On October 26 2024, the day after Israel conducted a massive counterstrike against Iranian missile and military sites, open-source sleuths noticed something strange: A building was unexpectedly missing within Iran’s Parchin military complex.
The relatively small, 40-meter-long building, known as Taleghan 2, was located southwest of several destroyed Iranian missile facilities — and happened to be used for experiments during Iran’s pre-2004 nuclear weapons program.
The site’s demolishment raised numerous questions. Did Israel violate US President Joe Biden’s warning to refrain from striking Iranian nuclear sites during its counterattack, which came in response to an October 1 Iranian missile barrage?
Moreover, what was Jerusalem’s motivation in destroying the facility? Had the Islamic Republic carried out new nuclear-weapons work at the site? Or was this a message to avoid such work or further attacks on Israel, lest the regime lose more meaningful nuclear sites?
A less pondered question is why the UN nuclear watchdog, the International Atomic Energy Agency (IAEA), had never visited the site, despite investigating a nearby sister building, Taleghan 1, in 2015. IAEA Director General Rafael Grossi declined to protest Israel’s strike on Taleghan 2 since the facility was not subject to IAEA monitoring.
Since Israel successfully destroyed most Iranian air defenses during the October 25 strike, Iran’s nuclear sites are now sitting ducks for additional Israeli attacks, perhaps with the blessing and even assistance from an incoming President Donald Trump.
Above all, the Taleghan 2 incident clearly shows how numerous policies have failed to restrain Iran’s nuclear threat, including two decades of diplomacy, periodic sanctions, IAEA investigations, and Western and Israeli assassinations and sabotage.
Given Tehran’s galloping nuclear progress during the Biden administration’s term, Jerusalem and Washington now have a narrowing window to eliminate the nuclear threat from their mutual arch-nemesis.
How the two nations proceed in the coming months could reshape Middle East security for decades to come.
A Large Crater
That Taleghan 2 was intact prior to the Israeli strike is certain.
But satellite imagery acquired by the Washington, DC-based Institute for Science and International Security, dated October 27, indicated that a large crater had replaced most of the building.
Prior to 2004, inside the building, Tehran had carried out tests related to initiating high explosives that would compress an atomic core to set off a nuclear blast.
So much is now known about the building and Iran’s nuclear weapons program, then titled the Amad Plan, thanks to the Israeli Mossad’s 2018 seizure of an archive of documentation from a Tehran warehouse detailing the regime’s work on nuclear weapons. The Israeli spies smuggled the documents back to Israel for analysis.
The archive materials indicated that in mid-2003, Tehran — facing exposure of its secret nuclear sites and activities, sustaining prodigious international pressure, and fearing US military action after America’s invasion of Iraq — opted to temporarily discontinue its plan to build nuclear weapons. Instead, Tehran planned to continue related nuclear work at a lower level and progress it for a later date.
Iran’s own photographs from inside Taleghan 2 showed that a small metal chamber was once present, along with equipment to model and take photos of the functions of a so-called multipoint initiation (MPI) system. The MPI, in Tehran’s nuclear-weapon design, sets off a uniform inward explosion. It compresses a uranium-metal core and neutron initiator, the latter comprised of material that starts a chain reaction to initiate a nuclear explosion.
What had become of the equipment at Taleghan 2? Was it still present at the site during Israel’s strike?
Iran, meanwhile, remained silent on the matter.
Then an Axios bombshell on November 15 confirmed, according to several former and current US and Israeli officials, that Israel had struck Taleghan 2 to disrupt new Iranian weaponization work. “They conducted scientific activity that could lay the ground for the production of a nuclear weapon,” a US official said. “It was a top secret thing. A small part of the Iranian government knew about this, but most of the Iranian government didn’t.”
Axios also noted that a US official said that “there was concern across the board” about the activity at Taleghan 2 facility.
While the Axios report focused on Iran’s renewed work on explosives, or the MPI, it remained unclear if some other, unknown effort had motivated the strike.
Israeli officials told Axios in a follow-up report that the destruction of the equipment inside Taleghan 2 created a “bottleneck” that Tehran would need to overcome to successfully build nuclear weapons. Moreover, the Israelis believed they could detect required foreign procurements.
