Iran is drafting an urgent bill to withdraw from the Nuclear Non-Proliferation Treaty.

According to the Associated Press, construction work at the Shimon Peres Nuclear Research Center in the Negev, near the city of Dimona, raises questions about Israel’s status, widely believed to be the only nuclear-armed state in the Middle East.

This construction could also provoke international criticism, especially since it follows Israeli and US strikes on nuclear sites across Iran in June, due to concerns that the Islamic Republic might use its enrichment facilities to pursue nuclear weapons. Among the attacked sites was Iran’s heavy water reactor in Arak.

Experts Provide Their Analysis (According to AP):

Seven experts who examined the images believe the construction is linked to Israel’s long-suspected nuclear weapons program, given its proximity to the Dimona reactor, where there is no civilian power plant. However, they differ on the nature of the new construction.

Three of them said the location, size, and the fact that the structure appears multi-story make the most likely explanation the building of a new heavy water reactor. Such reactors can produce plutonium and other key materials for nuclear weapons.

The other four acknowledged the possibility of a heavy water reactor but also suggested the work could be related to a new nuclear weapons assembly facility. They refrained from certainty as the construction is still in early stages.

Jeffrey Lewis, an expert at the James Martin Center for Nonproliferation Studies at the Middlebury Institute of International Studies, based his assessment on the images and Dimona’s history: “It is likely a reactor, and this assessment is circumstantial but that’s the nature of these things. It’s very hard to imagine it being anything else.”

The Israeli government has neither confirmed nor denied possessing nuclear weapons and did not respond to requests for comment. The White House, Israel’s strongest ally, also did not respond to requests for comment.

The Associated Press first reported excavation work at the facility, about 90 kilometers (55 miles) south of Jerusalem, in 2021. At that time, satellite images showed workers digging a pit approximately 150 meters (165 yards) long and 60 meters (65 yards) wide near the site’s original heavy water reactor.

Images taken on July 5 by Planet Labs for the BBC show intensive construction at the excavation site. Thick concrete retaining walls appear to have been installed at the site, which seems to have multiple underground floors, with massive cranes above.

Currently, there is no containment dome or other features typically associated with a heavy water reactor visible at the site, but these could be added later or the reactor could be designed without them. The current Dimona reactor, which entered service in the 1960s, has operated much longer than most reactors from the same era, suggesting it will need replacement or upgrading soon.

Lewis explained: “It is tall, which can be expected because the reactor core will be very high. Based on the location, size, and general absence of construction there, it is more likely a reactor than anything else.”

Edwin Lyman, a nuclear expert at the Union of Concerned Scientists based in Cambridge, Massachusetts, said the new construction could be a box-shaped reactor without a visible containment dome, although he admitted the lack of transparency makes it difficult to be sure.

Lyman said Israel “does not allow any international inspections or verification of what it does, forcing the public to speculate.”

While details about Dimona remain tightly guarded secrets in Israel, a whistleblower in the 1980s revealed details and photos of the facility that led experts to conclude Israel produced dozens of nuclear warheads.

Daryl G. Kimball, executive director of the Arms Control Association based in Washington, said: “If it is a heavy water reactor, they are seeking to maintain the ability to produce spent fuel that can then be processed to separate plutonium for more nuclear weapons,” adding, “Or they are building a facility to maintain their arsenal or build additional warheads.”

Israel’s program is believed to rely on the byproducts of the heavy water reactor. Like India and Pakistan, Israel uses heavy water reactors to make its nuclear weapons. Reactors can be used for scientific purposes, but plutonium—which causes the nuclear chain reaction required in an atomic bomb—is a byproduct of the process. Tritium is another byproduct and can be used to increase the explosive power of warheads.

Due to the secrecy of Israel’s program, it remains difficult to estimate the number of nuclear weapons it possesses. In 2022, the Bulletin of the Atomic Scientists estimated the number at about 90 warheads. Obtaining more tritium to replace decaying materials may be the reason behind the construction at Dimona, with Lyman noting it decays by 5% annually, adding: “If they are building a new production reactor, it does not necessarily mean they are looking to increase their plutonium but to manufacture tritium.”

Israel is believed to have started building the nuclear site in the desert in the late 1950s after facing several wars with its Arab neighbors following its establishment in 1948 after the Holocaust. Its policy of nuclear ambiguity is believed to have helped deter its enemies.

Israel is among nine countries confirmed or believed to possess nuclear weapons and one of only four countries never to have joined the Nuclear Non-Proliferation Treaty, a historic international agreement aimed at halting the spread of nuclear weapons. This means the International Atomic Energy Agency, the UN nuclear watchdog, has no right to inspect the Dimona site.

When asked about the construction, the Vienna-based International Atomic Energy Agency reiterated that Israel “is not obligated to provide information about other nuclear facilities in the country” outside its research reactor in Soreq.