VIENNA (Reuters) – United Nations inspectors have found uranium particles enriched to a higher-than-expected level at an Iranian underground site where Tehran has installed more than 50 percent more enrichment centrifuges, a U.N. watchdog report said on Friday.
It said Iran had told the U.N. agency that the traces of highly refined uranium – at a level that could take Iran further down the road to potential weapons-grade threshold – “may happen for technical reasons beyond the operator’s control”.
“The Agency is assessing Iran’s explanation and has requested further details,” the International Atomic Energy Agency (IAEA) report said.
The IAEA report said environmental samples taken in February at Iran’s Fordow facility – buried deep beneath rock and soil to protect it from air strikes – showed the presence of particles with enrichment levels of up to 27 percent.
That takes it across the line from low-enriched to high-enriched uranium.
It is “significantly” above the threshold level, one diplomat familiar with the issue said, adding that a “number” of such particles had been discovered and that further samples were taken earlier this month to see whether the find was confirmed.
The quarterly IAEA report was issued to member states a day after six world powers – the United States, Russia, Britain, Germany, China and France – failed to convince Iran to halt its 20 percent enrichment during a May 23-24 meeting in Baghdad.
Iran started enriching to this level in 2010 and has since sharply expanded the activity, saying the material will serve as fuel for a medical reactor. But a suspicious West is alarmed since such enhanced enrichment accomplishes much of the technical leap towards 90 percent – or weapons-grade – uranium.
Iran has increased its stockpile of 20 percent uranium to around 145 kg in May from nearly 110 kg some three months ago, the report said. Western experts say about 250 kg is needed for a nuclear bomb, if processed further.
The report also showed Iran had installed 368 enrichment centrifuges at Fordow facility in addition to the 696 already operating there.
Although not yet being fed with uranium, the new machines could be used to further expand Iran’s output of uranium enriched to a fissile concentration of 20 percent, the part of the country’s nuclear programme that most worries the West.
U.S. proliferation expert David Albright said he believed it was a production error that caused the higher-enriched uranium trace at Fordow. “Nonetheless, (it is) embarrassing for Iran,” Albright said.
He said the centrifuge cascades – interlinked networks of enrichment machines – at Fordow had 17 stages instead of 15 as in the old design.
“An effect is to overshoot 20 percent when 3.5 percent LEU (low-enriched uranium) is fed into the tandem cascades at the rate used for the 15-stage cascade,” he said.
But, “this process of moving to 17 stages also reflects a reconfiguration of the cascades that can make (a nuclear weapons) breakout easier,” Albright added.
Enriched uranium can be used to fuel power plants, which is Iran’s stated purpose, or provide material for bombs, if refined to a much higher degree, which the West suspects may be Iran’s ultimate goal. The Islamic Republic denies that.
The U.N. agency also said satellite images showed “extensive activities” at the Parchin military complex, southeast of Tehran, which inspectors want to check over suspicions that nuclear weapons-relevant research was done there.
The “activities” could hamper the IAEA’s inquiry, it said – an allusion to what Western diplomats have said may be Iranian efforts to remove incriminating evidence. Iran has denied pursuing a clear weapons capability there or anywhere else.
The IAEA told Iran in a letter sent this month that it needed “early access” to Parchin, the report said. Iran has repeatedly refused this, maintaining that Parchin is a solely conventional military base beyond the writ of inspectors.
The IAEA said it had urged Iran to expedite a final agreement to enable inspectors to resume their long-running investigation into suspected nuclear explosive experiments.
IAEA chief Yukiya Amano had said earlier this week after talks in Tehran that the two sides were close to such a deal although “some differences” remained before it could be sealed.
(Reporting by Fredrik Dahl; Editing by Jon Hemming)