All of this raised a question that had been lingering since early 2024: Had Tehran’s later date to construct nuclear weapons finally come?
No Access to Military Sites
In 2002, non-governmental groups and the media exposed Iranian covert nuclear sites and activities, prompting the IAEA to investigate and apply international monitoring. Likely understanding it was in a corner, Tehran complied — but only so much.
The regime kept most of its nuclear weapons work secret, revealing some efforts to the agency, but largely prolonging a wild goose chase that would span more than two decades and continue to this day.
After enacting broad sanctions on Iran starting in 2006, the P5+1 — the United States, France, United Kingdom, Germany, China, and Russia — reached a nuclear deal with Tehran in 2015 that granted temporary restrictions on Iran’s nuclear program in return for massive sanctions relief. Yet the accord, formally known as the Joint Comprehensive Plan of Action (JCPOA), did not require Iran to open its program to intrusive IAEA inspections, including checks at military sites that might conduct secret, ongoing nuclear weapons work. In fact, the deal never required the IAEA to determine whether Tehran’s program was theretofore devoted to peaceful use.
Instead, the deal required the IAEA to issue a “final” report on Iran’s nuclear weapons activities. But Iran refused to cooperate, providing false explanations and denials of its past work.
A side agreement between Iran and the IAEA accompanying the JCPOA required the regime to submit to a sole IAEA visit at the Taleghan 1 site. In reality, the visit appeared to check a box for Obama administration officials, who had promised a deal facilitating regular IAEA access to Iranian military sites.
The IAEA had acquired evidence from IAEA member states that, starting around 2000, Tehran had worked on high-explosive “hydrodynamic” tests — compression of the nuclear core to trigger a chain reaction — at Taleghan 1. Iran’s nuclear archive later confirmed that Tehran was testing the functionality of the center of its nuclear weapon, a neutron initiator, in a larger high-explosive chamber than the one inside Taleghan 2, which is located around the corner from Taleghan 1.
Iran refused IAEA access to Taleghan 1 in 2012, with Tehran stating it “was not able to grant access to that site.” Later that year, the IAEA observed the regime undertaking sanitization activities at the site, including removing earth — a hallmark of Iranian efforts to stymie IAEA environmental sampling for nuclear material.
The 2015 side agreement required Iran — rather than the IAEA — to take its own environmental samples from inside the Taleghan 1 chamber with IAEA inspectors nearby, an unprecedented arrangement that flew in the face of all prior standard IAEA practice. Yet samples could still reveal nuclear particles that would tell a forensic story about Tehran’s previous activities at the site.
Prior to the IAEA’s visit, Iran again carried out sanitization activities at Taleghan 1. Commercial satellite imagery showed Tehran concealing activities and carting something away.
When the IAEA finally visited Taleghan 1 in September 2015, the fabled high-explosive chamber was gone. But the agency still obtained damning evidence from Iran’s self-taken samples. Two particles of natural uranium — both man-made — indicated that Iran may have worked with this surrogate material for weapons-grade uranium to test the functions of the center of its nuclear weapon, the neutron initiator.
Tehran issued denials, which the IAEA reported were “not credible.” Yet the P5+1 implemented the JCPOA in early 2016, providing robust sanctions relief to Iran rather than requiring full IAEA access to any site to determine whether such activities had stopped.
Even though first-term President Trump exited the JCPOA in May 2018, Iran had again succeeded in maintaining its nuclear secrets. Under President Biden, who removed economic pressure the Trump administration had put in place, Tehran’s program expanded to alarming levels.
IAEA Never Went to Taleghan 2
The IAEA never visited Taleghan 2, nor did it go to other Amad Plan sites in the same vicinity, among numerous related sites located elsewhere.
Former IAEA Directors General Mohamed El Baradei and Yukiya Amano — the latter in office during the JCPOA’s finalization in 2015 and facilitated the Iran-IAEA side deal for access to Taleghan 1 — likely made these calls. Tehran had drawn red lines rejecting any IAEA investigation of its past, and the agency, the Obama administration, and Europe accepted this, even if it meant accepting a level of uncertainty about the future.
