On the last exciting episode of “Iranian Nuke Kabuki,” western diplomats revealed that Iran had designed a new type of centrifuge capable of enriching uranium more efficiently than their current antiquated models. Instead of needing 3,000 of the old units to produce material for one bomb, they need 1,200 to 1,500 of the new ones. The good news today? Allegations from Ahmadinejad that, yes indeed, they do have some new and improved technology in this vein and that they’re planning to install 6,000 new centrifuges at their facility in Natanz. Are those 6,000 old models or new models? Only the Mahdi knows:

President Mahmoud Ahmadinejad says Iran has tested new advanced centrifuges to enrich uranium, a breakthrough in a program that the U.N. has demanded the country halt.

The hardline president says a “new machine was put to test” that is smaller but five times more efficient than the already used P-1 centrifuges…

Iranian state television didn’t say if the installation of the 6,000 new centrifuges included the older P-1 or the advanced IR-2 centrifuges.

It’s not a simple matter of installing the centrifuges; they have to be able to run them nonstop, and in linked cascades. That’s a major technical hurdle, as I understand it (as is procuring or manufacturing the parts), but once that’s cleared it’s a question of processing the uranium and waiting until you have the mass needed for a weapon. There are already 3,000 centrifuges installed at Natanz, so even if the new batch are old models, in theory they’ll have the capacity to produce enough highly enriched uranium for a single device in four months.

Any reason to doubt this? Yeah — for one thing, it’s national nuclear day in Iran (the second anniversary of enrichment activities), so Ahmadinejad’s probably inflating what he’s got, either in terms of the number of centrifuges or their technological progress or both. Arms Control Wonk predicted a “grandiose” claim in this vein several days ago, and here we are. But follow the link for the bad news: According to some diplomats, they’ve already got hundreds of the advanced models linked up in cascades. From the AP:

One diplomat said more than 300 of the centrifuges have been linked up in two separate units in Iran’s underground enrichment plant and a third was being assembled. He said the machines apparently are more advanced than the thousands already running underground.

But a senior diplomat said that while the new work appeared to include advanced centrifuges, they were not IR-2s.

Not IR-2s? What are they, then? Next time, on “Iranian Nuke Kabuki”!

Update: That saber’s rattling awfully loudly:

Israeli Minister of National Infrastructure Benjamin Ben-Eliezer warned on Monday that if Iran attacks the Jewish state, it will suffer widespread destruction as a result.

Speaking at the headquarters for Israel’s largest ever national emergency and defense drill, Ben-Eliezer said that “an Iranian attack will prompt a severe reaction from Israel, which will destroy the Iranian nation.”