Redactions

The “Doubts” of General Groves (1946)

by Alex Wellerstein, published June 6th, 2012

It’s been a busy week. Yesterday I went to an interesting session hosted by the Atomic Heritage Foundation on the life and influence of Joseph Rotblat and the Pugwash movement. I learned some things I hadn’t known before. Of particular interest is that the common story about Rotblat leaving the Manhattan Project out of strong ethical convictions (he was supposedly the only person who left Los Alamos after the war in Europe had concluded without use of the bomb) is more complicated than it seems on the surface of it.

The story itself apparently wasn’t a matter of public record until Rotblat wrote an article about it for the Bulletin of the Atomic Scientists in 1985 (“Leaving the Bomb Project“), which is a lot more recent than I had guessed. Andrew Brown, whose book Keeper of the Nuclear Conscience: The Life and Work of Joseph Rotblat has just recently come out (I haven’t read it yet, but I bought a copy there), notes that Rotblat himself initially put a heavy caveat on the story: “All extraneous personal elements are left out, but their exclusion does not mean that they are unimportant.”

These “personal elements,” Brown argues, include things like the fact that Rotblat’s wife and family were stuck in Nazi and Soviet-occupied Poland, and that Rotblat, though a member of the British delegation to Los Alamos, had refused to take on either British or American nationality. This factor was overlook-able by General Groves at the explicit intervention by James Chadwick, the head of the British mission to Los Alamos, but not until Groves himself had personally interviewed Rotblat. Why would Groves care? Because he didn’t want Manhattan Project participants diffusing their bomb-making information all over the planet after the war was ended.

Why all this matters is that in fact, Brown argues, Rotblat didn’t simply leave the project… he was actually pushed out. The reasons are part of complex Manhattan Project diplomatic history: Groves had, with the insistence of the British, allowed a number of French scientists to join the project. (He compartmentalized them in Canada and didn’t give them access to US data, but still.) When the war in Europe ended the Nazis had been pushed out of France,1 they wanted to return to Paris and to see their old boss, Frédéric Joliot-Curie, who was by then a known Communist. Groves was pretty uncomfortable with this and it created quite a diplomatic row between the US and the UK;2 it was thus in Chadwick’s interests to simplify the situation by removing all non-Brits from the British delegation, which included Rotblat (who was, again, still a Polish citizen).

In any case, Brown points out, Rotblat didn’t totally get out of the nuclear business for a number of years; he continued to teach nuclear physics to people whom he knew would be working on the UK atomic program for a number of years after the war ended, before he started his real, devoted  activism.

None of this diminishes Rotblat’s work or his obvious deep ethical convictions — he was clearly deeply opposed to war and worked tirelessly on disarmament issues for most of his life — but it does make a too-perfect story seem a bit more realistic. (Stan Norris was there, and asked whether Brown believed that Groves really did, as Rotblat claimed, announce that he had always thought the USSR was the key target. Brown thought it not implausible. I don’t find it too implausible, myself, given that it would have been pretty natural for the US to be looking to the USSR as its “natural” enemy after the war was ending, but it does have an element of being “too perfect” to it.)

General Groves (left) and David Lilienthal (right) share a moment. I imagine that most of their interactions looked like this, private or public. Photo by Ed Westcott.

My other busy-ness has been pulling together a presentation I’m giving at the Policy History Conference in Richmond, Virginia, on Thursday, relating to the early classification policies (and the failure of classification reform) during the David Lilienthal years at the U.S. Atomic Energy Commission (AEC), 1947-1950. I don’t want to go into details on here, but the paper is basically about the fact that numerous times in the first (and most ambitious) years of the AEC, the technocratic liberals who were running it attempted to re-think and re-work US nuclear classification policy from the ground up. It didn’t work, for a variety of reasons, the most damning of these being the series of shocks of late 1949 and early 1950 (Joe-1, the H-bomb debate, Klaus Fuchs).

The document I want to share this week is somewhat tangentially related to both of these issues. It is a letter from General Leslie Groves to David Lilienthal from November 1946, which was just on the cusp of the Manhattan Project’s transfer of all atomic responsibilities to the newly-created Atomic Energy Commission.3

Click image to view full PDF.

It’s a short letter; so here’s the transcription:

Dear Mr. Lilienthal:

I desire to bring to your attention that in the past I have considered it in the best interests of the United States to clear certain individuals for work on the Manhattan Project despite evidence indicating considerable doubt as to their character, associations, and absolute loyalty.