Olli Heinonen, deputy director for safeguards at the IAEA from 2005 until 2010 and a current distinguished fellow at the Stimson Center, said in a private communication that he could not understand why the IAEA in 2015 “did not see reasons at that time to visit Taleghan 2,” which “appeared to be functionally related” to Taleghan 1.
Heinonen said that “according to the usual IAEA verification practices,” the discovery of uranium particles at Taleghan 1 “warranted follow-up IAEA visits” to Taleghan 2.
Heinonen noted that when Israel provided the IAEA with a copy of Iran’s nuclear archive in 2018, “It was even harder to understand after studying the archives […] and findings in the first building that no IAEA visit was requested.”
Grossi, who assumed the position of IAEA director general in 2019, appeared not to fully know about the activities Iran carried out at Taleghan 2 when questioned during a November 2024 press conference. Grossi said, “We do not consider this a nuclear facility. We don’t have any information that would confirm presence of nuclear material there.”
Grossi did state that Israel should follow “a body of law” that “indicates that nuclear facilities should not be attacked.” Yet he also stated that while Israel may have information that Iran was carrying out concerning work at Taleghan 2, the IAEA does not, allowing Jerusalem to dodge international scrutiny — at least for now.
Grossi may have inadvertently paved the way for more strikes.
More Strikes to Come?
How will the Taleghan 2 incident play out in the months ahead?
Iran, for its part, busily cleaned and removed debris from the site days after the strike. It has not yet acted on threats to retaliate against the Jewish state once more.
The regime’s air defenses remain decimated since the Israeli strike, with no likelihood that Tehran can rebuild for months to come. This renders key nuclear facilities — the uranium-producing enrichment plants at Natanz and Fordow and the uranium conversion facility at Esfahan — particularly exposed and vulnerable.
Those plants have now churned out enough highly enriched uranium for Iran to make weapons-grade material for up to 16 nuclear bombs in five months, with additional months needed to weaponize the fuel for atomic devices.
The US and Israeli intelligence communities also remain concerned that Iran has taken initial steps toward weaponization. The United States reportedly warned Tehran in June to stop such activities, and the Office of the Director of National Intelligence reported its concerns to Congress soon after.
The Taleghan 2 episode may provide new confirmation of Iran’s weaponization activities.
President-elect Trump said in October that Biden should have urged Israel to strike Iran’s nuclear facilities. Yet Trump has also said he seeks to avert additional regional conflicts and would negotiate with the regime. However, given Trump’s shocking order to assassinate Tehran’s Quds Force chief Qassem Soleimani in 2020, Iran cannot be certain Trump would not approve or assist an Israeli strike.
Fear of detection and joint US-Israeli military strikes may cause Tehran to think twice in seeking to weaponize its nuclear capabilities.
Still, even if Iran presses ahead with weaponization, military strikes on Iran’s program are no small feat. To be fully successful at destroying, rather than just damaging, the facilities, Israeli military capabilities may be inadequate. Rather, full success requires a joint US-Israeli bombing campaign lasting many days or weeks, and a steady effort to prevent Tehran’s nuclear reconstitution. These difficulties explain why Jerusalem and Washington have never acted.
Yet Iran’s growing capacity to make nuclear weapons presents a threat Israel cannot tolerate for long, particularly in the wake of the Hamas’s Iran-backed massacre of Israelis on October 7, 2023.
A nuclear-armed Tehran would blackmail the West and Jerusalem into standing aside as the regime escalates its support for its terrorist proxies — including Hamas, Hezbollah, and Yemen’s Houthi rebels — throughout the region, potentially threatening Israel’s very existence.
In the end, absent other meaningful options and bolstered by opportunity, a war-weary Israel may need to make the toughest choice of all.
It may have to lead the way to eliminating Tehran’s nuclear threat — and accepting a level of uncertainty about the success of this mission.
Andrea Stricker is a research fellow and deputy director of the Nonproliferation and Biodefense Program at the Foundation for Defense of Democracies (FDD). Follow her on X @StrickerNonpro.
