Foreign Policy Blogs

The Shoddy Science of AP’s Iran Diagram

On November 27 the Associated Press published a diagram it received from officials, “of a country critical of Iran’s atomic program.” It allegedly calculates the explosive force of a nuclear weapon, which the sources have labelled, “a key step in developing such arms.” It has been touted as proof of Iran’s nuclear aims and purportedly a willingness to develop a bomb with triple the explosive force of Little Boy, which the United States dropped on Hiroshima.

While troubling, there are some doubts regarding the authenticity and the ramifications of the leaked document. The subsequent day after the publishing of the Associated Press diagram, Dr. Yousaf Butt and Dr. Ferenc Dalnoki-Veress penned DIY Graphic Design for the distinguished Bulletin of the Atomic Scientists. In this article the authors’ viewpoint is aptly summed up within its highlight text, “The diagram leaked to the Associated Press this week is nothing more than either shoddy sources or shoddy science. In either case, the world can keep calm and carry on.” Both authors show that the diagram could easily have been created by someone with limited knowledge of nuclear physics and further damaging to the report, that the diagram in question includes a major mistake that would not have been made by scientist performing their duties at the national level. Overall, even the supposed creation of the diagram by Iranian nuclear scientists would not point to the imminent or ongoing development of a weapons program by the Islamic Republic.

The Foreign Policy Association’s Alexander Corbeil sat down with Dr. Yousaf Butt to discuss the article and to gain insight into why the West and Israel should not treat the diagram with alarm. Dr. Butt is a nuclear physicist and currently a research professor and scientist-in-residence at the Monterey Institute of International Studies. He was formerly a Scientific Consultant to the Federation of American Scientists and a physicist in the High Energy Astrophysics Division at the Harvard-Smithsonian Center for Astrophysics. He holds a Ph.D in nuclear physics from Yale University and undergraduate degrees from the Massachusetts Institute of Technology.


1.       Let’s begin with the question that has been on the mind of every observer since this diagram has been published, even those who have read your dismissal of the Associated Press report. If from Iran, does the diagram, at minimum, show that the Islamic Republic is contemplating the creation of a nuclear weapon in the near future?

No. Even if it is authenticated as being of Iranian origin, there is very little one can conclude from such a diagram. Frankly, besides the word of the anonymous sources leaking it, we don’t even know whether it necessarily relates to nuclear issues at all: such curves could correspond to many natural phenomena. In fact, the shape of the curves in the diagram does not correspond to a typical nuclear explosion, quite apart from the other major mathematical error we found with it. Now, let’s give the folks who leaked it the benefit of the doubt and pretend it is related to nuclear matters: as my colleague Dr. Ferenc Dalnoki-Veress and I noted in the Bulletin piece, such a graph could well be the work of an advanced undergraduate or graduate-level student enrolled in a nuclear physics course. Even if it is the work of an Iranian scientist – which would surprise me given how shoddy it is – we don’t know if the scientist was doing something, for instance, for a class presentation, or maybe pitching an idea he had to his colleagues. There is no restriction on people doing calculations in sovereign nations. So, no, there is no indication that the graph, even if authenticated, even if it relates to nuclear matters, and even if it came from an Iranian nuclear scientist represents or represented the official view or intentions of the government of Iran.

 2.       You point out that other non-nuclear states, which have ratified the Non-Proliferation Treaty, have conducted more serious computational research on nuclear weapons, citing calculations by a military institution in Brazil. If these countries do not have nuclear weapons ambitions, why go forward with the calculations? Does the answer to this question shed light on the reasons behind Iran’s supposed nuclear program and the AP diagram?

That’s correct. Well, it was more than a few calculations. This was years-long computational research directly relevant to nuclear weapon design – specifically, the American W-87 thermonuclear warhead – and, yes, it was carried out at a military institute in Brazil and published as a doctoral thesis in 2009. While this raises eyebrows, and should rightly be a concern, it is unfortunately  still not a clear legal breach of the “Comprehensive Safeguards Agreement” or “CSA”, in the lingo, between Brazil and the IAEA. It is important to understand that verifying signatory nation’s obligations under the NPT is carried out via these agreements, and that they deal with the accountancy of nuclear materials very specifically and narrowly. They do not permit the IAEA to launch a wild goose chase within signatory nations. So just as the Brazilian PhD thesis research into the American thermonuclear warhead did not qualify for a formal violation, similarly the Iranian graph — even if it isn’t a hoax – wouldn’t violate the Iran-IAEA CSA, since no nuclear materials are involved.  It’s just a study. Now, to get to the heart of your question, there are many reasons that universities and institutes may do such studies. First off, not all such studies need to be commissioned or blessed by or even known by the national authorities, and they can be of varying fidelity or sophistication. A university professor may, of his own initiative look into such things out of pure interest or assign it to a graduate student as theoretical exercise. Admittedly, the physics are fascinating!  Now, if it’s being done at a national or military institute, the government may be interested making sure that some of the nation’s scientists are versed in the relevant physics should the country decide to weaponize in the future. Basically, it may be a kind of hedging strategy: preserving the option to weaponize in the future should they decide to do so.  But, fundamentally, nuclear science is a dual-use science: once you learn the physics of a nuclear reactor you pretty much know the physics of a nuclear bomb. But the mere existence of a theoretical study does not imply the parallel existence of an actual weapons program.

