr famously called it country-sized factory.1

The K-25 gaseous diffusion plant: the single largest and most expensive Manhattan Project site.

The K-25 gaseous diffusion plant: the single largest and most expensive Manhattan Project site.

Another way to look at this is to say that we usually talk about the atomic bomb as project focused on scientific research. But one could arguably say that it was more a project of industrial production instead. This is actually quite in line with how General Groves, and even J. Robert Oppenheimer, saw the problem of nuclear weapons. Oppenheimer, in testimony before Congress in 1945, went so far as to phrase it this way:

I think it is important to emphasize [the role of industry in the Manhattan Project], because I deplore the tendency of myself and my colleagues to pretend that with our own hands we actually did this job. We had something to do with it. If it had not been for scientists, there would have been no atomic bomb; but if there had been only scientists, there also would be no atomic bomb.

This is actually a very important point, and one which shines light onto a lot of other questions regarding nuclear weapons. For example, one of the questions that people ask me again and again is how close the Germans were to getting an atomic bomb. The answer is, more or less, not very close at all. Why not? Because even if their scientific understanding was not too far away — which it was not, even though they were wrong about several things and behind on several others — they never came close to the stage that would be necessary to turn it into an industrial production program, as opposed to just a laboratory understanding. That sheer fact is much more important than whether Heisenberg fully understood the nature of chain reactions or anything like that.

Why do we think of the bomb as a scientific problem as opposed to an industrial one? There are perhaps a few answers to this. One is that from the beginning, the bomb came to symbolize the ultimate fruits of scientific modernity: it was seen as the worst culmination of all of those centuries of rational thought. What grim irony, and what a standard story, that knowledge could lead to such ruin? Another reason is that scientific adventure stories are more interesting than industrial adventure stories. It is much more fun to talk about characters like Szilard, Oppenheimer, and Feynman running around trying to solve difficult logic problems in a desperate race against time, than it is to talk about the difficulties inherent to the construction of very large buildings.

Finally, though, there is the issue of secrecy. The scientific facts of the atomic bomb, especially the physics, were the most easily declassifiable. As discussed in a previous post (with many nods towards the work of Rebecca Press Schwartz), one of the main reasons the Smyth Report was so physics-heavy is because the physics was not terribly secret. Nuclear chain reactions, the idea of critical mass, the basic ideas behind uranium enrichment and reactors: all of these things were knowable and even known by physicists all over the world well prior to the bombing of Hiroshima and Nagasaki. The really hard stuff — the chemistry, the metallurgy, the engineering “know-how,” the specific constructions of the massive fissile-material production plants — was silently omitted from official accounts.

Looking at the costs of the bomb help rectify this perception a bit. It still doesn’t get us outside of the heroic narratives, for they are very appealing, but it can help us appreciate the magnitude of what is left out of the standard story.

Notes
  1. Bohr reportedly told Teller upon seeing Los Alamos and hearing about the entire project: “You see, I told you it couldn’t be done without turning the whole country into a factory. You have done just that.” []
Meditations | News and Notes

Three losses

Friday, January 25th, 2013

There were three Manhattan Project losses that I heard about over the last week that I thought were worth briefly commenting on. They highlight, in different ways, how the living history of the Manhattan Project is rapidly vanishing.

Erwin Hiebert, 1972. From the Radcliffe Archives.

Erwin Hiebert, 1972. From the Radcliffe Archives.

Erwin Hiebert had worked as a chemist at the Chicago Metallurgical Laboratory. He passed away last November, though a notice was just recently sent around. I interviewed him a few years back, though not about his bomb work (connected with doing some local Harvard history). I believe I recall him telling me he had worked with Harold Urey on diffusion research. He later became an historian of science, and this was the capacity I knew him in. He was a charming old man, very helpful, very friendly. He wasn’t a major figure on the Manhattan Project, but it’s sometimes worth remembering how many people were involved in the project other than the main, well-known scientists and the thousands of construction workers or miscellaneous technicians. I recently had a chance to look up just how many people working at the Met Lab — we normally only hear about the 20 or so people who worked on the pile, but at its height, there were around 2,000 people working at Chicago on the bomb, with some 750 of them doing it in a scientific (as opposed to administrative or construction) capacity.

Assembling the Trinity device: Louis Slotin, Herb Lehr, and — I believe, at top right — Donald F. Hornig. It looks a lot like him, to me.

Assembling the Trinity “Gadget”: Louis Slotin, Herb Lehr, and — I believe, at top right — Donald F. Hornig (magnified). It looks a lot like him, to me, but I don’t have confirmation of this. The “Gadget” is at far left, of course; on top of the box next to it is the container with its plutonium core.

Donald F. Hornig also recently passed away. He worked at Los Alamos during the war, and was heavily involved in the instrumentation work that was required for the implosion bomb. He was credited as the inventor of the triggered spark-gap switch (a “low-impedance switch”), which was the switch necessary to divert a high-voltage signal to the 32 detonators on the “Gadget” with a simultaneity tolerance of only nanoseconds. (A patent application for this switch had been filed in his name in late 1945; it was declassified and granted in 1976. Hornig told me he had no awareness of it being filed or granted when I talked to him a few years back.) He was also one of the last people in the “Trinity” tower before its detonation, checking the electrical connections, which proved to be a somewhat hair-raising experience. He describes his work at “Trinity” in some detail here. It’s worth a read:

I think I was the last person down from the tower although there might be a little bit of argument about that. I won’t go into any detail, but Oppenheimer had gotten worried about nine o’clock the night before about how easy the thing was to sabotage by anyone who really knew anything about it, and so I believe it was Kistiakowsky, Bainbridge and I who each took a turn sitting with it up on the tower. My turn came from around nine o’clock until midnight, in the midst of a violent thunder and lightning storm. You get philosophical in those circumstances. You know, either you do get hit by lightning or you don’t and either way you won’t know what happens.

He had many later achievements, including being LBJ’s science advisor.

The Oak Ridge K-25 plant in 1945.

The Oak Ridge K-25 plant in 1945.

Lastly, the K-25 plant has been completely destroyed. The Oak Ridge facility, which had been used during and after World War II to enrich uranium via the gaseous diffusion method, was the largest factory under one roof at the time it was constructed. It had been long since shut down, and, a few years back, all but one “cell” of its building had been destroyed. A number of people had been trying to keep the cell preserved as an historic site, but it came to naught. It took only 20 minutes to permanently knock down the last piece of it, the last indication of the scale of this site.

I think this is really too bad — a completely missed opportunity. I know that there are people who have mixed feelings about preserving the Manhattan Project sites — they think that they will be used as excuses to glorify the atomic bomb. I think this is entirely misguided. These sites are ambiguous and they provoke different reactions from different people. By analogy, there can be controversy over how the Enola Gay should be presented to the public, but the answer is not to melt the Enola Gay into scrap. Destroying these sorts of legacies is a permanent act, whereas the act of interpretation is an always changing one. Erasing history is not the right response to the fact that we still disagree over it. Destroying the sites where the atomic bomb was made will not change the fact that we made the atomic bomb.

The last generation of people who worked on the first atomic bombs is passing away. The bomb still exists. We should be doing more to preserve these sites, even if they make us uncomfortable, even if we are unsure how they will be used by people in the present or the future.