James ActonGeneva: The TRR and Enrichment Abroad

Long time, no speak. Time for a spot of guest blogging at this busy time.

Interesting news from the meetings in Geneva today. Iran has agreed, “in principle”, to have some LEU from Natanz further enriched abroad and fabricated into fuel for the Tehran Research Reactor. (You might remember President Ahmedinijad recently floated the idea of the US supplying fuel for this reactor which is apparently close to running on empty).

Apart from being an interesting confidence-building measure, it’s obvious why Iran might go for this—it needs the fuel. It’s also obvious why the E3+3 like the idea. Julian Borger reports that:

Western officials here say that to restock the TRR, Iran would have to send out up to 1200 kg of LEU. That’s about three-quarters of what they’ve got, and it would be out of the country for a year. When it came back it would be in the form of fuel rods, so it could not be turned into weapons grade material in a quick breakout scenario.

Let’s look at the practicalities of this, because it turns out there might be one potential sting in the tail.

According to NTI, the Tehran Research Reactor (TRR) requires 115.8 kg of 20% enriched fuel. We don’t know the average enrichment of the LEU at Natanz (the maximum is known to be 4.4%), so let’s assume it’s 4% (nice round number and all that). Let’s also assume that the ratio between the product and tails assays is 10, roughly the same as for enrichment from natural uranium to LEU for power reactors. I don’t know for sure this assumption is valid but I believe it is.

If you crunch the numbers (very straightforwardly) then you find that 1040 kg of uranium from Natanz is needed to produce one load of fuel for the TRR. If you assume the average enrichment of the LEU at Natanz is 3.5% then 1390 kg is required. Very much in the right ball park.

My guess (and it is only a guess) is that the enrichment will take place in Russia—at Novouralsk (see page 85 of the 2007 GFMR). Based on what I know about how other states have enriched to 20% or more, Russia probably does not go directly from natural uranium to 20%. I would expect it to enrich first to 3—5% and then to go to 20% in a second stage. If so, using Iranian LEU as feedstock for this second stage should pose few problems beyond, perhaps, a bit of blending to fine tune the enrichment to whatever the Russians normally use, providing that the Iranian material is sufficiently pure.

And here’s the crunch.

Remember the whole molybdenum thing?

The problem gets worse at higher enrichment levels and can cause centrifuges to crash. Although many have assumed than Iran has solved the problem and can produce uncontaminated UF6, we don’t know for sure. But, you can bet that the Russians are going to check this before sticking Iranian LEU into their cascades.

Technical problems could yet derail this interesting initiative…


  1. R. Scott Kemp (History)

    In the world of commercial enrichment, you never get back the same uranium you submitted for enrichment. It’s like currency: Some cash is deposited into the vault, and what comes out is a fungible equivalent. The molybdenum concern is not a showstopper—if that problem even exists.

    It is almost certain that this enrichment would be done in Russia. European plants are not licensed to go above 5%.

  2. James Acton


    That was my initially my thought, but this isn’t normal commercial enrichment. I could see Iran insisting that its uranium be re-enriched and re-imported. This seemed to me to be what the statements from Geneva were hinting.

    But, if Iran doesn’t insist on this then, yes, flag swapping would surely occur.


  3. Tom F (History)

    Given the size of Iran’s indigenous uranium deposits if they insist on it being “their” uranium it’s more likely to be Venezuela’s the way it’s going.

  4. Corentin B (History)

    There are French reports stating that France may have accepted a US offer to make the fuel rods from the 20%-enriched Iranian uranium. An internal note from French MoFA confirming this information was very recently leaked in the press. For those of you who can speak French : http://www.bakchich.info/Le-cadeau-atomique-de-la-France-a,08836.html

  5. Rwendland (History)

    Does anyone know where Argentina’s INWAP enriched the current fuel load to near 20%? This paper says the Pilcaniyeu Gaseous Diffusion Plant is only designed for 5% enrichment, so probably not there.

    It would seem to make a lot of sense for INWAP, who converted TRR from the U.S. 93% HEU to near 20% LEU, to fabricate the replacement fuel, if not do the enrichment. And I’d guess Iran would quite like a non-aligned country to be involved. The delays on Bushehr probably haven’t helped reliabliity perceptions of Russia in nuclear matters.

  6. lizz (History)

    Interesting to see if the Iranian uranium ever makes it back, or if it becomes held up by sanctions and politics. Iran is testing the West to see if they can be trusted.

    Meanwhile on the question of when Iran should have declared the QOm enrichment facility

    If the decision to construct the facility was made before Feb. 26, 2003, and the preliminary work also began before that date, then Iran has not violated any of its obligations under the Safeguards Agreement. In fact, there is nothing in the Safeguards Agreement that says that the modified Code 3.1 should be applied retroactively. If that were the case, even the Natanz facility would have been illegal, which it is not.

  7. Andy (History)

    Interesting development which brings up a couple of questions.

    1. Why isn’t Argentina supplying the fuel (I had thought they had an agreement with Iran) and will the spent fuel be returned to Argentina?

    2. My understanding is that the original US-supplied 93% enriched spent fuel load remains in Iran. Is there any mention of sending this spent fuel back to the US?

  8. nick (History)

    I think this is much ado about nothing. Wouldn’t you think that an experienced operator, such as Russia, will check for all impurities, including molybdenum?

  9. Ben D (History)

    James said, “My guess (and it is only a guess) is that the enrichment will take place in Russia—at Novouralsk (see page 85 of the 2007 GFMR).”

