Assessing the damage to Iran’s nuclear programme

Israel’s military has said the current goal of its continuing campaign against Iran is the dismantling of Tehran’s nuclear and ballistic missile programmes.

Iran has been enriching uranium to up to 60% fissile purity, which could be refined further to the roughly 90% that is weapons-grade material.

The International Atomic Energy Agency (IAEA), which inspects Iran’s nuclear sites including its enrichment plants, says this is of “serious concern” because no other country has enriched to that level without producing nuclear weapons. Western powers say there is no civil justification for such high-level enrichment.

Tehran has long insisted its nuclear programme is for civilian purposes only and points to its right to nuclear technology for peaceful purposes, including enrichment, as a party to the nuclearNon-Proliferation Treaty.

Two of Iran’s main nuclear facilities have been badly damaged in Israeli air attacks:

The Fuel Enrichment Plant (FEP) at Natanz is a vast underground facility designed to house 50,000 centrifuges, the machines that enrich uranium.

There has long been speculation among military experts about whether Israeli airstrikes could destroy the FEP given that it is several floors underground.

There were about 17,000 centrifuges installed there at last count, of which around 13,500 were operating, refining uranium to up to 5%.

The electricity infrastructure at Natanz was destroyed by Israel, IAEA chief Rafael Grossi told the U.N. Security Council on Friday, specifically an electrical sub-station, the main electric power supply building, emergency power supply and back-up generators.

“With this sudden loss of external power, in great probability the centrifuges have been severely damaged if not destroyed altogether,” Grossitold the BBCon Monday.

The above-ground Pilot Fuel Enrichment Plant (PFEP) at Natanz is the smallest and softest target of Iran’s three enrichment plants and was destroyed in the Israeli attack, according to the IAEA. Long a research and development centre, it used fewer centrifuges than the other plants, often connected in smaller clusters of machines known as cascades. It did, however, have two interconnected, full-size cascades of up to 164 advanced centrifuges each, enriching uranium to up to 60%.

Israeli strikes damaged four buildings at the nuclear complex at Isfahan, the IAEA has said, including the Uranium Conversion Facility (UCF) and facilities where work on uranium metal was conducted.

While it has other uses, mastering uranium metal technology is an important step in making the core of a nuclear weapon. If Iran were to try to make a nuclear weapon, it would need to take weapons-grade uranium and turn it into uranium metal.

Uranium conversion is the process by which “yellowcake” uranium is turned into uranium hexafluoride, the feedstock for centrifuges, so that it can be enriched. If the UCF is out of use, Iran will eventually run out of uranium to enrich unless it finds an outside source of uranium hexafluoride.

Iran’s underground enrichment plant at Fordow

Iran’s most deeply buried enrichment installation at Fordow, dug deep into a mountain, has suffered little or no visible damage, the IAEA reiterated on Monday.

While Fordow has only about 2,000 centrifuges in operation, it produces the vast majority of Iran’s uranium enriched to up to 60%, using roughly the same number of centrifuges as Natanz, because it feeds uranium refined to up to 20% into those cascades, compared to 5% at Natanz.

Fordow produced 166.6 kg of uranium enriched to up to 60% in the most recent quarter. According to an IAEA yardstick, that is enough in principle, if enriched further, for just under four nuclear bombs, compared to the PFEP’s 19.2 kg, less than half a bomb’s worth.

In 2018, Israel obtained secret files from Iran’s nuclear archive revealing previously hidden details about the key underground facility.

In addition to attacks on nuclear facilities, at least 14 Iranian nuclear scientists have been killed in Israeli attacks since Friday, including in car bombings, two sources in the Gulf said on Sunday.

Israel’s armed forces named nine of them on Saturday, saying they “played a central part of the progress toward nuclear weapons” and that “their elimination represents a significant blow to the Iranian regime’s ability to acquire weapons of mass destruction”. That assertion could not immediately be verified.

Western powers have often said Iran’s nuclear advances provide it with an “irreversible knowledge gain”, suggesting that while losing experts or facilities may slow progress, the advances are permanent.