ISIS has published the IAEA Director-General’s reports on Iran and Syria.

Paragraph 35 of the Iran report reveals that Iran conducted “experiments involving the explosive compression of uranium deuteride to produce a short burst of neutrons” — research that has no known application other than for nuclear weapons.

Although this information was reported in December 2009, this is the most explicit IAEA confirmation of the allegation to date.

In December 2009, Catherine Philp revealed in the Times of London story the existence a 2007 “technical document” from from Iran that “describes the use of a neutron source, uranium deuteride, which independent experts confirm has no possible civilian or military use other than in a nuclear weapon.”

Subsequent DG reports on safeguards in Iran (such as GOV/2011/10) made mention of outstanding questions relating to “experiments concerning the generation and detection of neutrons” that “seem to have continued beyond 2004.”

One might have inferred that this was a reference to Philp’s documents, but this is the most explicit statement by the IAEA that Iran worked on uranium deuteride initiators.

That is an interesting fact because, as I pointed out in a post titled Uranium Deuteride Initiators, compressing uranium deuteride to generate neutrons is probably an unusual design feature of early-model Chinese and Pakistani nuclear designs.   This is such an unusual feature that when AQ Khan posed in front of a drawing of a nuclear weapon with  a “uran-deuteride initiator,” a lot of people scratched their heads until a couple of Chinese scientists from their nuclear weapons program published a paper titled “Fusion Produced by Implosion of Spherical Explosive,” in the proceedings of an American Physical Society meeting published as Shock Compression of Condensed Matter, (S. C. Schmidt, James N. Johnson, Lee W. Davison, editors, North-Holland, 1990.

This idea is so obscure that it didn’t even occur to nuclear weaponeers in the United States and Soviet Union — or if it did, it was forgotten. So, the practical implication is that this is a very specific trick related to nuclear weapons and implies AQ Khan provided nuclear weapons design information to Iran.

It is also worth noting that there is still some discussing in the open source literature about compressing uranium deuteride as a neutron initiators.  Geoff Forden wrote a nice primer on some of the more interesting questions.