Such individuals are generally persons whose particular scientific or technical knowledge was vital to the accomplishment of the Manhattan Project mission. In some instances, lack of time prevented our completely investigating certain persons prior to their working for the Manhattan Project; so that in some cases individuals, on whom it was subsequently determined that derogatory information existed, had access to Project information.

With the appointment of the Commission and the legal provisions for investigation of personnel by the Federal Bureau of Investigation, I see no reason why those people on whom derogatory information exists cannot be eliminated. I unhesitatingly recommend that you give the most careful consideration to this problem.

The FBI is cognizant of all individuals now employed on the Manhattan Project on whom derogatory information exists.

Sincerely yours,
(signed)
L.R. Groves
Major General, U.S.A.

Quite a curious sort of thing to send and receive. Imagine being in Lilienthal’s position: here’s General Groves, handing off the bomb project to you, saying, “by the way, I hired a bunch of people who I now want to tell you might not be loyal. You might want to get rid of them. Anyway, I completely agree you should think about this pickle you’re now in. Good luck!”

Who were these “doubts”? Probably people like Leo Szilard, Frank Oppenheimer, and Philip Morrison. It may even have included Arthur Compton, who was always “on the line” for the security people (Compton wasn’t very discreet and signed too many petitions).  It probably would have included Joseph Rotblat if he was still on the project (but as we know, he left). It did not, apparently, include J. Robert Oppenheimer, though the letter did re-surface at his security hearing.

Lilienthal wrote back to Groves noting that since Groves had kept a lot of these people on well beyond Hiroshima and Nagasaki, that Groves apparently did not regard them as “a source of critical hazard.” Groves then wrote back to Lilienthal saying that actually they couldn’t just be fired and removal was a slow process, so their presence didn’t imply anything about how non-hazardous they were.4

What’s going on here, plainly, is an elaborate game of CYA — Groves is trying to imply that if these “doubts” became a problem, they were passed off to the AEC and shouldn’t hang on his head. Lilienthal, shrewdly, tries to turn it around to make sure that they do, in fact, hang on Groves’ head — he isn’t willing to just take all of the responsibility here if they are kept on, and he doesn’t also just want to do whatever Groves is implying he ought to do. Groves, in turn, was trying to deflect some of that themselves. They’re creating a paper trail — one that was, indeed, later followed up.5

I find this sort of bureaucratic activity fascinating. It’s not the sort of thing that gets into the grand narratives of history — either the Groves-Lilienthal exchange, or the diplomatic flareup that (apparently) led to Rotblat leaving the Manhattan Project. It’s this sort of thing that gets washed away by straightforward, coherent narratives, replaced with stories of high ethics and morality, when so much of what went on from day-to-day was much more down to Earth in its considerations. This is one of the reasons I prefer working with archival materials more than secondary sources, personally; not because I don’t trust the scholarship (I generally do) or that I don’t get something out of it (ditto), but because I never feel I really understand what’s going on until I’ve gone through all of the bureaucratic and minor miscellany myself, unearthing the mundane.

  1. I hadn’t checked my dates before writing this; the “French problem” surfaced in December 1944, when the war in Europe was still going on, but the Nazis were no longer occupying France. Rotblat left the project that December as well, for England. [↩]
  2. I discuss this “French Problem,” as it was called at the time, in my “Patenting the Bomb” article, because a large part of the dispute centered around promises the British had made the French regarding early French patents on nuclear reactors and bombs. [↩]
  3. Citation: Leslie R. Groves to David E. Lilienthal (14 November 1946), Records of the Atomic Energy Commission, RG 326, National Archives and Records Administration, College Park, Maryland, Office of Secretary, General Correspondence 1946-1951, Box 11, “Security Clearance of Personnel, Volume 1.” [↩]
  4. The back-and-forth is contained in the Oppenheimer security hearing, page 169. [↩]
  5. When asked about this in the Oppenheimer hearing, Groves was pretty straightforward about it:

    If I put it in writing, that they would always be thinking about the record. That is the reason that the letter was written. I have never made a practice of trying to protect myself on the record, but I thought this was one time that I could secure action, and it was not written really with the idea of clearing my skirts for something that might come up, such as this, many years hence. It was to make him do it whether he wanted to do it or not.

