Iran slows buildup of near-weapons-grade enriched uranium

Iran has significantly slowed the pace at which it is accumulating near weapons-grade enriched uranium and has diluted some of its stockpile, people briefed on the matter said on August 11, moves that could help ease tensions with the US and allow the resumption of broader talks over its controversial nuclear program.

The more slowly Tehran accumulates highly enriched uranium, the less potential fissile material it has for nuclear weapons, The Wall Street Journal reports. 

The news comes a day after Iran released four US citizens from prison into house arrest, the first step in a planned prisoner swap that Washington expects will eventually see them return home. If the US detainees are set free, Iran will gain access to billions of dollars of oil revenues trapped in South Korea under US sanctions.

US and European officials have told Iran that if there is de-escalation of tensions over the summer, they would be open to broader talks later this year, including on Iran’s nuclear program. 

For the Biden administration, the hope is to avoid any major crisis with Tehran in the lead-up to next year’s presidential elections. Critics in Washington and elsewhere say the US is preparing to reward Iran for taking US citizens hostage and for a minor pause in its nuclear work while Tehran ramps up regional threats and supplies military assistance to Russia for its war against Ukraine.

Since the US left the 2015 Iranian nuclear accord, which lifted international sanctions on Tehran in exchange for strict but temporary limitations on its nuclear work, Tehran has massively expanded its program. The Biden administration sought to revive the nuclear pact when it took office, but those talks broke down last year.

Among the most worrying parts of its work for Western officials is Tehran’s production of 60% enriched uranium, which US officials say could be turned into enough weapons-grade material for a nuclear bomb in less than two weeks. 

Moves appear intentional

US officials had hoped Tehran would stop accumulating 60% enriched uranium as one of a series of de-escalatory steps from both sides, which included the prisoners deal. 

According to the people, Iran has diluted a small amount of 60% enriched uranium in recent weeks and slowed the rate at which it is accumulating new material. Iran’s stockpile has grown since the 114 kilograms of highly enriched uranium Iran was recorded having in May, but it could easily dilute more of the 60% it has produced to get back to that level. It isn’t yet clear if Tehran plans to do that.

Iran was adding just short of 9 kilograms of 60% to its stockpile on average between February and May.

The United Nations atomic agency is expected to release its next report on Iran’s nuclear program in late August or early September.

While Iran’s production rate of enriched uranium can fluctuate for a number of technical reasons—including maintenance work at one of its two nuclear facilities—the fact that Iran has diluted some highly enriched uranium strongly suggests the slower accumulation of 60% material is intentional. 

Nonetheless, even if it does stop accumulating 60% material, Tehran has enough of the material for at least two nuclear bombs. US officials said this year Iran could field a nuclear weapon within several months.

Iran’s mission to the International Atomic Energy Agency didn’t immediately respond to a request for comment. Neither did the IAEA.

Following secret indirect talks this spring involving senior US and Iranian officials, Biden administration officials set out several steps they hoped Tehran would take to lower tensions. In addition to stopping the accumulation of 60% material, they said they hoped Iran would show better cooperation with the IAEA and stop attacks by Iran or its proxies on US forces and personnel.  

In exchange, Iran was set to win access to some $6 billion in energy-sales revenue frozen in South Korea and possibly, other moneys from the International Monetary Fund. 

Risk of delays

While the Biden administration has largely given up hopes of reviving the 2015 nuclear deal with Iran, US officials continue to say publicly they are seeking to avert a nuclear crisis through diplomacy. If the de-escalation effort bears fruit, the two sides could meet on the sidelines of the United Nations General Assembly in September and map out further talks.

This week’s release from jail of four American prisoners was the first step in a two-track plan, according to US and European officials. A fifth US citizen is under house arrest.

In a first stage, the diplomats said the American detainees would be released from prison in exchange for the transfer of up to $6 billion in Iranian oil revenue from South Korea to Switzerland, which represents US interests in Iran. As a second step, likely to take several weeks, the US citizens would be permitted to leave Iran once the Iranian money from South Korea reaches banks in Qatar, which Iran can access but Washington keeps under close watch.

US officials warned this week that they were still working on moving the South Korean funds and cautioned that the eventual release of the detainees could be delayed by disagreements in Tehran or the emergence of new flashpoints with Iran. 

US officials insisted that Iran would only be able to use the funds to buy food and medical goods for humanitarian purposes. Critics say the money would free up other Iranian government funds to be used for more nefarious purposes.

Just as the prisoner issue and the enrichment of near-weapons-grade material have started to move in the right direction, there have been no serious attacks on US forces in the region by Tehran or its proxies since late March when a US contractor was killed.

However in the last couple of weeks, the US has rushed planes, ships and Marines to the Gulf  because of the Iranian threat to shipping in the Gulf, an unusual and substantial deployment. 

“There is selective de-escalation in some areas and escalation in other areas and I think, in general, both sides are likely seeking a lowering of tensions but they have different definitions of the scope of de-escalation,” said Henry Rome, senior fellow at the Washington Institute for Near East Policy.