Nuclear Dust—What is it and can Trump take it from Iran?

President Donald Trump has repeatedly threatened to send U.S. forces deep into Iran to retrieve the “nuclear dust” from uranium storage sites deep underground, referencing the radioactive material Washington fears Tehran could use to make nuclear weapons.

Who ends up controlling Iran’s stockpiles of highly enriched uranium has been one of the biggest sticking points in U.S. negotiations with Iran for years.

Trump has at once said the U.S. will get hold of the “nuclear dust” one way or another while acknowledging on Monday it would be a “long and difficult process.”

Military experts say any operation to pull Iran’s highly enriched uranium would be nearly impossible to do without Iran’s help.

So, why is it such a key issue for both Iran and the U.S., and the issue that could unlock an end to the war?

What is Nuclear Dust?

“Nuclear dust” appears to be Trump’s favored way of referring to stockpiles of highly enriched uranium, which international experts say Tehran has hidden away deep underground under at least one of the sites bombed by the U.S. last June.

Highly enriched uranium can be made into metal, then used to build nuclear weapons.

Iran’s cache of highly enriched uranium has given Tehran’s leadership the option to weaponize its nuclear material, and is a bargaining chip against the U.S.

The United Nations’ nuclear watchdog, the International Atomic Energy Agency (IAEA), said that by mid-2025, Iran had enriched roughly 440 kilograms of uranium to 60 percent, which is close to weapons-grade. From there, it’s a short scientific jump to making a powerful nuclear bomb.

Iran has long said its nuclear program is peaceful, geared up to generate energy for a civilian population using an increasing amount of electricity.

But it’s generally accepted that uranium enriched to 3.67 percent works for civilian reactors, and Iran has enriched uranium between 20 and 60 percent.

A now-defunct agreement from 2015, known as the Joint Comprehensive Plan of Action (JCPOA) or informally as the Iran nuclear deal, limited Iran’s enrichment to 3.67 percent.

However, Iran has openly said it has abandoned parts of the JCPOA since Trump pulled the U.S. out of the deal during his first time in office. Trump had heavily criticized the deal, agreed under former U.S. President Barack Obama.

The U.S. government said it strikes during the 12-day war between Israel and Iran in June 2025 — known as Operation Midnight Hammer — “obliterated” Iran’s nuclear facilities in Isfahan, Fordow and Natanz . Trump said “monumental damage” was done to “all” nuclear sites in Iran.

But since then, many have questioned the extent of the damage to the Iranian sites.

Iran’s highly enriched uranium is still unaccounted for, although U.N. experts say to be at the central Iranian nuclear site of Isfahan. Trump has said the U.S. is aware of where the uranium stockpiles are, constantly watching through satellites.

The U.S. and Israel justified the joint strikes on Iran from February 28 as necessary to take out Tehran’s ability to make a nuclear weapon.

Trump, announcing the opening salvo, said Iran had “attempted to rebuild their nuclear program” following last year’s attacks. The IAEA said in March Iran did have an “ambitious” nuclear program but there was no evidence of a “structured” effort to build nuclear weapons.

In the wake of the American strikes — which included the first combat use of the 30,000-lb GBU-57 “bunker buster” bombs — pulling the “nuclear dust” from the Iranian sites is a tall order, Trump said on Monday.

Trump’s language is vague, but “nuclear dust” likely refers to uranium hexafluoride gas, which is put into centrifuges and spun at close to the speed of sound to separate out the material used to make nuclear bombs, William Alberque, a former director of NATO’s Arms Control, Disarmament and Weapons of Mass Destruction Non-Proliferation Center, told Newsweek.

It’s not clear whether Trump is calling the nuclear material “dust” in a reference to the destruction wrought on the nuclear sites, the physical state of the highly enriched uranium or alluding to damage to storage containers.

