Iran’s Supreme Leader Ayatollah Ali Khamenei delivers a televised speech in Tehran, Iran, June 4, 2021. Photo: official handout via Reuters

Iran’s breakout time to produce enough fuel for a nuclear weapon has dropped to just 12 days, according to a new analysis of the latest reports by the International Atomic Energy Agency (IAEA), the United Nations’ nuclear watchdog.

The Institute for Science and International Security, a US-based think tank, on Friday released its assessment of a pair of IAEA reports on Iran showing that despite the Islamic Republic slowing its rate of production of highly enriched uranium and “downblending” some of its existing stockpiles to lower levels of purity, the time to breakout has actually shortened and may be harder to detect.

“Iran retains the ability, using 40 kilograms (kg) of 60 percent highly enriched uranium (HEU) and three or four advanced centrifuge cascades, to break out and produce enough weapon-grade enriched uranium for a nuclear weapon in 12 days,” the report says. “This breakout could be difficult for the IAEA to detect promptly, if Iran delayed inspectors’ access.”

That conclusion runs counter to the wishes of some Western diplomats who hoped the slowdown in Iran’s rate of enriching high-purity uranium might signal a “de-escalation” between the US and Iran over the latter’s nuclear program.

The new assessment’s findings are based on a pair of IAEA quarterly reports on Iran that the nuclear watchdog has distributed to member states, but that won’t be published until the agency meets later this month.

Uranium is considered “weapons grade” at 90 percent enrichment, but most experts argue there are few if any civilian purposes for uranium to be enriched beyond the three to five percent typically used in nuclear reactors.

The Institute for Science and International Security’s analysis describes how Iran could use its stockpiles to rapidly gather enough weapons-grade uranium to build more nuclear weapons faster than previous IAEA data showed.

“Using more of its remaining stock of 60 percent enriched uranium in the same three or four cascades, and its stock of near 20 percent enriched uranium in the vast bulk of its production-scale cascades, Iran could produce enough weapon-grade uranium (WGU) for an additional five nuclear weapons within the first month of a breakout, bringing the total to enough WGU for six nuclear weapons, or an increase of one since May 2023,” the analysis says. “Thus, Iran has increased its breakout capability, despite only a small increase in its 60 percent stock.”

Iran reportedly continues to grow its stock of uranium enriched up to 60 percent purity despite doing so at a slower pace.

According to Friday’s analysis, Iran could have enough uranium for 10 bombs in as little as four months based on the IAEA’s available data.