    It’s also clear that this was born out of the difficult relationship between Groves and Lilienthal. “Mr. Lilienthal had made it very plain that he wanted no advice of any kind from me. He wanted nothing whatsoever to do with me. He thought that I was the lowest kind of human being, and he was not going to get anything from me.” Oppenheimer hearings, page 169. [↩]

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Visions

Elusive Centrifuges

by Alex Wellerstein, published June 1st, 2012

To round off this week of centrifuges, I thought we might actually look at a few of them. Photographs of real-life enrichment technologies are not too common. You can find quite a number of pictures floating around of Calutron (electromagnetic enrichment) technology from World War II, but that’s because the United States decided pretty early on that Calutrons weren’t too sensitive. (Rightly or wrongly; just because they are inefficient doesn’t mean they don’t work. Iraq famously pursued Calutron technology during its pre-1991 nuclear program; the major technical snag seemed to be that somebody bombed the facilities.)

But gaseous diffusion? Laser enrichment? Aerodynamic enrichment? Not so much, beyond photographs of BIG buildings or very schematic conceptual diagrams. With centrifuges, though, there are some images from a variety of time periods and sources. As I mentioned on Monday, you can find some pretty nifty Zippe-type centrifuge photographs in old research reports from the 1950s that the Department of Energy still hosts pretty accessibly. These are kind of amazing, given how they more or less disassemble the devices in what looks like a pretty helpful fashion.

“Scoop assembly for handling gas inside the rotor and parts of rotor.” (1959)

“Molecular pump and rotor.” (1959)

…and so on with the “powdered magnetic core, completed stator, and driven end of rotor showing steel plate and supporting needle,” and “upper magnetic bearing, rotor, and top of scoop assembly,” and even a nice little one of the rotors mounted up for stress testing. Interesting that these things are out there — especially when the CIA apparently decided, in 2003, that showing rotors of pre-1991 Iraqi centrifuges was too sensitive to put up on the web (after they had already put them up for awhile).

There are a few photos of URENCO centrifuge plants from Europe, but not as many as you’d think from a venture whose corporate slogan is “enriching the future.” I’m partial to this gold-tinted one that’s been floating around the web for awhile; it looks like Scrooge McDuck was the contractor (but I’m pretty sure it’s just the lighting — other images I’ve seen show them to be silvery):

It’s hard to get a sense of scale from cascade photos like this, though.

In the early 1980s, the United States’ DOE built a prototype centrifuge plant at Piketon, Ohio, but abandoned it by 1985. Much more recently (the 2000s) the private United States Enrichment Corporation took over the site and has been building a demonstration plant on it. What’s interesting about these centrifuges is that they are of a different model than the previous ones; the “American centrifuge” is a colossally large design. (The fact that they have to label them as “American” is a nice reflection of the fact mentioned on Monday that the US lost its initiative in developing centrifuges. We don’t have the “American” gaseous diffusion method or the “American” electromagnetic method.)

The 1980s Piketon photos are pretty impressive. These are from the DOE Digital Archive:

The last one really gives you the sense of scale with those suckers — they are huge!

The current Piketon plant looks pretty similar. USEC has a few photos on their own website:

I find these less inspiring, photographically, than the ones from the 1980s, but they look like the same centrifuges. The length here — some 12 meters long — is functional, and not just an example of the Supersize-Me American culture.  The “American centrifuge” is much more efficient than the other models currently being used, apparently.

Now, all of the above is sort of interesting, but is just something of a prelude for the next batch of photos. In April 2008, Iranian President Mahmoud Ahmadinejad made an official visit to the Natanz site, one of Iran’s controversial centrifuge facilities. Surprisingly, his office took several dozen photos of the visit and posted them on the official Presidential website. These have been a goldmine for wonky types wanting to understand Iran’s centrifuge developments, and have, of course, served as the illustrations for half a million articles about Iran and the bomb since then. A few of my favorites:

The last one I like because of a small, easy-to-miss detail: you can see one of the blue IAEA safeguard cameras above Ahmadinejad’s head. The blue box is a sealed case inside which the video camera is locked, and the closed-circuit camera feed is beamed back to IAEA headquarters in real-time (so I gather). (A correspondent e-mailed to say that at the plant in question, a pilot plant, the cameras aren’t real-time — they just stored the footage for the IAEA to pick up, which is every other week or so. I thought I had heard somewhere that they were real-time, but I can’t remember where. They do have real-time monitoring in their plants that can do up to 20% enrichment, though.)

Given how relatively few photos there are of centrifuges floating around, why did Iran post so many on its Presidential website? I think the message is pretty clear, personally: they are trying to demonstrate a lack of anything to hide. If the centrifuge program isn’t “secret,” then it isn’t scary, right?

