Iran has uranium to build nuclear bomb in 3-4 weeks and stockpiles are growing, UN says

World body also expressed concern Tehran is not providing credible answers on the origin of uranium particles found at three undeclared sites

New generation Iranian centrifuges on display for Iran's National Nuclear Energy Day in Tehran, in April 2021. Iranian Presidency Office / Wana

President Ebrahim Raisi, second right, is accompanied by Atomic Energy Organisation of Iran chief Mohammad Eslami, at Nuclear Technology Day in Tehran in April 2022. Iranian presidency / AFP

Mr Raisi and Mr Eslami at the April 2022 event. Iranian presidency / AFP

The Bushehr Nuclear Power Plant during a visit by Mr Raisi in October 2021. Iranian Presidency / AFP

Iran's Arak Heavy Water Reactor complex, south of the capital Tehran in January 2020. Maxar Technologies / AFP

A satellite image of Iran's Bushehr Nuclear Power Plant in January 2020. Maxar Technologies / AFP

A satellite image of Iran's underground Natanz nuclear site in May 2022. Planet Labs PBC / AP

A satellite image in January 2020 of Iran's Fordow Fuel Enrichment Plant, north-east of the city of Qom. Maxar Technologies / AFP

The Sanjarian nuclear centre, east of Tehran, in May 2021. Maxar Technologies / AFP

Iran has enough near weapons-grade uranium that it could build a nuclear bomb in three to four weeks with current stockpiles, a UN atomic energy agency report released on Wednesday said.

The milestone puts it way past the limits of the 2015 nuclear accord with world powers that limited Iran to possessing uranium enriched to only 3.67 per cent — down from the 20 per cent that it had at the time and well below the 90 per cent needed for weapons.

The US withdrawal from the deal under then-president Donald Trump and its reimposition of sanctions prompted Iran to breach the deal's nuclear restrictions.

The International Atomic Energy Agency's quarterly report to member states, seen by Reuters, said that Iran has increased its stockpiles of 60 per cent uranium hexafluoride — which can be enriched in a centrifuge — by 12.5 kilograms to 55.6kg.

“Iran now can produce 25kg [of uranium] at 90 per cent if they want to,” a senior diplomat said in response to Wednesday's report when asked if the country had enough material for a bomb.

It would take Iran about three to four weeks to produce enough material for a bomb if it wanted to, the diplomat said, and it would take the IAEA two to three days to detect a move in that direction.

Iran has long denied it is attempting to build a bomb and insists its nuclear activities are peaceful.

Indirect talks between Iran and the US have made only stuttering progress towards reviving the 2015 deal, which would take the many advanced centrifuges Tehran is now using offline, as the deal only allowed it to enrich with first-generation IR-1 centrifuges.

A revived deal would also slash its stocks of uranium enriched to various levels — currently about four tonnes — back to within the deal's cap of 202.8kg.

However, Iran's continued refusal to account for uranium particles found at three previously undeclared sites has become a major stumbling block to agreeing on a return to the deal.

Iran has demanded that the IAEA's years-long investigation into the discovery be scrapped while those in the international community have demanded answers.

The West has said that Iran, as a signatory of the nuclear Non-Proliferation Treaty, must clear the matter up and that it has nothing to do with the 2015 agreement.

“[IAEA Director General Rafael Grossi] is increasingly concerned that Iran has not engaged with the agency on the outstanding safeguard issues during this reporting period and, therefore, that there has been no progress towards resolving them,” a second agency report, also seen by Reuters, said.

US intelligence agencies and the IAEA believe Iran had a secret, co-ordinated nuclear weapons programme that it halted in 2003. Iran, however, insists it never had such a programme.

Most of the sites are thought to date back to about 2003 or earlier.

“The agency is not in a position to provide assurance that Iran's nuclear programme is exclusively peaceful,” the report said.

This means that without credible explanations from Iran on what happened to the uranium that appears to have been present at the three sites, the agency could not guarantee that material had not been syphoned off to make weapons.