Posts Tagged ‘Proliferation’


The Centrifuge Conundrum (1964/1968)

Wednesday, 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. " 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. []

Zippe’s Centrifuges

Monday, 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. []

Re-examining the The Nth Country Experiment (1967)

Wednesday, January 4th, 2012

This week's document is one that most nuclear wonks have seen before: the Summary Report of the Nth Country Experiment, produced by the Lawrence Livermore laboratory in 1967. It made a big splash when it was declassified in 2003, for good reason. Here was an official government study, from over 30 years ago, which said that there were essentially no secrets left when it came to designing nuclear weapons.1

Click image for full PDF.

The report summarizes the results of a 1964 "experiment," in which Livermore hired two physics postdocs and had them try to come up with "a credible weapon design" based only on information in the public domain and computer support. A third postdoc was added a year later. The experiment ended in April 1967.

From a modern perspective, this is fascinating stuff. If three postdocs can design a nuclear weapon, then what's to stop a terrorist? What's the value of secrecy? Isn't it amazing they were worried about this stuff almost 50 years ago?

But I think there are some more things to say about this.

Read the full post »

  1. Source: W.J. Frank, ed., "Summary Report of the Nth Country Experiment," UCRL-50249 (March 1967), via the National Security Archive. []