Of course, the obvious rejoinder to this is that they are of course being selective about what they show. Such is the nature of any kind of publicity like this. You show a little, to show that you aren’t secretive, but of course, you do hold things back. Whether that holding back violates the NPT or the Additional Protocol and so forth is a question for another day. But I’m always fascinated by the theatre of “transparency,” which has — since the early days of the bomb — been part of maintaining nuclear secrecy. Secrecy has never just been about holding things back: it has always been a game of simultaneously withholding and releasing, of giving a little so you can hold back a lot.

How do we distinguish between genuine transparency and transparency in the name of secrecy? That’s the $64,000 question, isn’t it? Because when you get it wrong, you get a situation like Iraq: trying to prove a negative (that they didn’t have active WMD programs hidden away) turned out to be an impossible job (not because it is inherently impossible, but because of the various political and organizational forces stacked against the attempt). One can distinguish between the two in retrospect — once you’ve actually dismantled the country and its programs and whatnot — but that’s disturbingly too late.

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Redactions

The Centrifuge Conundrum (1964/1968)

by Alex Wellerstein, published May 30th, 2012

On Monday I wrote a bit about the history of the Zippe-type gas centrifuge. What’s fascinating about the Zippe centrifuges, for me, is that they were pushed internationally for the purpose of commercialization, and because of their origin outside of the United States (and their post-Atoms for Peace publicity), they were not put under as heavy restrictions as other uranium enrichment technologies — despite the fact that they are really the ideal enrichment method for a potential new proliferator. This created a major problem for the United States. Centrifuge technology was both hard for the US to meaningfully control (since it didn’t originate in secret American labs), and US companies were eager to “stay competitive” with Europe in the vast new frontier of enrichment possibilities they opened up (which seemed like big money in the 1960s, when the future of nuclear power was still rosy). For this week’s document(s), I want to share two different (short) positions on what we might call the “centrifuge problem” of the 1960s.

Glenn Seaborg (left) and Robert McNamara (right) flank President Kennedy as he visits the Lawrence Berkeley Laboratory in 1962

The first is a 1964 memo from Robert S. McNamara, then the Secretary of Defense, to Glenn T. Seaborg, then the Chairman of the Atomic Energy Commission. It comes at a time — about six months prior to the first Chinese nuclear test — where the United States started to get really serious about proliferation, or as it was often called then, the “Nth country problem.”1

Click image for the PDF

McNamara’s memo aimed to confront the problem of centrifuge proliferation head-on. Proliferation was a problem in McNamara’s eyes because, “...the acquisition of fissionable material for even one or two weapons by a non-nuclear country could have a destabilizing impact on international relations which would be harmful to US security.” (This is, of course, exactly why helping other countries proliferate might seem like a good idea to some countries, as Matthew Kroenig has argued in his fairly recent book, Exporting the Bomb.)

But McNamara knew he couldn’t end proliferation through simple technical means: “I recognize that the controls which can be placed on technology can only retard, not prevent, its growth and diffusion. Even so the goal of retardation is a worthwhile one.” This is actually a very old argument related to the benefits of secrecy: it doesn’t stop diffusion of information, but it does slow it down. And slowing it down can be strategically valuable.

Supporting this “retardation” goal (a somewhat unfortunate choice of words), McNamara wanted to slow down the diffusion of centrifuge information. His methods:

  1. “…dampen the incentive of countries capable of developing their own gas centrifuge technology.” That is, guarantee nuclear fuel to countries so they are dependent on the US for enrichment and don’t feel they need to develop their own enrichment capabilities. He also thinks that the US should support safeguards on natural uranium — which is interesting since as far as I know, unenriched, natural uranium is not safeguarded today.
  2. “…inhibit assistance to less developed countries.” Specifically he means keeping classification and export controls up in the US program, since that will make nuclear newbies have a harder time.
  3. “…support US gas centrifuge technology at a high level so that the US can stay abreast, or ahead, of developments in other countries.” This is a very good task to send to the Chairman of the AEC: full steam ahead with centrifuge development! But keep it secret. McNamara is no doubt aware that half of the problem here is that the US hadn’t kept abreast, or ahead, of centrifuge developments in other countries (see my previous post on this).

Lastly, Seaborg had asked McNamara if there were any US security objectives that non-proliferation policy might interfere with. (An interesting question.) McNamara says no — the only issue hinted at is the basing of nuclear weapons in NATO countries (“nuclear sharing”), but McNamara seems pretty confident that he doesn’t consider that to be proliferation since it is not a creation of an “independent” nuclear state. (This was a major sticking point for the NPT negotiations in the late 1960s; the USSR was desperately afraid of giving the West German “revanchists” control of nuclear weapons and tried to use the NPT as a way of opposing nuclear sharing policies.)

