Israel attacked Iran’s Arak heavy water reactor on Thursday morning, as Iranian missiles evaded Israeli air defences to hit a hospital in the country’s south and sites around Tel Aviv.

Iran had evacuated the Arak facility before the attack and there was “no radiation danger”, state TV said in a report on the bombing. Few hours ago IDF had issued evacuation warning for residents in Iran’s Arak and Khandab.

The Arak facility, officially known as the Khondab Heavy Water Research Reactor (IR-40), is a critical component of Iran’s nuclear program due to its potential to produce plutonium, a material that can be used in nuclear weapons, alongside its stated civilian purposes. Located approximately 250 km southwest of Tehran, the facility includes a 40-megawatt heavy water reactor and an associated heavy water production plant.

The Arak reactor, in its original design, was capable of producing 8–10 kg of weapons-grade plutonium annually in its spent fuel, sufficient for 1–2 nuclear weapons per year. Plutonium offers an alternative pathway to nuclear weapons compared to highly enriched uranium, which is produced at other Iranian facilities like Natanz. This dual-path capability makes Arak a focal point of international concern, as it diversifies Iran’s potential routes to nuclear armament.

Unlike light water reactors, heavy water reactors like Arak can operate with natural uranium, eliminating the need for uranium enrichment to produce fuel. However, the spent fuel from such reactors contains plutonium, which can be extracted through reprocessing for use in nuclear weapons.