Yesterday, I posted a story from the Associated Press on a document discovered by the IAEA inspectors that purported to show that Tehran was modelling the potential yields of a nuclear weapon.

Today, the Bulletin of Atomic Scientists has published a rebuttal:

This week the Associated Press reported that unnamed officials "from a country critical of Iran's nuclear program" leaked an illustration to demonstrate that "Iranian scientists have run computer simulations for a nuclear weapon that would produce more than triple the explosive force of the World War II bomb that destroyed Hiroshima." The article stated that these officials provided the undated diagram "to bolster their arguments that Iran's nuclear program must be halted."

The graphic has not yet been authenticated; however, even if authentic, it would not qualify as proof of a nuclear weapons program. Besides the issue of authenticity, the diagram features quite a massive error, which is unlikely to have been made by research scientists working at a national level.

The image released to the Associated Press shows two curves: one that plots the energy versus time, and another that plots the power output versus time, presumably from a fission device. But these two curves do not correspond: If the energy curve is correct, then the peak power should be much lower -- around 300 million ( 3x10⁸) kt per second, instead of the currently stated 17 trillion (1.7 x10¹³) kt per second. As is, the diagram features a nearly million-fold error.

This diagram does nothing more than indicate either slipshod analysis or an amateurish hoax.

In any case, the level of scientific sophistication needed to produce such a graph corresponds to that typically found in graduate- or advanced undergraduate-level nuclear physics courses.

While such a graphic, if authentic, may be a concern, it is not a cause for alarm. And it certainly is not something proscribed by the Comprehensive Safeguards Agreement between the International Atomic Energy Agency and Iran, nor any other international agreements to which Iran is a party. No secrets are needed to produce the plot of the explosive force of a nuclear weapon -- just straightforward nuclear physics.

Who might have the capability of producing such a graph?

Though the image does not imply that computer simulations were actually run, even if they were, this is the type of project a student could present in a nuclear-science course. The diagram simply shows that the bulk of the nuclear fission yield is produced in a short, 0.1 microsecond, pulse. Since the 1950s, it has been standard knowledge that, in a fission device, the last few generations of neutron multiplication yield the bulk of the energy output. It is neither a secret, nor indicative of a nuclear weapons program.

I have no reason to question this analysis - nor do I have the expertise. As far as the source, the BAS is a highly respected scientific organization not known for partisan or biased reporting, (although some have accused the group of politicizing their "doomsday clock" which some critics claim is more PR than science.).

I have found through the years that reporting on Iran's nuclear program can be sensationalized by the mainstream press which is why it's good to get other views of what is going on with the mullahs and their veiled program of nuclear research. (Another good source of opposing views on Iran can be found at Arms Control Wonks).

The Iranians are no doubt being secretive about certain aspects of the program; even the former head of the IAEA Mohammed ElBaradei scolded them for that. And the preponderance of evidence would indicate a military component to their research. They have been caught red handed doing research on warheads to fit their medium range missiles, and they failed to disclose a secret nuclear enrichment facility outside of Qom.

Prudent policy makers simply can't ignore this - especially when put together with the violent, eliminationist rhetoric of the regime toward Israel. This graph may or may not be a hoax, or a crude effort made by students to gauge the yield on a potential Iranian bomb. But those who see a catastrophe if Iran were to get the bomb can't dismiss it quite as easily as the BAS.