Now let’s go to the other document, an extract from Seaborg’s office diary from 1968. Seaborg’s office diary entries are generally speaking quite short and not usually very revealing, but this one is interesting. It concerns his day on Monday, November 11, 1968. Here’s the first relevant section:2

At 10 a.m. I presided over [Atomic Energy] Commission Meeting 2352 (action summary attached) [not attached]. At the Commission Meeting we discussed the possibility of modifying our policy of secrecy on our gaseous diffusion and gas centrifuge methods for enriching U-235. The Europeans and Japanese are developing these methods and our policy seems to be outmoded if we want to influence them and stay abreast of them. Despite objections from [Commissioner James T.] Ramey, who prefers the status quo, we asked the staff to make a study, with the aim of coming up with various plans to make it possible to cooperate with the Europeans and Japanese in this area.

So this is an interesting counter to the McNamara concern. The Europeans and Japanese were pushing ahead in both centrifuge and diffusion technology, and there was a question as to whether the AEC should loosen their restrictions in order to “influence them and stay abreast of them.” At least one AEC Commissioner wanted to take a conservative approach, but Seaborg and the others were interested enough in the possibility to order up a staff study, which was often the first step towards a policy change.

There is one more relevant part of that day’s diary entry; that evening, Seaborg went to see the German delegation to a nuclear industry conference. Here’s what he wrote:

Dr. Michael Higatsberger (of Austria) told me the AEC briefings at Oak Ridge last Thursday and Friday on our nuclear fuel policy were very successful and may have convinced many Europeans that they shouldn’t build an enriching facility soon. Charles Robbins (AIF) told me about industry feeling that AEC suppression of industrial work on gas centrifuge is counter to American method of doing business.

Another interesting paring — an Austrian saying that the US had probably convinced the Europeans not to create in their own collective enrichment facility, and an American nuclear industry representative (the AIF was the Atomic Industrial Forum, a nuclear lobby group) saying that AEC control over centrifuge work is “counter to [the] American method of doing business.” (The UK, Netherlands, and Germany did create URENCO in 1971, so not all of them were apparently convinced. URENCO uses gas centrifuges for its enrichment, and is where A.Q. Khan got access to the centrifuge technology that he later took back to Pakistan and exported to quite a few other places.)

What I like about these two documents is they paint a picture of the various political, technical, and economic forces pulling in different directions on the centrifuge problem. Gas centrifuges, like all enrichment technology, have been duel-use since birth, but the fact that they developed outside of US auspices made them especially difficult to control. This difficulty then presented the problem of whether one ought to try and control them, and if so, how. Heavy controls might slow things down, but it also could easily encourage others to press ahead with independent development. Loosening restrictions might increase diffusion, but could also increase dependence on US assistance.

  1. Citation: Robert S. McNamara to Glenn T. Seaborg (23 May 1964), copy in Nuclear Testing Archive, Las Vegas, NV, document NV0903211. [↩]
  2. Glenn T. Seaborg, Office Diary entry (11 November 1968), copy in Nuclear Testing Archive, Las Vegas, NV, document NV0910540. [↩]

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Meditations

Zippe’s Centrifuges

by Alex Wellerstein, published May 28th, 2012

R. Scott Kemp, a friend of mine at Princeton’s Science and Global Security program, has just informed me that the latest issue of Technology and Culture has come out with his new article: “The End of Manhattan: How the Gas Centrifuge Changed the Quest for Nuclear Weapons.”1

It’s a good read and I highly recommend tracking down a copy if you are interested in nuclear history, but especially if you’re interested in the history of proliferation. Scott’s article is the best account I’ve read about how the gas centrifuge went from being a more-or-less abandoned approach to uranium enrichment during World War II to being the proliferation concern of the late-20th and early-21st centuries.

Major components of a Zippe centrifuge, 1959

Gas centrifuges had been one of the many types of enrichment technology pursued during the Manhattan Project. Early on, they were heavily favored over the more technically daunting electromagnetic and the totally-untried gaseous diffusion method. Jesse W. Beams at the University of Virginia was the country’s centrifuge expert and he had been looking into using them for isotopic separation as early as 1940. As a result, all of the Manhattan Project centrifuge work was concentrated with him at his laboratory, and in 1941, nearly four times more was allocated to the centrifuge project as was the more speculative gaseous diffusion method.

