Jeffrey LewisUranium Deuteride Initiatiors Redux

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.


  1. FSB (History)

    Yes, that Iran had a nuclear weapons program in 2003 (maybe going even into 2004 a bit) is well known, and it is great to have this bit of historical trivia about the triggers.

    That said, and as you reported Clapper as saying, Iran has not re-started that program “with high confidence”, according to the one person in the US who ought to know:

    Old hat.

    • sanman (History)

      But you and your supporter Anon are claiming that it’s “impossible to prove a negative” – in which case how can you credibly negate the existence of Iran’s nuclear program following 2003, since it’s “impossible to prove a negative”??

      North Korea has on multiple occasions pretended to have mothballed its nuclear program in order to get concessions, only to show later on that it was still active, in order to repetitively seek more and more concessions and carrots.

      And what collateral or bond will you put up, if your buddy Iran flies the coop? What happens if it breaches its signed obligations, which it has repeatedly upheld in statements made to the international public?

    • FSB (History)

      Iran is not my buddy.

      The CSA is my buddy.

      Go read it.

      Also google “Proving a negative”

      Then read what the DNI said.

  2. Arnold Evans (History)

    I’ve meant to ask, but what did Iran sign or ratify that forbids “experiments involving the explosive compression of uranium deuteride to produce a short burst of neutrons”?

    I assume Japan has done research into these things if only to inform its assessments of the programs of North Korea, South Korea, Taiwan and China. I also assume that because these steps are far short of assembling nuclear weapons, they are not forbidden by the documents Japan has ratified. Of course, the same holds for Iran.

    Assuming these experiments, if they happened, were done with small enough quantities of fissile material, wouldn’t these experiments be perfectly legal?

    • sanman (History)

      If FSB had any basic technical or scientific literacy, he’d recognize that neutron scanning can be done far more efficiently and effectively than having to explosively compress fissile material. If you’re trying to achieve explosive compression of fissile material, it’s pretty much a dead giveaway what you’re trying to do.

      FSB says: “You heard screaming at my house, followed by gunshots? Nooo, noo, you must be mistaken, that was just ordinary merriment, and celebratory gunfire! Bloody handprints on my walls? Nooo, nooo, that’s wall-paper patterning custom-designed by yours truly!”

      While FSB cites the Onion, he seems to model his own style of argument after Monty Python’s Black Knight:

    • FSB (History)

      Read the CSA.

      Also google “Proving a negative”

      Then read what the DNI said.

  3. Mark Lincoln (History)

    All very interesting but why would someone with easy access to a common oil field device like Compact Neutron Generators waste time pursuing antiquated means of initiating an explosion which are dependent upon compression for their timing?

    • FSB (History)

      hmmm, maybe they were looking for replacing the oil field device — maybe the oil field device was restricted under the sanctions(?)

      Perhaps it was not for weapons(?) — could it be this?:

    • Jeffrey (History)

      Not the same sort of neutron generator. The only known use for generating neutrons by imploding uranium deuteride is generating neutrons for early generation Chinese and Pakistani nuclear designs.

    • Allen Thomson (History)

      Well, if this U-D device works as described, it would have the advantage (like the Urchin Po-Be initiator), of not requiring any precision timing electronics like an external neutron tube would. It just does its thing when the density gets high enough.

      Which leads to a question: again assuming it works as advertised, what advantage would U-D have over Po-Be? Maybe producing neutrons when the overall assembly had reached a higher density?

    • Jeffrey (History)

      Dear Mark:

      I think I initially read your comment the wrong way. Sorry. You are correct. There is no reason to pursue antiquated means of initiating an explosion which are dependent upon compression for their timing.

      I think I need to take a tougher hand moderating comments.

  4. Andy (History)

    FSB / Anon,

    There are obviously legitimate uses for neutron generators, but not all neutron generators are the same. We are talking here about a specific technique – generating neutrons through explosive compression. That is not a technique that would be used to test the integrity of oil tanker walls or in medical imaging or any other commercial application that I’m aware of. These links to papers describing neutron generators for commercial purposes are therefore irrelevant.

