Ukraine’s nuclear power sector has become one of the most important parts of the country’s wartime economy. Before the full-scale Russian invasion, nuclear generation already supplied more than half of national electricity. That role has become even more important as thermal power plants, substations and transmission lines have been damaged by repeated attacks. Nuclear plants cannot solve every shortage, but the reactors still controlled by Ukraine provide large volumes of stable electricity that are difficult to replace.
The country’s nuclear system is also divided in a way that has no normal commercial comparison. Ukraine has 15 power reactors across four nuclear plants, but the six units at the Zaporizhzhia Nuclear Power Plant have been under Russian occupation since March 2022 and are not producing electricity. The nine reactors at Rivne, Khmelnytskyi and South Ukraine therefore carry the active nuclear system, while Zaporizhzhia remains both a lost generating asset and an international nuclear safety concern.
Three Nuclear Plants Carry the Wartime Power System
Rivne, Khmelnytskyi and South Ukraine are the foundation of nuclear generation in territory controlled by the Ukrainian government. Together, they contain nine reactors with roughly 7.8 GW of generating capacity. Rivne operates two VVER-440 units and two larger VVER-1000 units. Khmelnytskyi has two operating VVER-1000 reactors, while South Ukraine has three.
These plants have continued to generate electricity through air raids, missile attacks and repeated disruptions to the high-voltage network. Their output supports households, public services, transport systems and industry, but their performance depends on more than the condition of the reactors. Nuclear plants need stable connections to the national grid so they can send electricity out and receive power for essential systems when a reactor is shut down.
This makes transmission infrastructure a central part of Ukraine’s nuclear story. Damage to substations and power lines has forced reactor units to reduce output, disconnect from the grid or shut down automatically. Even when a nuclear plant itself is not struck, an attack on nearby electrical infrastructure can interrupt operations. The high-voltage network has deteriorated further during the war, increasing the risks faced by operating reactors.
Maintenance also remains essential. Ukraine cannot run every reactor at full output continuously because units still require refuelling, inspections and planned repairs. The operator, Energoatom, must balance seasonal electricity demand with outage schedules while also managing wartime security and supply-chain pressures.
Zaporizhzhia Is a Lost Power Source and an Ongoing Safety Risk
Zaporizhzhia is the largest nuclear power plant in Europe, with six VVER-1000 reactors and a total installed capacity of about 6 GW. Before the invasion, it was one of the most important generating sites in Ukraine. Since Russian forces occupied the plant in March 2022, all six units have been shut down and the site has stopped supplying electricity to the Ukrainian grid.
A shut reactor still requires electricity, cooling, trained staff and functioning safety systems. Zaporizhzhia had ten external power connections before the war, but repeated damage has reduced the plant to dependence on a much smaller number of available lines. By June 2026, the site was again relying on a single off-site connection while work continued to restore another line. Loss of external power forces the plant to use emergency diesel generators for essential cooling and safety functions.
The destruction of the Kakhovka dam in 2023 also changed the plant’s long-term water situation. The reactors are in cold shutdown, which reduces cooling requirements, but the plant still needs a reliable solution for cooling reactor systems and spent fuel. Military activity, mines, restricted access and uncertainty over staffing continue to complicate maintenance and inspections.
The future of Zaporizhzhia cannot be separated from the wider war. Restarting the reactors would require secure control of the site, dependable electricity and water supplies, qualified personnel, regulatory oversight and a stable operating environment. Until those conditions exist, the plant is more important as a nuclear safety challenge than as a source of electricity.
Chornobyl Remains Part of the Nuclear Security Burden
Ukraine’s nuclear responsibilities extend beyond operating power plants. Chornobyl’s reactors are permanently shut down, but the site still contains spent fuel, radioactive waste and the damaged Unit 4 reactor covered by the New Safe Confinement structure.
A drone strike in 2025 damaged the confinement structure. A later safety assessment found that the damage affected ventilation and leak-tightness, creating a need for stabilization and repair. Chornobyl does not produce electricity, but it continues to require skilled workers, reliable power, monitoring systems and international support. The site shows why Ukraine’s nuclear sector includes major decommissioning and waste-management duties in addition to power generation.
Ukraine Has Broken Its Dependence on Russian Nuclear Fuel
One of the most significant structural changes in Ukrainian nuclear energy is the move away from Russian fuel. Ukraine had worked with Westinghouse for years before 2022, but the invasion accelerated the transition. Westinghouse now supplies fuel for Ukraine’s operating VVER reactors, including the smaller VVER-440 units at Rivne.
The first Westinghouse fuel was loaded into a Rivne VVER-440 reactor in 2023. Energoatom has also started developing domestic production of fuel-assembly components under Westinghouse licensing. Serial production of components for VVER-1000 fuel assemblies has been planned from 2026, although the pace will depend on certification, industrial capacity and wartime conditions.
Ukraine has also reduced its dependence on Russia for spent-fuel services. A centralized dry storage facility developed with Holtec began full operation in 2023 for fuel from Rivne, Khmelnytskyi and South Ukraine. The facility allows Ukraine to store spent fuel domestically rather than sending it to Russia and paying for external storage. By May 2026, the fiftieth storage container had been installed.
These changes do not remove every foreign dependency. Ukraine still relies on international partners for enrichment, fuel technology, equipment and finance. However, the supply chain is now aligned much more closely with Western nuclear companies and institutions.
Khmelnytskyi Sits at the Centre of Expansion Plans
Ukraine does not view nuclear power only as a system to preserve during the war. Energoatom has presented plans to increase total nuclear capacity from 13.8 GW to more than 20 GW. The main proposals involve completing Khmelnytskyi Units 3 and 4, building two Westinghouse AP1000 reactors at the same site and developing small modular reactors in cooperation with international partners.
Khmelnytskyi is the logical centre for expansion because it already has operating reactors, grid connections, land, staff and partially completed construction. New units could replace lost generating capacity, support post-war reconstruction and strengthen electricity exports to Europe.
The plans remain ambitious rather than guaranteed. Large nuclear projects require long-term financing, secure construction sites, regulatory approvals, imported equipment and confidence that the transmission network can absorb the output. Questions also remain over the design and equipment proposed for the unfinished units.
Nuclear Power Will Shape Ukraine’s Reconstruction
Ukraine’s nuclear sector is likely to remain the backbone of the national electricity system for many years. The immediate priority is keeping the nine reactors under Ukrainian control safe and available while protecting the substations and transmission lines that allow them to operate. The future of Zaporizhzhia will depend on the outcome of the war and the ability to restore accepted regulatory and safety conditions.
Longer term, Ukraine has a clear strategic direction: maintain its existing fleet, remove Russian fuel-cycle dependence, expand domestic nuclear capabilities and add new capacity at Khmelnytskyi. Whether those plans become operating reactors will depend on security, financing and reconstruction of the wider power grid. Nuclear energy is therefore both a present source of resilience and a central part of Ukraine’s post-war energy strategy.
