Russia and Iran agree to build $25 billion nuclear plant

Russia and Iran have deepened their nuclear partnership in recent years, a move driven by Western sanctions and mutual isolation.

In September 2025, the two nations signed an agreement to construct a new nuclear power plant called Sirik. Located in Iran’s southern Hormozgan Province near the Strait of Hormuz, the project is valued at $25 billion. Iran’s state news agency IRNA reported that the plant’s units will have a combined capacity of approximately 5 gigawatts. This is larger than the finished Bushehr complex, which has a capacity of under 3 gigawatts.

The Sirik deal builds on the long-standing relationship between Russia’s state nuclear corporation Rosatom and Iran. Rosatom has operated the Bushehr plant on Iran’s southern coast since 2013, after completing the first reactor unit under a contract signed in 1995. Construction is currently underway on two additional reactor units at Bushehr. Rosatom stated that the second unit is more than 60 percent complete and targets operations in 2029, while work has also begun on a third unit.

Rosatom has maintained its presence at Bushehr despite regional military conflicts. After the start of the US-Iran war in February, the corporation evacuated most of its staff. However, by October 11, Rosatom reported that 135 engineering and technical specialists had returned to the site. The legal framework for this cooperation is the Comprehensive Strategic Partnership Treaty, which entered into force in October 2025, and the intergovernmental Cooperation Plan for 2024-2026.

Analysts suggest the partnership benefits both sides, though the balance may favor Moscow. Nikita Smagin, an analyst at the Carnegie Endowment for International Peace, wrote in November 2025 that the relationship is shifting in Russia’s favor because Iran requires investment. Dmitry Kovchegin and Arkady Mil-Man of Israel’s Institute for National Security Studies described Moscow’s approach as a calculated balancing strategy. They noted that Russia provides limited assistance while seeking to improve relations with the United States.

International oversight of these activities faces obstacles. In a report published on June 4, the International Atomic Energy Agency said it inspected Bushehr from June 1 to 3. The agency stated it could not conduct inspections at other declared nuclear sites during that period. This includes four uranium enrichment facilities. The IAEA also reported it could not verify the status of nuclear material or confirm that Iran had suspended uranium enrichment and reprocessing of spent fuel as required by resolutions.

Nonproliferation specialists have raised concerns about transparency as Russian and Iranian cooperation expands. The US-based Arms Control Association noted in June 2025 that Iran’s accumulation of uranium enriched to 60 percent has no civil justification. While not weapons-grade, this material can be enriched further to the 90 percent level generally associated with nuclear weapons.

The expansion of nuclear ties comes as both countries face extensive sanctions. Russia’s measures target energy, finance, and defense sectors following its 2022 invasion of Ukraine. Iran faces decades of restrictions over its nuclear program and military activities. A 2025 analysis by the Center for Naval Analyses found that Russia and Iran have expanded military contacts and arms transfers since 2022.