This is an interesting point to note — we give the Manhattan Project management a lot of credit for trying everything. They spent far more money than a more “optimized” project might have, because they investigated a lot of things that didn’t work out. But despite this approach, they still centralized the work being done on any specific method, usually within a single laboratory, often under the direction of a single scientific luminiary. So Ernest Lawrence was the don of the electromagnetic method; Arthur Compton oversaw reactor research; Harold Urey ran diffusion; and so on. Which seems like a great idea on the face of it. But what if the person you chose just didn’t take the research in the right directions? What if, within that short timescale, they just didn’t hit upon the right answer?

Such was the case with Beams, in Kemp’s assessment: Beams just didn’t figure out how to get centrifuges to work sufficiently well enough. As a result, the Manhattan Project folks proclaimed centrifuges a dead end and dropped the approach in 1944. After the war, there was little US interest in centrifuges — it didn’t seem like they were very workable, certainly not compared to gaseous diffusion. And since gaseous diffusion worked fine for them, they didn’t look too far afield. The lesson of the war, as the US saw it, was that centrifuges weren’t worth the effort.

Schematic of Zippe’s short bowl “ultracentrifuge,” 1958

But in Europe and the USSR, though, work on centrifuges continued. Scott’s account goes into this in some wonderfully wonky technical detail. The end result is that Gernot Zippe, an Austrian physicist, who in the early 1950s figured out (with others) how to fix the problems that Beams had with his centrifuges. Amazingly, he did this while being a prisoner of war in the Soviet Union.

The Zippe centrifuges weren’t anything magical. There was no “secret,” per se, and they didn’t involved any special materials. They just involved working out a few engineering details that made the devices reliable and stable. The major new features introduced by another Austrian POW, Max Steenbeck, and implemented by Zippe were:

  1. “a ‘point’ bearing that allowed the centrifuge rotor to spin on the tip of a needle (like a toy top) with almost no friction.”
  2. “the application of loose bearings and weak damping, which allowed the centrifuge to adjust itself so that it spun quietly on its center-of-mass axis without vibration instead of trying to force the axis of rotation”
  3. “to drive the rotation using electromagnetic fields, just as the armature of an electric motor drives its internal rotating shaft”

That’s it. In engineering terms, these are clever, but hardly revolutionary. These three relatively simply engineering changes “solved essentially all the mechanical problems that had plagued Manhattan Project centrifuges,” Scott writes. In fact, he argues:

It wasn’t that the centrifuge wasn’t possible in the World War II period — it’s just that Beams never figured it out. Scott notes:

The flawed centrifuge was made viable by the application of engineering solutions that were mostly invented around the turn of the twentieth century and all of which predated the Manhattan Project—evidence that the latter’s centrifuge program was frustrated not by the limitations of manufacturing or the technology of the day, but rather by a preliminary design that was never developed to its fullest possible extent.

So the gas centrifuge was really completely viable as early as World War II, but the Manhattan Project scientists just couldn’t get it to work. I thought that was a pretty bold conclusion, one that goes in the face of the standard “superiority myth” that pervades the Manhattan Project work.

Things get really interesting, though, after Zippe et al. figure out how to make it work. Zippe and his colleagues actually convinced the Soviets to let him out early (and to pay him!) if he helped them commercialize centrifuges in Europe. (I think we can file this under “cool things that can happen once Stalin buys the farm.”) Zippe and his colleagues were released from the USSR in 1956, and he went to East Germany. From there, though, he made his way west, and became a centrifuge evangelical — he wanted to commercialize them.

He went around Europe and the United States showing folks how to make efficient gas centrifuges. In 1958 and 1959 he spent time at the University of Virginia (Beams’ home turf) showing them how it was done. Amazingly, this work seems to have been unclassified — you can find the progress reports, featuring the diagrams and photographs I’ve used in his article, on the Department of Energy’s Information Bridge.2

In 1960, the US realized that the centrifuge was actually going to be a proliferation issue, and started trying to classify the technology again. The problem was, of course, that all of the key developments were produced by non-Americans not in the United States. So in effect the US was saying that nobody in the United States was going to be allowed to work on this without a security clearance, while scientists in Europe could pursue it with a freer hand.

The result of all of this Atoms-for-Peace (Atoms-for-Cash?) enthusiasm with regards to gas centrifuges is that the technology is pretty well dispersed.  Scott concludes that:

Today, at least twenty countries have built or acquired centrifuge technology, and the history lesson drawn here suggests that it is within the capability of nearly any state to do so.