    Why not France since Eurodif is 10% owned by Iran?
    PARIS, Sept 29 (Reuters) – A French plant that produces a quarter of the world’s enriched uranium is 10 percent owned by Iran, which has had the stake for more than 30 years, nuclear reactor maker Areva said on Tuesday. / quote.

  10. Azr@el (History)

    And the Iranians outmaneuver us again; big surprise. They’ve put forth a prize too sweet for us to pass on, half to three quarters of their current stock of LEU, and now talks are ensured to last ‘til the second coming. In the meantime, no suspension and no second TRR to warrant further sponging up of Iran’s new stocks of LEU via fueling swap.

  11. Benham (History)

    ** QUESTION: **

    Would the West have agreed to provide fuel for Iran’s medical reactor if it had not been for the fact that Iran has a civilian enrichment program which gives it leverage?

    I think the answer is no.

    Iran’s refusal to suspend enrichment has now born its first fruit.

    Remember: just a few years ago the Americans were opposed even to the Bushehr nuclear reactor! They have now dropped that objection.

    The West would deprive Iran even of hydroelectric power if it had the means to do so, let alone of peaceful nuclear energy. The Iranians have learned the hard way not to assume good faith on part of their negotiating partners. The unceasing chant, “all options are on the table,” has driven that point home in the starkest manner possible.

  12. R. Scott Kemp

    State Department Notes on the History of this Proposal

    Iran came to the IAEA a few months ago with the request to replace this supply. The IAEA consulted us and some others, some other members, and to make a long story short the United States and Russia joined together in a proposal to the IAEA which the IAEA subsequently conveyed as a response to the Iranians, to use Iran’s own LEU stockpile as the basis, as the feedstock for the reactor fuel that’s required.
    This would then entail taking its LEU, which is enriched to about 3.5 percent, enriching it up to 19.75 percent in Russia, which the Russians have now publicly confirmed that they’re prepared to do, and then fabricating that into fuel assemblies which can be used at this safeguarded reactor, and the French have now confirmed their willingness to play that last role.

  13. Miles Pomper (History)

    Good discussion
    First of all, a point of authorship. The information on the NTI site about the TRR is actually from CNS, so it should really be “according to CNS”.
    Also it should be noted that Iran was involved with efforts with IAEA to convert facility to LEU. See chart in Bill Potter’s article in July 2008 Nonproliferation Review.
    Finally a question. I agree with Scott’s supposition—Russians will simply use their own fuel. Is there really a way Iranians could tell otherwise? I suppose that there would be a particular signature…

  14. Sharon Squassoni (History)

    It seems obvious that the West would want Russia, rather than Argentina, to supply the 19.75% LEU; it’s not clear where INVAP ever got the enriched fuel to send to the Iranians since PIlcaniyeu never really worked (and I don’t think it does to this day). Moreover, this gives Russia the opportunity to take a closer look at the Iranian LEU. The French entity CERCA manufactures TRIGA fuel, so the French are an obvious choice for fuel fab.

  15. Pavel (History)

    Even if Iran insists for some reason that it is its material that should be used, Russia would not have to put it through centrifuges – it could use its HEU stock. Shouldn’t take much of the stuff.

  16. mark hibbs

    It won’t make any difference to Iran whether the uranium enriched and fabricated in Russia into fuel for TRR or any other reactors in Iran, including Bushehr, is Iranian origin or not (note that the first cores for Bushehr-1 are made with Russian-origin EUP)—unless after discussion with other P-5+1 Moscow were to attach nonproliferation or commercial restrictions to the Russian material when they flag-swap it. Stay tuned.

  17. Alex (History)

    @Pavel and others: You are correct. To my knowledge, no one ever produced 19.75% enriched material directly; LEU at that enrichment level is always downblended material.

  18. Brian (History)

    I can’t recall if the Russian plan from 2006 to enrich Iranian uranium for Bushehr also entailed the manufacture of fuel assemblies. If the current plan is just a resurrection of the 2006/7 proposal, that’s one thing. On the other hand, the Iranians have claimed that FMP is capable of producing fuel assemblies for both HWR and LWR. (Unlikely.) Maybe they’ve realized their facilities aren’t as capable as their bombast suggests. Wouldn’t that be a surprise?

  19. Mark (History)

    This should be a good opportunity (beyond the stated benefit of having this LEU tied up in research reactor fuel). I’m sure there’s quite a bit you could learn about the efficiency of their enrichment and conversion processes by studying it closely, especially such a large sample of LEU.

    I think we should work with the Russians to take possession of the LEU from Iran and switch it for some other 20% fuel, and spike the fuel we send back with some isotope tracer so that in the unlikely event that Iran does divert it for some nefarious purpose, the attribution/identification will be a cinch.

  20. Scott Monje (History)

    A naive question regarding molybdenum: If contaminated uranium causes your centrifuges to crash, why would anyone swap for it?

  21. Rwendland (History)

    Re Pilcaniyeu: contrary to the DOE-ARN report I cited above, Albright in BAS May 1989 more plausibly states the Argentinian Pilcaniyeu Gaseous Diffusion Plant was intended to produce 20% LEU for research reactors, and possibly submarine reactor fuel. As the plant worked poorly Argentina bought 150 kg of 20% LEU from the Soviet Union to support INVAP’s research reactor export business (see INFCIRC/297). Another less reliable source states they also imported more 20% LEU from China later (no obvious INFCIRC covers this though).

    So the current TRR fuel LEU probably originated from the Soviet Union, or possibly China.

    Albright also comments that it was the U.S. under Carter cutting off supplies of research reactor fuel that prompted Argentina to build the Gaseous Diffusion Plant.