Uranium hexafluoride can be transported as a liquid or gas, but to turn it into a weapon, the enriched uranium must first become solid. It is converted into uranium salts and then into metal at specialized sites, like Isfahan.

Isfahan is where Iran has been turning uranium hexafluoride gas into solid and then metal, Alberque added. The metal can then be used to build the core in nuclear weapons.

Iran has moved containers of uranium from its nuclear enrichment sites at Natanz and Fordow toward its Isfahan facility for years, experts say. All three were hit by U.S. strikes last year but have not been the target of heavy bombardment in the last eight weeks.

Iran will have transported most of its enriched uranium to the laboratories underneath Isfahan in containers holding between 25 and 45 kilograms of the gas, Alberque said

How Could the US Extract It?

If the U.S. did try to extract highly enriched uranium from Iran, it would be a complicated and likely drawn-out operation, not least because it would be extremely difficult do without Iran’s agreement.

Without it, the U.S. would be under attack by Iran the whole time, said Frank Rose, who served as principal deputy administrator for the U.S. National Nuclear Security Administration (NNSA), told Newsweek.

They would have to establish control over the Isfahan site through a military operation, using tens of thousands of soldiers to then set up a corridor where the extracting team could bring in bulldozers.

Trump has nodded to these concerns. He told Reuters last week the U.S. and Iran would work “together” to pull the uranium from the ground at a “nice, leisurely pace” with the help of heavy machinery.

The entire process of securing, locating and extracting the material could take months, around 15,000 troops and several C-130 transport aircraft, Rose said.

“It’s not a one-week mission,” Rose said.

First, excavators would need to open up the tunnel entrances collapsed by U.S. and Israeli attacks, and geologists would then assess whether the tunnels could fall in, said Alberque.

The next task would be to locate the highly enriched uranium and ensure the containers are structurally sound, he said. If not, the material would have to be transferred to new canisters before being loaded up onto pallets and whisked away on cargo planes, Alberque added.

The U.S. likely wouldn’t transport the uranium in solid form, as converting gas to solid requires a specialized facility, like the one the U.S. and Israel have already destroyed at Isfahan.

The containers would likely be transported by land to an airstrip, where it would be flown out of Iran.

It’s not clear how close this airstrip would be to the excavation site.

While the Department of Energy, which oversees the NNSA, and the Pentagon do have protocols for this type of mission, it is still challenging.

Key To Negotiations

Despite the U.S. and Israeli attacks on nuclear sites and senior scientists, Iran could still continue to enrich uranium and resurrect the burgeoning program it built when the JCPOA disintegrated.

Experts have no up-to-date information on Iran’s most advanced centrifuges after Iran cut off sharing this data in 2022, Alberque said.

“They could have thousands ready to reconstitute the program at a moment’s notice,” he added.

On top of this, there is no firm guarantee that all the material extracted would be the sum of Iran’s uranium, Rose remarked.

As it is, Iran has not shown any public signs of giving up its nuclear program, keeping the U.S. on the hook and under pressure with its blockade of the vital Strait of Hormuz trade route.

The U.S. has been so far unsuccessful in its attempts to force Iran to relinquish its hold on the waterway, which typically sees a fifth of the world’s oil and gas, while fuel prices have yo-yoed since late February.

The U.S. has put a competing blockade in place to try to pressure Iran ahead of talks that were planned for early this week in Pakistan but failed to materialize.

Trump said on Tuesday he would extend a ceasefire between the U.S. and Iran — scheduled to expire on Wednesday — until progress is made on a peace proposal.

One idea thought to be on the table is that the U.S. may release $20 billion in frozen Iranian funds if Tehran agrees to give up its highly enriched uranium.

Trump claimed last week that Iran has “agreed to give us back the nuclear dust that’s way underground,” which Iran has not confirmed.

For the moment, Iran is still insisting its nuclear stockpile will stay on — or under — Iranian soil. The highly enriched uranium is not going “anywhere,” Tehran’s foreign ministry said last week.