(Iraqi yellowcake anyone?)
Confusion on whether Iran truly needed only “
” to make a nuclear weapon, as President Donald Trump suggested on Monday, hangs over
on the Persian Gulf nation. Nuclear experts call this claim unlikely—but the confusion may stem from some basics of atomic chemistry.
“There was no evidence that Iran was close to a nuclear weapon,” says
of the James Martin Center for Nonproliferation Studies at the
. His comment echoed those of
after the war’s start, as well as statements from International Atomic Energy Agency (IAEA) chief
at that time and
and last year’s “
” report by U.S. intelligence agencies.
According to an IAEA
, as of June 2025, Iran possessed 441 kilograms of 60 percent enriched uranium, where the percentage refers to the share of the isotope uranium 235 (U 235) found in the material. That would be enough for 10 nuclear weapons if the material could be enriched further to full 90 percent weapons-grade concentrations, according to the IAEA. That further enrichment would take a matter of
in a fully functioning Iranian
, perhaps explaining the time line within Trump’s declaration.
That step alone doesn’t equal a bomb, however. And Iran’s main enrichment capabilities were “completely and
,” according to Trump himself in June, after the U.S.
. The administration’s special envoy to the Middle East
nonetheless claimed on March 3, after the start of the current war, that Iran had the capability to make 11 nuclear bombs. Trump administration officials
to include nuclear technical experts in their negotiation teams with Iran prior to the war, adding to the uncertainty. If Iran really had rebuilt these facilities, that might have led—over months and not weeks—to the nation resuming its uranium enrichment, Lewis says. “But this is all ‘if,’ ‘maybe’ and ‘later,’” he adds.