    • Andy (History)


      To quote Jeffrey above, “The only known use for generating neutrons by imploding uranium deuteride is generating neutrons for early generation Chinese and Pakistani nuclear designs.” In other words this research won’t produce a substitute device for those Iran is unable to import.

      Secondly, if Iran had a weapons program in 2003-2004 but abandoned it, as you seem to suggest, then they have an obligation to disclose that to the IAEA and allow the Agency to definitively verify that the program is, in fact, abandoned.

    • Anon (History)

      No because the IAEA is politically motivated and that, in any case, would be trying to prove a negative.

      People have tried to explain this to you before on this blog.

    • Andy (History)


      That you perceive political motivation (a perception not everyone shares) does not change a nation’s treaty obligations, nor does it change the IAEA’s obligations with respect to Iran or any other country. The DNI’s opinion is irrelevant to those obligations.

    • sanman (History)


      What are you babbling about? Impossible to prove a negative? Then why have the NPT at all, when it requires non-P5 states to be nuke-free – a negative condition which you claim is impossible to ascertain, establish or prove?

      Or are you just going to claim that it’s impossible to prove negative only in the case of Iran? If it’s impossible and thus useless to determine whether NPT signatories are nuke-free, then what is the use of the NPT?

      Indeed, what then is the use of arms control as a field of endeavor to begin with?

    • Anon (History)

      Kindly read the CSA.

  5. Ben (History)

    “After the US invasion of Iraq, if Iran isn’t developing a nuclear deterrent, they’re crazy”

    – Martin van Creveld, One of Israel’s leading historians.

    I don’t intend to be a serial controversialist, but, after some thought, I’ve come to the unradical conclusion
    that Iran already has nuclear weapons.

    And what’s more, it’s likely the US and Israel know about it.

    Either acquired illicitly or manufactured covertly,
    it is, in the end, the only way I can account for the real lack of urgency in this now 24 year long program (surely a world record marathon R&D effort for any state wishing to acquire a nuclear deterrent).

    Lets be clear, there is NO urgency in the Iranian weapons program – no urgency and no clear resolve, this, despite the massive increases in the scale of threats Iran now faces.

    There isn’t the frantic determination of Israel in the 1960’s (which audaciously resorted to theft at NUMEC), there isn’t the entitled determination of India or the commensurate riposte of Pakistan, there’s isn’t the delusional dedication of South Africa or the ambitious,
    secretive obstinacy of North Korea.

    Are we really to believe the Iranian program is MORE shambolic and unfocused then that of Iraq? It isn’t, but it lacks a similar drive.

    Where did Iran get it’s weapons from? Where do we start?There were reports in the early 90’s Iran acquired 4 warheads from Kazakhstan, wikileaks repeats the rumour, only this time Iran acquires an unspecified number of warheads from the Ukraine. Maybe the fissile material was bought from Russia. China is an outlier – but I wouldn’t put it past them. North Korea is the obvious, most probable source – it’s enrichment program probably reached fruition earlier then most analysts estimate. It’s highly likely.

    That Iran tried to buy weapons from Pakistan is almost certainly true.

    Pakistan says it didn’t sell them and the Iranaians went away empty handed. Is this neat and convenient ending to this story wholly believable? -no, not completely.

    Of course there’s always that pesky possibility of a covert facility. But Iran’s program is suprisingly open.
    A driven state would have withdrawn from the NPT long ago.

    There will not be an attack on Iran, by the US,
    Israel or anyone else. Do I think they’re trying to limit the number of extra weapons Iran might try to produce domestically? Of course. But the US would never have
    let Bushehr go critical if they hadn’t been totally sure
    Iran hadn’t already crossed the nuclear threshold.

    In short, I think the game’s over, and the writing is on the wall.

    • Mark Lincoln (History)

      The sudden end of threats to attack North Korea following it’s first ‘test’ certainly had to be noticed by Iran.

      If iran had any bombs a single test would end the endless threats to attack it.

      While several nations possessing nuclear weapons did not test them within their borders until necessary for political/diplomatic reasons, it seems unlikely that Iran would have not tested if it had any bombs.

