The paper, obtained by Reuters, also said Tehran had started up more than 1,300 centrifuge machines, divided into eight cascades, or networks, in the Natanz complex, in an accelerating campaign to lay a basis for “industrial scale” enrichment.
Both moves flew in the face of U.N. Security Council resolutions demanding that Iran stop enriching uranium over fears Tehran’s professed civilian nuclear fuel program is a cover for mastering the means to build atomic bombs.
Tehran says it seeks only nuclear-generated electricity. But its past concealment of sensitive enrichment research from the International Atomic Energy Agency and continued stonewalling of IAEA inquiries have shaken confidence in its intentions.
Iran announced on April 9 that it had begun enriching in the Natanz hall, ramping up from a limited research operation above ground. But diplomats treated the disclosure skeptically pending word from the watchdog International Atomic Energy Agency.
To that end, the document said, IAEA inspectors conducted a “design information verification” at the plant on April 15-16 and were informed that eight cascades — 1,312 centrifuges in all — were running and “some” uranium was being fed into them.
The three-paragraph note by IAEA deputy director Olli Heinonen also said Iran had stopped letting inspectors verify design work at the Arak heavy water reactor, under construction and due for start-up in 2009.
PROLIFERATION RISK
Major powers see the reactor as a nuclear proliferation risk as it could be used to produce plutonium for the core of nuclear bombs, although Iran says it has only peaceful purposes such as production of radio-isotopes for medical care.
Iran blocked IAEA access to Arak under its decision a few weeks ago to stop giving inspectors early design detail on future nuclear facilities. The move retaliated for a March U.N. resolution widening sanctions on Iran over its nuclear defiance.
In his letter to Iran’s IAEA envoy, Heinonen indicated that Tehran was not living up to transparency commitments by refusing to allow short-notice inspectors or camera surveillance at Natanz and restricting access to Arak.
Iran says such steps are not covered by its basic safeguards agreement with the IAEA and it is not legally bound to them.
Heinonen urged Iran to “reconsider” its reduction of cooperation with the IAEA to a legal minimum, well below what the agency sees as essential to clearing up longstanding questions about the nature of the Iranian nuclear program.
Tehran vowed on Tuesday to pursue plans to heighten its uranium enrichment capacity and said U.N. sanctions would not hamper centrifuge installation in the Natanz complex, flanked by anti-aircraft guns against feared U.S. attack.
Iran’s Atomic Energy Organization chief suggested it could take 2-4 years to reach the goal of 50,000 centrifuges. Another senior official said Iran had assembled 3,000 centrifuges so far. Iran aims to have 3,000 up and running by next month.
That could be enough to refine uranium for one bomb within a year, if Iran wanted to and if the machines ran for long periods without breakdown — a proficiency Iran has yet to demonstrate.
Centrifuges spin at supersonic speed to produce fuel for power plants or, if enriched to high levels, warheads.
The United Nations Security Council has passed two sanctions resolutions on Iran since December, targeting its nuclear and military sectors and severely impeding its financial transactions with the outside world.
Iran’s April 9 announcement that industrial-scale nuclear fuel production had begun elicited a warning from the United States that Tehran could be hit with harsher sanctions.
