(the last of this monster) With this more enriched uranium feed, the level of effort or time Iran would need to make weapons grade uranium would drop very significantly (i.e., it would take less than one quarter the time to produce weapons grade uranium starting with 19.75 percent enriched feed than it would if Iran started with 3.5 percent, for more details see Greg Jones, "Iran's Centrifuge Enrichment Program as a source of Fissile Material for Nuclear Weapons: An Update," August 17, 2009 available at http://www.bipartisanpolicy.org/sites/default/fil... also posted on www.npec-web.org). In Iran’s case, assuming one was using 5,000 of the machines at Natanz that were only 20 percent efficient, you would be talking about a reduction from roughly 5 months of effort to get weapons grade uranium, to something slightly less than four weeks.
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(this post continues the posts above) In any case, the report explains why it would be worth getting at enriched fuel even if it is in fuel rods. As is explained in the report, only modest effort would be required to open reactor fuel cladding and then to prepare the fuel so it can heated and fluorinated. The result for Iran would be having access to roughly a bomb’s worth of UH6 enriched feed that was enriched not to 3.5 percent, but to 19.75 percent. (for the last of this post, see below)

(this post continues the post above) Abrupt diversion must be a concern especially in cases where the diversion could lead to nuclear weapons materials being produced in a relatively short time (i.e., days or weeks). Also, because Iran refuses to allow near-real time surveillance, gradual undetected diversion is still possible). This later point was highlighted by Dr. Marvin Miller's safeguards analysis as well as diversion scenarios developed by the IAEA’s safeguard advisory group. (this post continues below)

(this post continues from the post above) As for the chance that Iran might seize the enriched fuel they might get from France or Russia, I agree with Mr. Lobe's assessment that this hardly the most likely scenario for Iran making its first bomb. That said, it ought not to be dismissed as a weapons material source per se. A good place to start for the analysis on this point is Victor Gilinsky, Harmon Hubbard, and Marvin Miller, "A Fresh Examination of the Proliferation Dangers of Light Water Reactors," http://www.npec-web.org/Frameset.asp?PageType=Sin... at pp. 14 and 41. This report, which Amory Lovins, Los Alamos National Laboratory, the IAEA's safeguards advisory group, the U.S. State Department, and the Natural Resources Defense Council’s own analyses have corroborated, describes the relative ease of diverting LEU fuel either abruptly or gradually. (see below for the rest of this post)

(this post continues from the post above) If this is how Iran proceeds, Iran would be able to keep roughly 500 kgs of the LEU it has already produced (i.e, enough to make 15 kgs. of weapons grade uranium, which is nearly the full 20 kgs. conservatively estimted to be needed for a bomb's worth). It is worth noting that it would take Iran no more than five to 10 more months for to produce yet another 500 kgs of LEU. Long story, short, as long as Natanz continues to enrich uranium, we are, at most, only a few months away from it acquiring all it needs to fuel its first bomb. This is the case, even if Iran decides to send all of its LEU out of country today. (this post continues below)

I think this piece is spot on correct about the need to follow up whatever was agreed to in Geneva with much stricter restrictions on Iran's nuclear fuel making activities. Unfortuantely, it is still not clear when Iran will send out its lightly enriched uranium or how much it will send out. Clarification of these points must await upon further negotiations later this month. In any case, I undersand that Iran only needs roughly 70-80 kilograms of fresh 19.75 enriched fuel to keep its research reactor running for another five years and that it can run the reactor with what it has on hand for another 12 to 18 months. This gives Iran some time before it has to send any of its low enriched uranium to Russia. In any case, to produce the 70-80 kilograms of fresh fuel, Iran would only need to send Russia roughly half (i.e., 500 kgs.) of the low enriched uranium (LEU) Iran already has produced. (this post continues below)

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