Natanz nuclear plant
Natanz nuclear plantReuters

Iran is pressing ahead with its rollout of an upgrade to its advanced uranium enrichment program, a report by the UN nuclear watchdog seen by Reuters on Monday showed.

The first of three cascades, or clusters, of advanced IR-6 centrifuges recently installed at the underground Fuel Enrichment Plant (FEP) at Natanz is now enriching, said the report by the International Atomic Energy Agency (IAEA).

Diplomats say the IR-6 is its most advanced model, far more efficient than the first-generation IR-1 - the only one the deal lets it enrich with.

In the confidential report to UN member states, the IAEA wrote, according to Reuters, "On 28 August 2022, the Agency verified at FEP that Iran was feeding UF6 enriched up to 2% U-235 into the IR-6 cascade ... for the production of UF6 enriched up to 5% U-235."

Uranium hexafluoride (UF6) is the gas centrifuges enrich.

Of the two other IR-6 cascades installed at the Natanz FEP, one was undergoing passivation with depleted UF6, a process that is carried out before enrichment proper begins, and the other had yet to be fed with any nuclear material, the agency said.

The report comes as Iran and the US appear closer to reaching an agreement to revive the 2015 nuclear deal, from which former US President Donald Trump withdrew in 2018.

Iran recently sent its proposals over the final draft sent on August 8 by the EU, which has coordinated talks in Vienna on reviving the pact.

The proposal, submitted on July 26 by EU foreign policy chief Josep Borrell, has been described by the EU as a “final draft” of the agreement.

Last Wednesday, Iran confirmed it had received a response from the United States to its proposals on the EU draft, saying it is “carefully reviewing the US opinions”.

On Sunday, White House National Security Council spokesperson John Kirby said that an agreement on a return to the Iran nuclear deal is closer, but there are still some issues to be ironed out.

"We are certainly closer today than we were about two weeks ago thanks to Iran being willing to concede on a couple of major issues," Kirby told CNN in an interview, before adding, "There are still gaps that remain between all sides."

“We’re hoping for a positive outcome because no problem in the Middle East is easy to solve with a nuclear-armed Iran,” he continued, stressing that President Joe Biden “still believes that diplomacy and a return to the nuclear deal are the best possible outcome, and we’re going to keep working on that.”

Earlier this month, the IAEA released a report saying that Iran has completed installing three advanced IR-6 centrifuge cascades at its Natanz fuel enrichment plant.

Last month, the IAEA issued a report in which it said Iran is escalating its uranium enrichment further by preparing to use advanced IR-6 centrifuges at its underground Fordow site that can more easily switch between enrichment levels.