The killing of Iranian nuclear scientists in US-Israeli military strikes has raised fears that, if the regime destabilizes, weak controls over uranium stockpiles and the proliferation of nuclear expertise will increase proliferation risks.
While Iran may replace its lost personnel, experts say it will be difficult to rebuild lost expertise and that unknown sites in the country could leave dangerous materials and knowledge vulnerable.
“Currently, the risk of nuclear terrorism or nuclear materials moving onto the black market is low,” said Kelsey Davenport, director of nonproliferation policy at the Arms Control Association.
“Non-state actors will face challenges accessing enriched uranium, and it is unlikely they will have the infrastructure to enrich it to weapons-grade levels and transform it into the metal needed for warhead cores,” she said.
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“However, if the current Iranian government implodes or the conflict leads to significant internal instability, the risk of nuclear material being stolen or diverted to undeclared sites is increased.”
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“There is also the danger that Iranian nuclear scientists may be willing to sell their expertise to state or non-state actors seeking nuclear weapons,” Davenport said in the new report.
Several senior figures in Iran’s nuclear and defense infrastructure have been killed in the past two years, along with a campaign of US and Israeli strikes on Iran’s nuclear facilities between 2025 and 2026.
Among them is Hossein Jabal Emelian, head of the Defense Innovation and Research Organization (SPND), who was killed in 2026 during Operation Rising Lion and Operation Epic Fury.
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The SPND is seen as the successor to Iran’s pre-2004 nuclear weapons program and plays an important role in new weapons research.
Others killed in 2025 include Mohammad Mehdi Tehranchi, Akbar Motalebizadeh and Said Borji, all of whom were linked to arms operations.
“The full impact of this campaign on Iran’s weaponization capabilities remains unclear,” Jim Lamson, a senior research associate at the Center for Nonproliferation Studies, told Fox News Digital.
“There will be replacements of managers and scientists, but it will be difficult to replace the impact on the experience and expertise of the officers who were killed,” said the former CIA analyst.
“Several key scientists involved in suspected weapons development killed in 2025 and 2026.”
“Their successors may also fear being targeted in the future, whether by military attack or assassination. This may affect their motivation and willingness to participate in any nuclear weapons program.”
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Lamson also said that many of those targeted were embedded in sensitive areas of Iran’s nuclear operations, including fuel cycles and weapons.
“These scientists had expertise in areas of the nuclear fuel cycle of major concern for nuclear weapons, including the production of highly enriched uranium (HEU), which was Iran’s main route for fissile material,” he said.
“The scientists also had expertise in weapon-making—that is, in key aspects of the design and production of nuclear explosive devices,” Lamson added.
U.S. and Israeli targeted strikes have also affected networks of sites related to their work, creating further obstacles to Iran’s program in the near term, he said.
“We have identified at least 11 weapons-related sites that have been hit since 2024,” Lamson said.
“These include the SPND headquarters, a newly identified site called Min-Zadaei in northeast Tehran, the SPND’s Taleghan and Sanjarian explosives test sites, the Ministry of Defense’s Shahid Mesami complex in western Tehran, and several research universities.”
These facilities were all involved in neutronics, explosives, metallurgy and nuclear physics — all linked to nuclear weapons development, he said.
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Despite the scale of the latest attack, Iran retains enriched nuclear material, with President Donald Trump saying on April 17 that the US would work with Iran to recover “nuclear dust” – enriched uranium – from the sites and that both countries would use heavy machinery to remove it.
The International Atomic Energy Agency also estimates that Iran has more than 200 kilograms of uranium enriched to 60 percent in Esfahan — enough for about five weapons if further enriched.
Iranian Foreign Minister Seyed Abbas Araghchi also said it was “under the rubble” of the previous attack and that Tehran had no plans to recover.
“It’s always possible that Iran has additional sites that Israel and the US were not aware of,” Lamson said.
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“We will have to wait and see how much these operations translate into a lasting strategic impact on Iran’s ability to produce nuclear weapons.”
“The damage and deaths from Israeli and US strikes are easy to identify, and difficult to assess their true impact on Iran’s ability and intent to develop nuclear weapons,” Lamson explained.
Original article source: Killed Iranian nuclear scientists raise threat over uranium, expertise finds its way onto the black market