As Scott (and Alex Glaser and Houston Wood) have argued elsewhere in another great article,3 all of this should put to rest any idea that technical solutions alone can limit future nuclear proliferation — we live in a definitely post-Manhattan Project world, and this stuff just isn’t rocket science anymore.

  1. R. Scott Kemp, “The End of Manhattan: How the Gas Centrifuge Changed the Quest for Nuclear Weapons,” Technology and Culture 53, no. 2 (June 2012), 272-305. [↩]
  2. The photograph of the centrifuge is from Gernot Zippe, “A Progress Report: The Development of Short Bowl Ultracentrifuges,” UVA/ORL-2400-59 (1 July 1959); the diagram is from Gernot Zippe, J.W. Beams, and A.R. Kuhlthau, “The Development of Short Bowl Ultracentrifuges,” UVA/ORL-2400-58. Scott’s article brought both of these reports to my awareness. [↩]
  3. Houston G. Wood, Alexander Glaser, and R. Scott Kemp, “The gas centrifuge and nuclear weapons proliferation,” Physics Today 61, no. 9 (September 2008), 40-45. [↩]

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Visions

James Conant’s Atomic Bomb Sketch? (1943)

by Alex Wellerstein, published May 25th, 2012

I had fun with the little visual mystery I posted last Friday, so here’s another one I’ve been chewing over for awhile.

Drawings of “official” atomic bomb designs are rare. (Where “official” means “created by people who actually build bombs.”) It’s the sort of thing which is generally kept close — what are released are generally extremely sanitized abstractions, which are then elaborated upon by people without security clearances (like John Coster-Mullen).

So I was somewhat surprised to find, buried in some files of the Office of Scientific Research and Development, this drawing which appears to have been made by none other than James B. Conant, then the President of Harvard University:

That looks an awful lot like the drawing of a gun-type nuclear weapon. But is it?

Conant, of course, was a major scientific administrator during the war. He was a chemist by training, and was no stranger to secret projects: during World War I, he had worked to develop lewisite for use in Europe while working at the “Mousetrap” facility in Cleveland, so called because once you went in, you were never supposed to come out.1 The chemical munitions that Conant worked on were never used in the war; the armistice came just before they were to be shipped out. During World War II, Conant was pals and colleagues with Vannevar Bush, head of the OSRD, and the two of them did quite a lot of work on early atomic development policy.

The context of the sketch is apparently a note from Conant to Bush, dated January 21, 1943 (with notes that it was amended March 10, 1943).  I say “apparently” because, while this follows the other sequentially in the file, it isn’t clear that they are attached or from the same period. (The handwriting is Conant’s though, which is something. Don’t read too much into the fact that the pages look different; one is just scanned in black and white, the other as grayscale.)2

The note itself is pretty hard to decode; it is in Conant’s nearly-impossible handwriting. The basic gist of it is that he is estimating how much enriched uranium they can product at Oak Ridge and what that implies about when a bomb would be ready (he seems to think one would ready by September 1944, and then later updates the note to push it back a bit).3

On the “drawing” page itself, there is a list (anything in italics is written by me, trying to make sense of his handwriting):

(1) Metallurgy
(2) cows [!?! see below]
(3) Development of technique for handling material in bulk
.                                          70-80, 90% of critical
(4) What cases are effective? [could this mean casings?]
(5) Further [???] [???] for cross section
(6) No. of neutrons for 49
(7) Capture + emission[?]  of neutr.                          (Bohr)
(8) Cross section of scattering[?]
(9) Firing problem
.                              length of time first mass stays in
(10) Source of neutrons Neutron source
(11) Effect of dilution
(12) Protection against thermal neutrons                (25)

To my eye, even with the ambiguity caused by his bad handwriting, it looks like a list of problems to tackle when thinking about designing a bomb the first time. What will the metallurgy of U-235 or plutonium be like? How will you shape these materials safely on a lathe? Was sorts of casings or reflectors will be best? How do you handle this stuff without getting totally irradiated? How many neutrons will plutonium emit per fission? How will you make a neutron initiator? What’s the engineering of the actual bomb assembly going to look like? And so on.

Except, of course, for “cows,” which I find inexplicable. It’s not a codename I’m familiar with. I am almost surely transcribing it wrong, but it looks a lot like “cows”:

Cows. Hmm. There were some cows involved in the Manhattan Project in a peripheral way, but I doubt he was thinking about that at this point. More likely is I’m making a garble of his handwriting again, but now that I’ve seen “cows,” I can’t stop seeing it. (Got a better guess? Let me know.)

