While Iran has produced about 43 KG of 20% higher enriched uranium since May, its available “stockpile” of 20% remains almost unchanged in that time, a new UN atomic energy agency report finds. That’s because Iran has converted over half of its 20% stockpile for use in a medical reactor.

Those are among the mix of puzzling and concerning facts in the latest International Atomic Energy Agency (IAEA) report on Iran which show growing IAEA exasperation with Iranian stonewalling on granting inspectors access to a site where suspected military research occurred.

Iran has installed over a 1,000 more centrifuges in the fortified, underground Fordow enrichment facility near Qom–a doubling since May, the new IAEA report, released Thursday, found. But it does not appear that most of those centrifuges are yet operating. All the newly installed centrifuges are also of Iran’s first-generation, IR-1 model, less powerful than newer designs.

“Iran has not increased the number of centrifuge cascades producing 20 percent LEU at either” of its two enrichment sites, Fordow or Natanz, the Institute for Science and International Studies (ISIS) noted in an analysis of the new report..

As of August 2012, Iran has produced almost 190 KG of 20% enriched uranium since it began the higher level enrichment work in early 2011, the report says. However, Iran has converted over half of that total amount — about 98 KG — for use in fuel plates for a medical reactor, thus leaving only about 91 KG available that could be higher enriched to weapons grade. That represents almost no net gain in its 20% stockpile since May, arms control analysts noted.

“Although Iran has enriched additional uranium to almost 20%–a level that could be more quickly turned into weapons material–Tehran has converted much of this material to reactor fuel,” the Arms Control Association wrote in an analysis of the new IAEA report Thursday. “Thus Iran’s available stockpile of 20% enriched uranium (91 kg) is essentially unchanged from May.”

It would take about 200 KG of 20% enriched uranium to be higher enriched to “weapons grade’–90%  purity —to make enough fissile material for one nuclear bomb. However, Iran is unlikely to “break out” without enough fissile material to make two or more bombs, many  arms control experts believe.

Even if Iran may accumulate 200 KG of 20% enriched uranium, “this is only the first step to a nuclear weapon capability,” the Arms Control Association analysis continues. In addition, Iran would still need “time to produce the nuclear device itself (likely several months), which it has never done before, and then develop and probably explosively test a warhead that could fit on a ballistic missile, which would take still more time.”

What to make of the fact that there has been no net growth in Iran’s 20% stockpile since May? Is Iran demonstrating tacit restraint on the sensitive 20% front even while doubling the number of centrifuges installed, if not operating, at Fordo, to signal potential for further expanding enrichment? Is it some sort of signal from Iran towards potential flexibility on the 20% front?  (Former Iran nuclear negotiators Syed Hossein Mousavian has, for instance, proposed a “zero 20% stockpile” idea, under which there could be international supervision that Iran would produce only the amount of 20% it needs for medical purposes.)

“It is a plausible interpretation that there is a signal here,” George Perkovich, director of the nuclear policy program at the Carnegie Endowment for International Peace, told Al Monitor by email. “Nothing would be lost in seeking to explore it with the Iranians.  We needn’t guess: the involved states should try to find out.”

Other elements of the report document growing IAEA exasperation with Iranian run around and open defiance on one front. Continue reading →