VIENNA (Dispatches) -- Iran has finished moving a first cascade of advanced centrifuges from an above-ground plant at its main uranium enrichment site to an underground one, a UN atomic agency report has said.
The transfer to the underground plant apparently built to withstand aerial bombardment was done in response to the burning down of an above-ground centrifuge-building workshop at Natanz in July, which Tehran has called an act of sabotage.
The move was the latest of scaling back of commitments by Iran of its 2015 deal with major powers in response to Washington’s 2018 withdrawal from the landmark accord and its reimposition of sanctions against Tehran. The deal says the underground plant at Natanz can only be used for first-generation IR-1 machines.
"They finished installing one of the three cascades and they have started installing a second cascade,” a senior diplomat quoted by Reuters said, adding that while they were being moved, these more efficient and productive machines were not operating as yet.
A cascade is an interlinked cluster of centrifuge machines.
Iran’s stock of low-enriched uranium is now far above the deal’s 202.8 kg limit at 2.4 tonnes, but it produced 337.5 kg in the quarter, less than the more than 500 kg recorded in the previous two quarters by the International Atomic Energy Agency.
Iran had previously informed the IAEA that it would transfer three cascades of advanced centrifuges at Natanz underground. The first, of IR-2m machines, is installed and connected but has not been fed with uranium hexafluoride gas, the feedstock for centrifuges, according to the report, obtained by Reuters.
The Islamic Republic has started installing a cascade of IR-4 machines in the underground plant but not the third cascade of IR-6 ones, the report said.
Iran has told the agency that it aims eventually to "concentrate” all its enrichment research and development - a term usually reserved for advanced centrifuges - in the area of the underground enrichment plant, the report said.
The US special representative for Iran insisted Thursday that a pressure campaign of sanctions targeting Iran would persist into the administration of Joe Biden, even as the president-elect has pledged to potentially return America to Tehran’s nuclear deal with world powers.
Elliot Abrams, who also serves as the U.S. special representative to Venezuela, said sanctions targeting Iran would go on. That, as well as continued scrutiny by United Nations inspectors and American partners in the Mideast, would maintain that pressure, he said.
Alireza Miryousefi, a spokesman for Iran’s mission to the UN, dismissed Abram’s comments.
"The policy of maximum pressure and sanctions against Iran has failed,” Miryousefi told the AP. "The U.S. effort to abuse this corrupt policy is futile and will only lead to further isolation of the U.S. on the international stage.”
Abrams replaced Brian Hook as America’s envoy on Iran, who announced he’d leave his post in August after serving as the face of Trump’s maximum-pressure campaign. That effort has floundered internationally as the U.S. failed to convince the UN to stop an arms embargo on Iran from expiring in October.
Iran is enriching uranium to as much as 4.5% purity, higher than allowed under the accord. Tehran abandoned all limits on its enrichment months after Trump’s pullout from the agreement.
Abrams described Iran’s construction at its underground Natanz enrichment site as "another Iranian challenge” to the International Atomic Energy Agency.
Iran long has insisted its nuclear program is for peaceful purposes.