Anyway, what it looks like to me is the result of either brainstorming or notes from a meeting that Conant was having, all of which seems to pertain to weapon design issues. So the idea that he might have sketched a crude gun-type design at the bottom of it isn’t fanciful in and of itself.

The drawing seems to show one “40 lb” piece of fissile material at the bottom of a gun barrel, with the cross section of a ring of the same stuff at the other end of it inside some sort of heavy neutron reflector or tamper. There are some other numbers nearby; it seems to say “10 meters, 30 ft.” Is that meant to be the length of the gun barrel? It would be pretty long, much longer than any of the actual bombs estimated for combat, but it might just be a back-of-the-envelope guess.

The bomb — if it is a bomb — that Conant has sketched out here doesn’t look much like Little Boy actually looked, but it doesn’t look wildly different than Thin Man, the plutonium gun-type bomb that was pursued before Little Boy.

Experimental bomb casings from the aborted “Thin Man” plutonium gun design. There are early “Fat Man” casings designs in the background.

The actual Little Boy weapon used (according to John Coster-Mullen) a cylindrical projectile that weighed around 85 lbs, and the “spike” that it was shot into (not the other way around) weighed 56 lbs, bringing it to a total of 141 lbs of fissile material, considerably more than is shown in this sketch. But still, the entire point of the list seems to be that they don’t know the details at that point.

The other possibility is that this isn’t a bomb at all, and that it is some kind of “tickling the dragon’s tail” criticality experiment. But that’s a much more boring conclusion.

Instead of pointing out how crude and inaccurate the drawing is, though, I’m still just amazed that it was hiding on that microfilm, waiting to be stumbled upon. It’s oh so rare to see bomb designs in “the wild,” and this one is considerably more “real” (in the sense of it being less conceptual and more of an engineering-style layout) that the only other declassified drawings from the same period I have seen (those in the Los Alamos Primer).

Did Harvard’s President sketch an atomic bomb on his notepad? I don’t know, but it’s a very real possibility, is it not? I wonder if any Harvard president since then — much less Harvard’s current President — has ever done such a thing.

  1. See James Hershberg’s James B. Conant: Harvard to Hiroshima and the Making of the Nuclear Age (New York: Knopf, 1993), chapter 3. [↩]
  2. Citation: James B. Conant to Vannevar Bush (21 January 1943, amended 10 March 1943), Bush-Conant File Relating the Development of the Atomic Bomb, 1940-1945, Records of the Office of Scientific Research and Development, RG 227, microfilm publication M1392, National Archives and Records Administration, Washington, D.C., n.d. (ca. 1990), Roll 4, Target 3, Folder 21, “Miscellaneous Bush-Conant Material, May 1941-October 1944.” [↩]
  3. Here’s an attempt by me to decode Conant’s handwriting. Anything I’ve put in italic means “I can’t read this.”

    Memo to V. Bush               Amended by JBC before [???] on March 10, 1945
    From J.B. Conant              Date Jan. 21, 1943

    The latest news from the electromagnetic front via Gen. Groves is (1) Tennessee Eastman are quite confident that process can be made to work. It now seems quite certain that each tank will yield from 50-300 mg per day.
    At  500 tanks that means 50-150 g per day.
    If priorities can be settled there is a chance this output can begin November 1, 1943 (First set Y tanks Aug 1). [Inserted note:  I ??? this now, March 10, 1943; a bomb will require 24 ???; 100 g a day begins ???, 1944. Will take till ??? 1, 1944 for amount! There is still a chance for a military effort in 44.]  This would yield first first [sic??] bomb Feb 1, 1944, at rate of 100 gm per day. This might mean first mean first military result July 1, 1944 allowing four months for developing bomb and manufacturing material for a second. I still believe barring miracles, best day is Sept 1, 1944 . The Chicago method might come along at the same point. So we have two chances of making that schedule. J.B.C.

    That’s not the world’s best transcription attempt (I loathe Conant’s handwriting, I should probably say), but you can get the gist of it, I think. “The Chicago method” refers to plutonium production. “Y” tanks refer to the electromagnetic method used at Y-12 in Oak Ridge. I’m open to any guesses as to better transcription attempts. Conant’s estimate for when they’d have a bomb ready was off by about six months, something I’m sure my German friends are undoubtedly thankful… [↩]

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