I finally got more on yesterday’s AP story about Iran’s barring inspectors from its enrichment facilities. The upshot is that Iran has not blocked IAEA access to any of the facilities where it is currently conducting uranium enrichment (as the wire story seems to suggest). That would indeed have caused an immediate international crisis. What happened, according to a diplomat close to the IAEA, is that Iran blocked access to a certain part of the deeply buried commercial-scale Natantz enrichment facility that is still under construction. Planned nuclear facilities under construction are subject to occasional preparatory inspections, and here one team of inspectors was recently refused access. But they haven’t tried to go back, and they don’t expect to be denied access again when they do go back. Ergo, the AP story is accurate but critically imprecise.

The pilot facilities where Iran continues to enrich Uranium are too small to produce a weapons-usable quantity of weapons-grade uranium within many years. On the other hand, once the commercial-scale enrichment cascade now under construction at the Natantz complex is completed, Iran might be able to start enriching enough uranium for several weapons a year in a matter of months. In sum, Iran has now committed another serious breach of the nonproliferation treaty, but we have not yet gotten to the point of no return….