Iran Backs $25 Billion Sirik Nuclear Plant as IAEA Access Narrows

Russian state nuclear corporation Rosatom confirmed that 135 engineering and technical specialists returned to the Bushehr nuclear plant in Iran by October 11. This workforce represents the core group that evacuated after the US-Iran war began in February. The return signals a resumption of active operations at the site, which remains the central point of Russian-Iranian nuclear cooperation.

The staffing at Bushehr coincides with the progression of two additional reactor units at the site. Rosatom stated that construction on the second unit has surpassed 60 percent completion. The corporation targets the start of operations for that unit in 2029. A third unit is also under construction. These projects extend the footprint of the facility, which began full commercial electricity generation in 2013 despite a contract signed in 1995.

Beyond Bushehr, the two nations signed an agreement in September 2025 to build the Sirik nuclear power plant. The project is located in Hormozgan Province, close to the Strait of Hormuz. Iranian state news agency IRNA reported the deal is valued at $25 billion. The new facility will have a combined capacity of approximately 5 gigawatts. This capacity exceeds the finished Bushehr complex, which will have a capacity of under 3 gigawatts.

The expansion of nuclear infrastructure occurs while the International Atomic Energy Agency faces difficulties in monitoring Iran’s sites. In a report published on June 4, the IAEA detailed its inspection at Bushehr from June 1 to 3. The agency stated it could not conduct inspections at four uranium enrichment facilities during that period. The IAEA also reported it could not verify the status of nuclear material or confirm the suspension of enrichment and reprocessing activities required by UN Security Council resolutions.

The legal framework for this cooperation relies on the Comprehensive Strategic Partnership Treaty, which entered into force in October 2025. A specific intergovernmental Cooperation Plan for 2024-2026, approved in September 2024, provides the practical roadmap. Analysts note that the balance of this relationship favors Russia. Nikita Smagin of the Carnegie Endowment for International Peace wrote in November 2025 that Russia remains one of the few available sources of investment for Iran. Dmitry Kovchegin and Arkady Mil-Man of Israel’s Institute for National Security Studies described Moscow’s approach as a calculated balancing strategy in a June analysis.

The partnership deepens amid Western sanctions on both nations. Russia faces measures targeting its energy, finance, and defense sectors following its 2022 invasion of Ukraine. Iran has faced restrictions for decades over its nuclear program and military activities. The US-based Center for Naval Analyses found that military and technical cooperation between the two countries has expanded since 2022. The Arms Control Association noted in June 2025 that Iran’s enrichment of uranium to 60 percent puts the country in a better position to produce weapons-grade material.