  6. Barmak (History)

    That document about neutron source was a cheap forgery:

    The author’s Farsi is very poor. That’s odd if he is an Iranian nuclear physicist.

    Also the document is written in Arabic font instead of Farsi font (there are small differences between Arabic and Farsi alphabet, kind of like English versus German). Arabic font is more accessible on English language computers, which is handy for making Farsi forgery if you are not in Iran.

    I can’t be sure about the physics part because I know very little “Farsi physics” and I don’t know nuclear physics. Maybe some Iranian physicist reads this and you can help me out. The document talks about “neutron cheshm-eh”, I think cheshm-eh refers to neutron beam and things like that (radiation out of a single exist). The word for neutron source should be “neutron manba’a”, which is not mentioned in the document. I don’t know what would be the word for “neutron initiator”, whatever it is, it is not mentioned either.

    I bet this was originally a paper about neutron detectors, neutron activation or something, then somebody took it and modified it for neutron initiator, not knowing the correct replacement words. That would also explain the inconsistencies in the document. Note, in some parts the author gives proper information about experiments and proposals. In other parts, he gets all secretive and his Farsi gets very bad at the same time. For example he writes “this work shall be done by the folks who work at the institute … nobody must find out about it …”

    • George Maschke (History)

      Barmak, I also noted that an Arabic font was used in this document (see:, and in response, Oliver Kamm of the Times of London acknowledged that the document it published was not original but had been “retyped.”

      With regard to the use of the word “cheshmeh” (source) I see nothing unusual. A Google search for “cheshmeh-ye nutroni” (چشمه نوترونی “neutron source”) yields 776 results, whereas a Google search on “manba’-e nutroni” (منبع نوترونی also meaning “neutron source”) yields only 281 results.

      I see nothing in the document that would lead me to believe that the author is not a native speaker of Persian.

    • Barmak (History)

      Hi George,
      Thanks for explaining the Arabic Font. But that’s what The Times said, only after you caught them with this obvious forgery. Initially this was supposed to be the original Farsi document.

      Neutron source is “manba’a-eh notron”, not cheshm-eh. Try these google searches:
      UD3 چشمه نوترون
      UD3 منبع نوترون

      Also I didn’t say the author is not a native Farsi speaker, I said his Farsi stinks and he is a moron. He could be the Iranian equivalent of Iraq’s Ahmad Chalabi, Curve Ball, etc.

      Even the English version doesn’t make any sense. It proposes “secret mobile labs”, it mentions UD3 etc. which suggests they are up to something. But the rest of it is about neutron sources(!) and neutron detectors, which have many civilian applications. It’s not clear why they need to get in to a moving van to pursue this project, or what it is they intend to do.

  7. JK (History)

    ‘This initiator uses fusion materials and does not require polonium-210. This isotope, with a relatively short radioactive half-life, must be produced typically in reactors and can severely complicate the construction and deployment of a nuclear arsenal. The provision of this type of long-lasting initiator would have been a tremendous gain for Pakistan’s fledgling nuclear weapon program.’

    p. 50, Peddling Peril (David Albright 2010)

  8. Jeffrey (History)


    There are neutron generators and there are neutron generators.

    This method is incredibly unique. Not only are there no civilian uses for imploding uranium deuteride to generate a burst of neutrons, NOT EVEN THE OTHER NUCLEAR WEAPONS PROGRAMS CONSIDERED THIS APPROACH. (Or, if they did, the design approach was forgotten.)

    Let me say that again. This is such an unusual thing to do, it it is not merely indicative of nuclear weapons work. It is indicative of Chinese nuclear weapons work.

    That picture of AQ Khan standing in front a diagram with “uran-deuteride initiator” is the most damning piece of evidence that China provided Pakistan with nuclear weapons design information. If these documents are authentic, this would indicate that this information as further passed to Iran.

    • Hairs (History)

      I don’t normally get all philosophical about nuclear issues, but I think we need to reach for Marcus Aurelius’ Meditations and then ask of a uranium deuteride neutron source, “What is this thing in itself […]? What is its function in the world?”

