Why eight days? Because that’s when Russia will start loading nuclear fuel into the reactor. Hit the site after that and you’ll create the equivalent of a giant dirty bomb, spreading fallout all over the surrounding area. Important question, though: Will having the reactor up and running actually bring Iran any closer to building a bomb? Why … no, not really. Michael Rubin:
While Ambassador Bolton, quoted in the piece, is certainly right that it would be extremely destructive to bomb a plant with loaded fuel (the Osirak strike in 1981 was timed to avoid that), the problem with the Bushehr reactor was never the Bushehr reactor itself, but rather suspicion (which, in retrospect, was justified) that the Iranian government would use Bushehr as a cover to important equipment to be used in a covert program. The problem is not Bushehr, but rather Natanz, Fordo, and the once-covert enrichment infrastructure.
That said, much of the discussion about an Islamic Republic of Iran with nuclear weapons revolves necessarily about how that will change the regional balance and complicate U.S. security concerns.
Our own J.E. Dyer made the same point in an excellent post 10 days ago. Take five minutes to read it, because Bushehr going online next week will be a big deal notwithstanding its small role in Iran’s weapons infrastructure:
First, the technical reality. Bushehr is not an efficient source of weapons-grade fissile material. Lighting off the LWR would advance Iran’s program to develop nuclear weapons hardly at all, in the context of any operationally significant timeline. It matters, yes; but not soon. One LWR would take years to produce a meaningful amount of weaponizable material. (The heavy-water reactor being built in the north at Arak, on the other hand, can produce plutonium – like North Korea’s plutonium reactor – somewhat more efficiently. Weaponization is a different design problem in that case, but the foreign associations of Iran’s nuclear program suggest both avenues have been pursued.)
Therefore – and this is important to understand – the change of conditions represented by Bushehr going critical is not centered on what this event means to the timeline for a nuclear weapon. Israel may well not regard it as essential to strike the reactor and prevent it from being brought online. The US certainly may not (and in my estimation, probably doesn’t). Iran’s ability to produce a weapon is based on centrifuge enrichment of the current uranium stock, combined with laboratory testing of detonators and the design and testing of warheads. Striking the LWR at Bushehr affects none of these elements of the program.
I’ve written about this subject before too, but nuclear tech is way above my pay grade. The basics are this: In theory, because Bushehr will produce spent nuclear fuel in the form of plutonium, given a long enough time frame the Iranians can harvest that fuel and build a Nagasaki-type bomb from it. I emphasize that that’s only in theory, though: Experts note that Bushehr will produce the wrong type of plutonium needed for a bomb — mostly Pu240, Pu241, and Pu242 instead of Pu239 — and if they did try to make the right kind, they’d inevitably have to tip their hand by sealing the reactor to outsiders, kicking out inspectors, moving the spent fuel, etc, in order to do what needs to be done. (An ominous caveat: According to the last section of this Global Security analysis, other experts insist that making a plutonium bomb without Pu239 isn’t as difficult as thought.)
So what’s the big deal about Bushehr then? Well, like J.E. says, if Russia presses ahead and agrees to start loading the fuel next week, it’ll be a middle finger to The One and his “reset button” efforts. It’ll also likely spook a bunch of Sunni countries — as Bolton notes, this is the first time an Islamic regime in the region will have succeeded in bringing a reactor online — which means god knows what for Middle Eastern politics for the rest of the year and beyond. As a not-so-wise man once said: Gird your loins.