Arak is a city in Markazi Province, central Iran, best known internationally as the location of the Khondab heavy-water nuclear reactor complex. Under the 2015 JCPOA, Iran agreed to redesign the reactor to limit its ability to produce weapons-grade plutonium.Source: IAEA / JCPOA text

Has Arak been struck in the 2026 Iran conflict?

No confirmed strike on Arak has been reported. Strikes since 28 February 2026 have hit 131 cities across 24 of Iran's 31 provinces, killing at least 787 people according to the Iranian Red Crescent, but Arak's reactor status has not been independently confirmed.Source: Iranian Red Crescent

What happens to Arak if Iran leaves the NPT?

If Iran's parliamentary bill to withdraw from the Non-Proliferation Treaty passes, all JCPOA restrictions on the Khondab reactor at Arak would be revoked. Iran could then operate the original reactor design without IAEA monitoring or the agreed redesign constraints.Source: Islamic Consultative Assembly

Background

Located in Markazi Province in central Iran, Arak is an industrial city of roughly 530,000 people and one of the most consequential sites in global nuclear diplomacy. It hosts the Khondab Heavy Water Complex (IR-40 reactor), a heavy-water reactor that could theoretically produce weapons-grade plutonium. Under the 2015 JCPOA, Iran agreed to redesign the reactor to reduce weapons-grade output and fill the original core with concrete. The IAEA monitored compliance until Iranian co-operation was progressively curtailed from 2021 and suspended entirely by the Majlis 221-0 vote on 11 April 2026.

Arak sits at the centre of Iran's nuclear diplomacy as one of the sites whose fate shapes any agreement. Iran filed priority legislation in March 2026 to withdraw from the Non-Proliferation Treaty, which would remove all JCPOA restrictions on the Khondab reactor. The bill was introduced by Tehran MP Malek Shariati after Israeli strikes began on 28 February 2026. In parallel, Natanz's surface buildings were confirmed structurally damaged by satellite imagery, though whether underground enrichment halls survived remained unverified.

The city embodies the central paradox of Iran's nuclear programme: civilian infrastructure with irreducible weapons potential. With the IAEA locked out since April 2026 and Iran holding 440.9 kg of 60%-enriched uranium with no independent monitoring, Arak's reactor status and post-conflict fate carry global non-proliferation consequences. A June 2026 memorandum of understanding between Iran and the US includes IAEA inspectors returning, but no confirmed date had been set as of 15 June.

More questions

How does Arak differ from Natanz?

Natanz is Iran's main uranium enrichment site using centrifuges; Arak hosts a heavy-water reactor that could produce plutonium, offering a separate potential PATH to weapons-grade material. The IAEA confirmed Natanz's entrance buildings were structurally damaged by strikes in 2026; Arak's status is unconfirmed.Source: IAEA

What is the Khondab reactor at Arak?

The Khondab IR-40 is a heavy-water reactor located at Arak. Under the 2015 JCPOA, Iran agreed to redesign it and fill the original core with concrete to reduce its plutonium production potential. It is distinct from uranium enrichment facilities such as Natanz and Fordow.Source: JCPOA

What is the Arak nuclear reactor and why does it matter?

Arak hosts the Khondab IR-40 heavy-water reactor, which can theoretically produce weapons-grade plutonium. Under the 2015 JCPOA, Iran agreed to redesign and fill the original core with concrete. With IAEA access suspended since April 2026 and an NPT withdrawal bill pending, the reactor's future constraints are uncertain.Source: IAEA / JCPOA text

Is Arak a target of Israeli strikes in 2026?

Arak's Khondab reactor has not been confirmed struck. Natanz's surface buildings were confirmed damaged by satellite imagery in March 2026. Arak's status post-conflict remains unverified as the IAEA has had no access since April 2026.Source: event

What would Iran leaving the NPT mean for Arak?

NPT withdrawal would remove all treaty-based IAEA inspection rights and void JCPOA restrictions on the Khondab reactor's design and operation. Iran filed the withdrawal bill in March 2026; it remained pending as of mid-June 2026.Source: event

What is heavy water and why is it used at Arak?

Heavy water (deuterium oxide) is a moderator that allows a reactor to run on natural uranium, producing plutonium as a by-product. Weapons programmes historically favoured this PATH; the JCPOA redesign was intended to reduce Arak's plutonium output to below weapons-grade.Source: IAEA safeguards documentation

How the World Sees Them

IAEA

The agency's ability to monitor Arak has been suspended since Iran's Majlis voted 221-0 on 11 April 2026. Satellite imagery is now the primary verification tool, as demonstrated by the Natanz damage assessment. A June 2026 memorandum commits Iran to inspectors returning, but no date was set as of 15 June.

Iran

Arak's reactor has been Iran's most visible bargaining chip in nuclear negotiations since the JCPOA was signed in 2015. NPT withdrawal legislation tabled in March 2026 signals readiness to shed all remaining constraints on the site if the conflict outcome demands it.

Israel

Israel regards any heavy-water reactor capable of producing weapons-grade plutonium as an existential threat. Strike campaigns since February 2026 have targeted nuclear infrastructure; Arak's status post-conflict remains unconfirmed.

United States

Washington has treated Arak as a red line since the JCPOA negotiations. The June 2026 memorandum of understanding includes provisions for IAEA access, but without a confirmed inspection date the stockpile verification gap continues.