Nuclear energy is not a secondary part of Hungary’s electricity system. It is the system’s central source of domestic generation.
Four reactors at the Paks Nuclear Power Plant produce approximately half of the electricity generated in Hungary. The government plans to preserve this role through two parallel programs: extending the operating lives of the existing units and constructing two much larger reactors under the Paks II project.
This strategy offers Hungary a large supply of low-carbon electricity from a single site. It also creates significant technical, financial and geopolitical exposure. The existing reactors were built using Soviet technology, while Paks II is being delivered through a Hungarian-Russian agreement at a time of strained relations between Russia and the European Union.
Hungary’s nuclear future therefore depends not only on construction. It also depends on the condition of the original reactors, fuel diversification, European legal decisions and the country’s ability to manage six units at Paks during a possible period of overlapping operation.
Paks Is the Foundation of Hungary’s Electricity Supply
The Paks Nuclear Power Plant stands beside the Danube in central Hungary, around 100 kilometers south of Budapest. Its four VVER-440 pressurized water reactors entered commercial operation between 1982 and 1987.
Together, the units have approximately 1.9 GW of generating capacity. They produced 16.017 TWh of electricity in 2024, accounting for approximately half of Hungary’s domestic electricity production.
This concentration gives Paks exceptional national importance. A major outage or early closure would not remove only one source from a diversified market. It would create a large gap in domestic generation and increase dependence on electricity imports or fossil-fuel power plants.
Nuclear generation also supports Hungary’s climate policy. The reactors produce electricity without direct carbon dioxide emissions during operation, complementing the rapid growth of solar power. Solar generation is strongest during daylight hours and changes with weather conditions, while Paks provides continuous output.
The two technologies can support the same low-carbon strategy, but their interaction also requires better grid management. Periods of high nuclear and solar generation may create excess supply, while evening demand must be covered after solar output declines. Hungary is therefore investing in networks, storage, flexible generation and cross-border electricity connections alongside its nuclear program.
Lifetime Extensions Are Intended to Protect the Existing System
The four original reactors were designed for shorter operating lives than Hungary now expects from them. Each unit has already received a 20-year extension, allowing Unit 1 to operate until 2032, Unit 2 until 2034, Unit 3 until 2036 and Unit 4 until 2037.
MVM, the state-owned energy group that controls the plant, is preparing applications for another 20 years of operation. If approved, the reactors could continue producing electricity into the 2050s.
A second extension would require detailed examination of reactor vessels, cooling systems, electrical equipment, concrete structures and other components affected by aging. Some systems can be replaced or modernized. Others, particularly large structural components, require extensive analysis to prove that they can continue operating safely.
The timing is strategically important because Paks II has experienced a much longer development period than originally expected. Extending the existing reactors reduces the risk that Hungary will lose nuclear capacity before the new units enter service.
It could also create a period in which all six reactors operate at the same location. The combined capacity of the existing plant and Paks II would exceed 4 GW. Hungary would need sufficient electricity demand, export connections and grid flexibility to use this output efficiently.
The Danube is another operational consideration. Both the current and future reactors depend on the river for cooling. Water temperature and flow conditions must be managed carefully, particularly during hot and dry periods when electricity demand may also be high.
Paks II Has Moved Into Nuclear Construction
Hungary and Russia signed their agreement for Paks II in 2014. The project calls for two Russian-designed VVER-1200 Generation III+ reactors, each with approximately 1.2 GW of capacity.
Russia agreed to provide a state loan facility of up to €10 billion, while the Hungarian state would finance the remaining project costs. Rosatom serves as the main contractor, supported by Hungarian and international suppliers.
For years, the project remained in licensing, site preparation and ground engineering. That changed on 5 February 2026, when first concrete was poured for Unit 5. Under the classification used by the International Atomic Energy Agency, this marked the formal start of reactor construction. Excavation at the Unit 6 area also advanced in March 2026.
The new units are intended to replace nuclear capacity as the original reactors eventually retire, support growing electricity demand and reduce the country’s exposure to imported power. They will also increase the importance of Paks as Hungary’s main electricity-producing location.
