Iran's Arak heavy water reactor, hit by an Israeli airstrike, was part of Tehran's nuclear deal

San Francisco Chronicle​

5 hours ago

DUBAI, United Arab Emirates (AP) — Much of the focus on Iran's nuclear program has been on Tehran's enrichment of uranium, but experts also keep a close watch on the Islamic Republic's Arak heavy water reactor.
That's because the facility, some 250 kilometers (155 miles) southwest of Tehran, could produce plutonium, which can be used to make an atomic bomb.
Israel pointed to just that concern when it launched airstrikes Thursday on the reactor, following its attacks on other Iranian nuclear sites, including the Nantanz enrichment facility, centrifuge workshops near Tehran, and laboratories in Isfahan. Iran acknowledged the strikes, saying at least two projectiles slammed into the compound, without giving any specifics about damage.
Never online, the reactor had no uranium fuel and saw no nuclear release from the strike. However, the International Atomic Energy Agency, the United Nations' nuclear watchdog, has warned repeatedly that such sites — whether in Iran or Ukraine — should not be military targets.
Arak grew out of Iran's onetime military nuclear program
After Iran's devastating 1980s war with Iraq, it began a secret military program to seek a nuclear weapon and approached four nations to purchase a heavy water-moderated reactor. After getting turned down, Iran decided to build its own.
Heavy water is water in which hydrogen is replaced by deuterium and is used as a coolant for heavy water reactors.
The reactors can be used for scientific purposes, but plutonium is a byproduct of the process. Before the centrifuge technology that enriches uranium to levels high enough for use in weapons became widespread, many states used heavy water reactors to pursue plutonium-fueled bombs.
India and Pakistan, both nuclear-armed states, have heavy water reactors, as does Israel, which has never acknowledged having atomic weapons but is widely believed to have them.
Though Iran ultimately embraced uranium-enriching centrifuges as the main driver of its program, it built the reactor, which never went online.
Iran has long maintained its program is for peaceful purposes. However, it also had been enriching uranium up to 60%, a short, technical step away from weapons-grade levels of 90%. Iran was the only non-nuclear-weapon state to enrich at that level.
Arak was part of Iran's nuclear deal with world powers
Iran agreed under its 2015 nuclear deal with world powers to redesign the facility to alleviate proliferation concerns. That included pouring concrete into part of it, though the overall work never was completed.
The Arak reactor became a point of contention after U.S. President Donald Trump withdrew from the nuclear deal in 2018. Ali Akbar Salehi, a high-ranking nuclear official in Iran, claimed on Iranian state television in 2019 that Tehran bought extra parts to replace the portion of the reactor into which officials poured concrete.
Due to restrictions Iran has imposed on inspectors, the IAEA has said it lost 'continuity of knowledge' about Iran's heavy water production — meaning it could not absolutely verify Tehran's production and stockpile.
Israeli strike likely heavily damaged the inert reactor
On Thursday morning, Israel carried out an airstrike on the reactor. Black-and-white footage of the strike it released showed a bomb dropping on its dome and sending up a massive plume of fire and smoke. The U.N. nuclear watchdog noted that since it was not in operation and contained no nuclear material, there was no danger to the public after the strike from any 'radiological effects.' The IAEA said it had no information on whether the facility nearby where heavy water is produced had been hit.
'The strike targeted the component intended for plutonium production, in order to prevent the reactor from being restored and used for nuclear weapons development,' the Israelis said.
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