Now coming back to that Brazilian study; the main take-away is the contrast in how different Brazil is being treated from Iran even though the Brazilian study is far more sophisticated. What this really speaks to is the inconsistent application of non-proliferation laws: there have long been complaints that there are double standards in how these laws are applied and if the situation is not corrected soon it may well lead to the demise of the non-proliferation regime. For instance, although Iran, Egypt, South Korea, and Libya were all found non-compliant with their IAEA safeguards agreements in the past, only Iran was referred to the UN Security Council. Why? And do you know that there aren’t even firm technical or legal standards to determine “non-compliance” to begin with? It is all very subjective and the system needs to be fixed. Sadly, the IAEA is haemorrhaging credibility – they really need to up their game and return to doing their real technical mission of nuclear materials accountancy.

 3.       What is wrong with the calculations in the AP diagram and what should the scientific results have been? Can you provide our readers with a rough estimation of the area such a bomb could wreak havoc on given the appropriate measurements?

There are two curves in the graph which show the evolution of power and energy as time progresses during a nuclear explosion – I’m assuming, of course, the diagram is related to nuclear physics for the sake of argument. Given either one of these curves, you can generate the other. Now if you actually do that with this diagram, you’ll find that you get a discrepancy of a factor of something like a hundred thousand: the two curves should correspond but they are off by a large factor.  Now some people have pointed out that you can apply a correction to the units shown on the graph which would fix the discrepancy. That is correct, but as distributed, the graph is wrong. It is a sloppy error that one would not expect from scientists working at, say, the national level. There is also another problem in that you would expect a sharp fall-off after the peak is reached in the power curve: a nuclear explosion does not have the nice almost-symmetric shape seen in the graph released by the AP. In fact, the power curve given in the figure is a little asymmetric but in the wrong way: the trailing part of the curve is longer than the leading edge.

Speaking roughly, a 50 kiloton weapon would wreak havoc on a good-sized portion of Manhattan with effects felt across both rivers in Hoboken in New Jersey and Queens on the other side. There would be secondary effects from radiation and fire also.

 4.       Do these measurements in any way correlate to the properties that would be seen if the Islamic Republic of Iran was to create a nuclear weapon, in regards to the full force of its explosive capacity?

It’s impossible to say, as the best US Intelligence indicates that there is no active nuclear weapons program in Iran right now. They do have the material, which if further purified, could be used as the fuel for making a bomb, but I am not aware of any specific design that Iran is developing. And the nuclear material that Iran does have is under the eagle-eyed surveillance of the IAEA.  In fact, following the release of the classified National Intelligence Estimate last year, Director of National Intelligence James Clapper confirmed in a Senate hearing that he has a “high level of confidence” that Iran has not thus far made any decision to weaponize. And the former head of the IAEA Mohammed El Baradei was quoted in a recent New Yorker article as saying he had not “seen a shred of evidence” that Iran was weaponizing during his 12 year tenure at the IAEA. So, we have no idea what kind of bomb Iran may develop should they ever choose to do so, because at the moment the best intelligence indicates that no such program even exists.

5.       Lastly, your article repeatedly refers back to the possibility that the diagram is a forgery and of an amateurish nature at best. Given the supposed lack of expertise and the fact that the diagram miscalculated the nuclear reaction, how probable do you think it is, from a scientific standpoint, that the diagram is a hoax?

It is impossible for me to say. It could be a hoax. Or it could be a genuine Iranian document. For example it could be that we’re seeing the results of some semester project that an Iranian physics student did. Similar unclassified models of nuclear explosions have been published in the West. It could even be that someone in Iran ran a computer simulation that was published in the West.  Of course, it could also be a graph that has nothing to do with nuclear physics, something that a professor did to illustrate some principles of calculus to his class. If we buy the Associated Press story, it could also be a rough drawing representing a nuclear explosion — in a vague and incorrect way — that some scientist threw together quickly to show some government officials, perhaps, in a plea to get additional funding. But even if we buy such a story, it would not mean that it represents Iranian government policy. Or, yes, it could be a hoax. The case for the Iraq war was also based on many fabricated documents and alarmist technical-sounding things – Yellowcake!  Aluminum tubes! — which the western media uncritically regurgitated. The point is such calculations or graphs have no place in an IAEA report – the IAEA is tasked with monitoring Iran’s declared nuclear material stockpile and making sure it is not diverted to any weapons uses, nothing else. The IAEA does not have a license to launch a wild goose chase into diagrams and calculations and cartoons that some scientists or students may have done.

The point, though is this, even if it is not a hoax, and even if the graph was technically perfect, it is still not a big deal. Nor do such theoretical computations contravene any legal agreements between Iran and the IAEA. Certainly, it doesn’t approach the seriousness of the computational work done in the Brazilian military institute on the American W-87 thermonuclear warhead.

  • Khalid butt

    A very detailed and interesting article.

  • [email protected]

    Iran’s nuclear program professedly computes the touchy drive of an atomic weapon, which the sources have named. It has been touted as confirmation of Iran’s atomic arms and purportedly an ability to build up a bomb with triple the hazardous drive of Little Boy, which the United States dropped on Hiroshima. The outline spilled to the Associated Press this week is just either trashy sources or terrible science.


Alexander Corbeil
Alexander Corbeil

Alexander Corbeil is a Substantive Analyst with The SecDev Group focusing on conflict and instability in the developing world. He has written on the topics of radicalization, sectarianism and terrorism in the Levant and Iraq for a number of publications and is also a contributor to Sada: Middle East Analysis. You can follow Alexander @alex_corbeil