VVER-1200 reactors include modern safety features such as passive systems and a core catcher designed to contain molten material during a severe accident. However, the project’s success will depend on more than reactor design. Hungary must manage construction quality, regulatory supervision, skilled labor, supply chains and the integration of new equipment from several countries.
The project has already faced schedule changes, licensing delays and difficulties involving international contractors. First concrete represents a major milestone, but it is still an early point in the construction process.
Russian Cooperation Creates Both Continuity and Exposure
Hungary presents its nuclear relationship with Russia as a practical continuation of the country’s existing technical system. Hungarian specialists have decades of experience with VVER reactors, and Russian organizations have long supplied fuel, engineering knowledge and plant services.
Paks II deepens that relationship. Its reactor technology, financing structure and main construction contract are connected to Russia, making the project unusual within the current European political environment.
The war in Ukraine, sanctions and restrictions on Russian companies have complicated payments, equipment procurement and participation by Western suppliers. Hungary has repeatedly sought protections for civil nuclear cooperation, arguing that Paks II is necessary for national energy security.
This creates a distinction between two forms of dependence. Nuclear power may reduce Hungary’s need for imported natural gas and electricity, but a Russian-built and Russian-financed project can create long-term reliance on Russian technical support, components and commercial relationships.
Hungary has started to reduce part of this exposure at the existing Paks plant. Framatome signed an agreement to begin supplying VVER fuel from 2027, while Westinghouse plans to deliver alternative VVER-440 fuel from 2028, subject to licensing. Multiple qualified suppliers could improve security and give the operator more flexibility.
Fuel diversification at the existing reactors does not remove the wider Russian role in Paks II, but it shows that Hungary can separate some parts of nuclear cooperation from a single-country supply chain.
European Legal Scrutiny Adds Financial Uncertainty
Paks II also faces an unresolved European state-aid issue.
The European Commission approved Hungarian state support for the project in 2017. Austria challenged that decision, and the Court of Justice of the European Union annulled the approval in September 2025. The Court concluded that the Commission should have examined whether the direct award of the construction contract complied with EU public-procurement rules.
The ruling did not make nuclear construction illegal in Hungary, but it required the Commission to assess the support again. As of 2026, the Commission was conducting a new formal investigation into the compatibility of the measure with European state-aid rules.
This creates a legal and financial risk while construction proceeds. Hungary must show that its financing and contracting structure can satisfy EU law, even though the original project agreement was negotiated directly with Russia.
Cost control will also remain important. Large nuclear projects require substantial capital before producing electricity, and delays increase financing expenses. The economic case for Paks II will depend on final construction costs, operating performance and the value of its electricity over many decades.
Waste Management Must Expand With the Nuclear Program
Spent fuel from the existing reactors is stored at an interim facility near Paks after an initial cooling period. Hungary also operates a repository at Bátaapáti for low- and intermediate-level radioactive waste.
High-level waste and spent fuel require a longer-term solution. Hungary has studied the Boda Claystone Formation in the Mecsek region as a possible location for a deep geological repository, but development remains a long-term program.
Paks II will increase the total quantity of radioactive material that Hungary must manage. Lifetime extensions for the original units would also produce additional spent fuel and operating waste.
Waste planning therefore cannot be separated from generation policy. Storage capacity, repository research, transport systems and financing arrangements must develop alongside the reactors themselves.
Hungary Is Choosing Nuclear Continuity Rather Than Transition
Hungary’s nuclear strategy is designed to avoid a break between the existing Paks plant and its replacement. The country is extending the old reactors while building new ones, creating several possible layers of nuclear generation at the same site.
The immediate challenge is to keep the original units safe and reliable through their current licensing periods. The next challenge is to complete Paks II under changing legal, financial and geopolitical conditions.
If both programs succeed, nuclear power could remain Hungary’s largest source of domestic electricity well into the second half of the century. If either suffers major delays, the country may require more electricity imports, gas-fired generation or faster investment in alternative capacity.
Hungary has made a clear strategic choice. The future of its power system will not involve replacing nuclear energy, but preserving and expanding it while attempting to control the dependencies that accompany the Paks program.