Construction on Paks II, Hungary’s 2,400 MW nuclear project, is continuing as the government reviews parts of the project’s contractual and financial structure. The reassessment adds uncertainty to one of Central Europe’s largest energy investments. Work is progressing alongside manufacturing and supply-chain activities.
Reactor-building and nuclear island construction milestones
Progress is most advanced at Unit 5, where preparations for the reactor-building foundation are more than 80 per cent complete. The stage follows the pouring of more than 18,000 cubic metres of concrete. Remaining foundation works are expected to be finished before winter.
Excavation of the nuclear island for Unit 6 is also under way. Preparations for first concrete are planned before the end of 2026. These timelines run in parallel with ongoing work on earlier site structures.
Equipment production and international supply chain
Manufacturing has advanced alongside construction activities. Rosatom has started producing equipment for both VVER-1200 reactors. A 730-tonne core catcher for the first unit was delivered to the Paks site in 2024.
The project’s supply chain includes companies from France, the US, Germany, Austria, Switzerland, the Netherlands, the Czech Republic, Slovakia and Turkey. Alstom began manufacturing turbines for the project at its Belfort facility in April 2025. Equipment production and deliveries are therefore tied to a multi-country procurement base.
Financing structure and potential contract changes
The financing architecture remains a sensitive element of the project. Paks II is supported by a Russian state loan of up to €10bn. Changes to existing contracts or replacement of the principal contractor could require renegotiation of that financing.
If renegotiation becomes necessary, it could delay completion. This risk is linked to how contractual adjustments would interact with the loan structure. Budapest’s review therefore affects both near-term execution and longer-term delivery timing.
Cooling-water resilience amid low Danube levels
Danube water levels have been exceptionally low, prompting questions about cooling-water availability. The issue relates to whether additional measures are needed to strengthen the plant’s ability to operate during drought conditions. Further actions would be assessed alongside other construction-stage priorities.
The source also points to more substantial design changes, including closed-loop cooling. Such changes would add cost and could affect the schedule. Budapest is balancing these longer-term concerns with the high cost of altering a project already deep into construction.
