I hate blogging the Iranian nuke kabuki because my grasp on the science is tenuous, which means any analysis is at risk of being totally wrong. When I read the Times story about Russia cutting off nuclear fuel to Bushehr, I wondered what the big deal was. Doesn’t Iran enrich its own uranium at Natanz? Why, yes — but it’s still a few years away from being able to enrich it highly enough to make a bomb, which means any bomb in the meantime would likely come from Bushehr. Can a bomb be made out of the nuclear fuel that Russia had planned to send to them for the Bushehr reactor? Why, yes, by extracting plutonium from the fuel after it’s spent — which is why Russia’s always insisted that Iran return all of the spent fuel to them. What if Iran ignores them and keeps the spent fuel for itself? That’s where we enter the danger zone:

Iran could try to pursue one of two reprocessing routes if it wanted to produce plutonium. Both pathways present unique challenges and limitations. First, as discussed above, within the next few years, Iran would likely have the large Bushehr nuclear power plant operating. This plant embodies the potential for dozens of nuclear weapons per year as long as Iran was willing to circumvent NPT restrictions, agreements with the IAEA, and the proposed agreement between Iran and Russia to ensure that all spent fuel from Busheher is returned to Russia. In order to handle the hundreds of tons of spent fuel, Iran would need a relatively large reprocessing facility.

Do they have a large reprocessing facility? Maybe. If they do, then according to a 2003 estimate, Bushehr could churn out enough plutonium for 30 bombs a year. Which makes Russia’s decision to turn off the tap, temporary though it may be, welcome news. Politically, too: they’ve been brainwashing the public for years about their sovereign right to nuclear energy, so if Russia pulls the plug now, Ahmadinejad’s got nothing to show for his presidency. Which is not a position he can afford to be in given his unpopularity.

Incidentally, per the blockquote, the second way Iran could get its hands on spent fuel would be by producing it through a heavy-water reactor of its own. They’re building one right now, at Arak, although it’ll be another few years yet before it’s ready. It’s also worth noting that highly enriched uranium has already been found in trace amounts at Natanz, which could mean that the enrichment facilities are much further along than thought or it could mean that the equipment still has HEU residue on it from when the Pakistanis (who sold it to the Iranians) were using it.

As for why Russia might suddenly have decided to put the screws to Iran, I honestly have no idea. It’s late in the game for them suddenly to be worrying about nuclear jihad. I can only assume we bought off Putin somehow; Captain Ed thinks so too. Whatever it is, it’s nice to know we won’t be the only target of his grandstanding tomorrow at the UN.

Exit question: Isn’t the logical thing for Iran to do here if they want a nuke to accept Russia’s ultimatum, suspend enrichment at Natanz, get some nuke fuel for Bushehr, and then restart enrichment at Natanz while refusing to send the spent fuel back to Russia? That’ll probably be the last nuclear fuel shipment they ever get from Putin, but so what? They’ll have bomb-making material on hand their own enrichment facility producing bombs within a few years.

Update: I don’t know what’s going on, but I likes it.

Update: Hmmm. Russia’s denying the Times report about its ultimatum.