The International Atomic Energy Agency (IAEA) found that all of Iran’s 8,426 centrifuges dedicated to enriching uranium to 3.5 percent purity were idle during a visit on Nov. 16. Earlier in the month it found 4,816 of them spinning, and on Monday Iran informed the IAEA that some 4,600 were working again.
The IAEA gave no explanation for the temporary halt in its quarterly report on Iran, though Western diplomats and a former top IAEA official have suggested in recent days that long-standing technical problems may have come to a head.
Iran denies any technical difficulties, and Iranian officials claim to have blocked any impact from the Stuxnet computer worm, which Western security and nuclear analysts suggested last week had been designed to impede the supersonic spinning speeds of centrifuges, causing some to spin out of control.
“[Westerners] angrily disclosed the issue [of Stuxnet] when they did not obtain their goals,” Mr. Salehi was quoted saying by Iranian media Tuesday. “This shows that Iranian scientists and engineers are pressing ahead with complete vigilance.”
UN Security Council resolutions require Iran to stop all enrichment work until it resolves outstanding questions about the peaceful nature of its nuclear program. Iran is meant to sit down with the US and other world powers for long-delayed nuclear talks on Dec. 5.
The IAEA reported that no declared nuclear material had been diverted. It calculated that Iran had, by the end of October, produced a total of 3,183 kilograms of 3.5 percent uranium – enough for more than two nuclear weapons if enriched to above 90 percent.
The use of Iran’s two growing stockpiles are likely to be a top priority at upcoming talks, though some Iranian officials have stated that nuclear issues would not be discussed.
Both Iran and world powers have so far dismissed two separate fuel-swap deals, in which Iran would exchange a portion of its homemade enriched uranium for fuel plates it needs for a small, decades-old reactor in Tehran.
In its report, the IAEA said it received only limited cooperation from Iran, was restricted from certain facilities, and expected design data that it said was required under Iran’s safeguards agreement – but which Iran maintains it does not need to provide.
The IAEA said that Iran still had to explain designs about possible military efforts, including a missile warhead. Iran says the designs are forgeries.
“The passage of time and the possible deterioration in the availability of some relevant information increase the urgency of this matter,” the report said. “Iran’s substantive and proactive engagement is essential….”
Iran operates centrifuges with a decades-old design, originally Dutch and sold by Pakistan. Mr. Heinonen noted that Iran had been operating them at low capacity for many months. “This indicates there is a problem,” he said.