Construction on Paks II, Hungary’s 2,400 MW nuclear project, is continuing as the government reviews elements of the project’s contractual and financial structure. The review adds uncertainty around one of Central Europe’s largest energy investments. Work progress is reported across both civil works and component manufacturing.
Reactor-building works for Units 5 and 6
Preparations for the reactor-building foundation at Unit 5 are more than 80% complete. The stage follows the pouring of more than 18,000 cubic metres of concrete. Remaining foundation works are expected to be completed before winter.
Excavation of the nuclear island for Unit 6 is also progressing. Preparations for first concrete are planned before the end of 2026. These timelines are part of the parallel schedule for different parts of the site.
Manufacturing progress and international supply chain
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. Manufacturing activity is described as moving ahead alongside construction.
The supply chain includes companies from France, the US, Germany, Austria, Switzerland, the Netherlands, the Czech Republic, Slovakia and Turkey. Alstom began manufacturing turbines at its Belfort facility in April 2025.
Financing structure and potential renegotiation risks
The financing architecture remains a sensitive issue for the project. Paks II is supported by a Russian state loan of up to €10bn. The government’s ongoing review focuses on parts of the contractual and financial structure.
If major changes are made to existing contracts or if the principal contractor is replaced, renegotiation of that financing could be required. Such renegotiation could potentially delay completion.
Cooling-water resilience amid low Danube levels
Environmental resilience has become an additional consideration for operations planning. Exceptionally low Danube levels have raised questions about cooling-water availability. The issue includes whether further measures are needed to strengthen operation during drought conditions.
More substantial design changes, including closed-loop cooling, would add cost and could affect the schedule. Budapest is weighing those longer-term concerns against the high cost of changing a project already deep into construction.