      If China developed a functioning uranium deuteride source, and then passed it on to Pakistan, who seem to have passed it on to Iran, then there must be a utility to this solution that we’re missing. Maybe alternative neutron generators are too difficult to produce because sanctions block the import of some critical component; maybe Iran can’t be bothered with the logistical problems associated with tritium in DT tube initiators; maybe it’s just an off-the-shelf solution that means they could create a functional (if inefficient) weapon as soon as the fissile material is ready rather than facing delays while a more elegant initiator is developed; maybe etc…

      I don’t pretend to know the answer, but referring back to Geoff Forden’s primer I think some commentators are looking down the wrong end of the telescope: countries staff a nuclear weapons programme with the best scientists and engineers they can get – guys who are far from stupid, so if Iran has a weapons programme, and if they are using explosively-compressed uranium deuteride as an initiator, then they have a damn good reason for choosing to do so. If we can second-guess that reason then there’s a good chance we’ll learn something about the progress of, or constraints on, any weaponisation programme.

      For what little it’s worth, I believe compressed uranium deuteride would be chosen because (I assume) it is a proven design i.e. surely either China or Pakistan has actually tested such a design. If so it’s the nearest Iran would get to an off-the-shelf weapon with no worries about maintaining tritium or polonium components. If so then the use of uranium deuteride represents a desperation to get *a* nuclear weapon as soon as possible, as well as a need to avoid a test programme.

    • Jeffrey (History)

      I believe the appeal of an off-the-shelf design is a deliverable missile warhead that Iran (or another state) would not have to test.

      The South Africans discovered early on that a test (or, really, a demonstration) was an important threshold that could be crossed overtly to signal resolve. The North Koreans and Pakistanis both treated the act of “testing” as a demonstration, as I suspect will our Farsi-speaking friends in Iran.

  9. nukeman (History)

    You can find an actual description of some of Iran’s experiments done by Abbasi on neutron generators at:

    International Workshop on Real Time Measurement, Instrumentation and Control, Toronto, Ontario, Canada, June 25-26, 2010, P. Tayyebi and F. Abbasi Davani
    Design and Construction of Deuterium Target for Fast Neutron Production

  10. FSB (History)

    Thanks for deleting my posts and letting that flame thrower idiot Sanman’s posts intact. Quite fair.

    • Jeffrey (History)

      I am moderately irritated that you seem to be posting under three names.

    • FSB (History)

      My zenmaster, parole officer and 3 other colleagues and I share the WLAN. If one of our comments is censored we talk among ourselves and see if a very similar comment by another is let through. It’s rather amusing actually.

    • Jeffrey (History)

      It must very crowded inside your van.

    • FSB (History)

      Back on topic: more hot air from Broad at the NYTimes — reporting “News” from 2003…Sanger is taking a breather — good for him.

      Yes, Iran had maybe some nuclear weapons research in 2003 but no longer does it have a weapon programme according to our DNI. I tend to believe the DNI more than the NYTimes.

      Where does Broad mention in his piece that everything that the IAEA talks about and that he reports on is outdated?

  11. blowback (History)

    The language used in section 35 seems a bit stilted.
    “Since the last report of the Director General on 25 February 2011, the Agency has received further information related to such possible
    undisclosed nuclear related activities, which is currently being assessed by the Agency. As previously
    reported by the Director General, there are indications that certain of these activities may have continued
    beyond 2004. The following points refer to examples of activities for which clarifications remain necessary
    in seven particular areas of concern:”
    “ Neutron generator and associated diagnostics: experiments involving the explosive compression of
    uranium deuteride to produce a short burst of neutrons.”

    From this, it would appear that Agency has received further reports, but we are not told what they cover.

    The Agency then lists examples of issues that require clarification.

    As far as I can see, there is nothing in this report to tie the compresssion of uranium deuteride experiments to the further reports just received other than the fact that they appear in the same section of the IAEA report. Now this could be an act of omission by whoever wrote this report but that is unlikely because of the review process that such reports go through. So that means that whoever wrote and reviewed this report within the IAEA wished to tar Iran with “evidence” that does not exist. Such careful use of words does not happen by accident.