Hungary’s controversial Paks II nuclear power plant could be delayed by at least two years, with an internal Rosatom schedule reportedly pushing the completion of the final reactor to the end of 2034. The EUR 12.5 billion project may therefore not become fully operational until 2035.

The construction of Hungary’s Paks II nuclear power plant could take significantly longer than previously announced, according to confidential documents obtained by POLITICO.

An internal construction schedule from Russia’s state-owned Rosatom, which is responsible for building the Russian-designed plant, reportedly puts the date for the provisional acceptance of the second reactor at 30 December 2034.

Provisional acceptance would mark the point at which Rosatom hands the completed facility over to the Hungarian state-owned operator for final checks. That means the approximately EUR 12.5 billion project is unlikely to be fully operational before 2035.

The reported timetable would represent a significant setback compared with previous government statements. Earlier this year, when Viktor Orbán was still prime minister, the Hungarian government said the two new reactors could be completed between 2031 and 2032.

Another delay for Hungary’s biggest nuclear project

The reported schedule is the latest indication that Paks II has fallen significantly behind its original plans. According to the spreadsheet seen by POLITICO, the first concrete pour for Unit 5 was originally scheduled for March 2025. The work ultimately began in February 2026 — almost a year later.

The document indicates that the first concrete for Unit 6 is scheduled for September this year. The final regulatory milestones, including obtaining the operating licence and reaching provisional acceptance for Unit 6, are both listed for 30 December 2034.

Metadata suggests that the spreadsheet was originally created in 2015 and subsequently updated several times. However, it is unclear when it was last amended, meaning the timetable cannot independently be confirmed as Rosatom’s current official schedule. Rosatom itself has disputed the significance of the document without directly challenging its contents.

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Rosatom: Project remains on schedule

Asked about the spreadsheet, Rosatom said it had not seen the document and therefore would not comment on it. The Russian nuclear giant nevertheless said that, under the current schedule agreed with the Hungarian side, the reactors would be completed within the previously established timeframe. It did not provide a specific completion date.

Rosatom said foundation work on Unit 5 was around 80 per cent complete and would be finished by the end of the year, after which preparations would begin for the first concrete pour for Unit 6. Paks II Ltd., the Hungarian state-owned company overseeing the project, also declined to provide detailed information while the new government’s review is under way.

“Given the complexity of the investment, this is necessarily a time-consuming process,” a company spokesperson said, adding that more detailed information would be available once the review was completed.

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New government reviewing the Russian-backed project

Paks II has become an especially sensitive issue since Péter Magyar replaced Viktor Orbán as prime minister in April 2026. Magyar has been openly critical of Russia and his government has launched a review of the nuclear expansion project.

The latest revelations therefore come at a politically important moment. The new administration must decide how to proceed with a project that has already absorbed substantial public funds, while also weighing Hungary’s long-term energy needs. The two planned reactors are intended to play a crucial role in replacing Hungary’s existing nuclear capacity.

Paks II is crucial to Hungary’s energy future

The existing Paks nuclear power plant currently generates around 2,000 megawatts and supplies a substantial share of Hungary’s electricity. Its four Soviet-era reactors are expected to be retired between 2032 and 2037. The two new Russian-designed reactors at Paks II would provide a combined 2,400 megawatts, more than replacing the capacity of the existing plant.

That makes the timing of Paks II particularly important. If the new reactors are not operational before the existing units begin shutting down, Hungary could face a potentially significant gap in domestic nuclear generating capacity. The project has also been controversial from the beginning because of its close links to Russia.

Paks II was agreed in 2014 by then-prime minister Viktor Orbán and Russian President Vladimir Putin, with Rosatom selected to construct the two new VVER-1200 reactors. More than a decade later, however, construction of the reactors themselves is still in its relatively early stages.

Safety concerns add to the controversy

The latest report also follows POLITICO’s investigation into alleged safety concerns and potential negligence at another Rosatom nuclear project in Egypt. The Egyptian facility uses the same reactor technology planned for Paks II. Rosatom has rejected the allegations and defended its safety standards and working practices.

The documents obtained by POLITICO reportedly came from an intelligence official who requested anonymity. The same source had previously provided documents used in the reporting about the Egyptian project. The Hungarian government declined to comment on the latest report.

Could Hungary eventually abandon Paks II?

The potential delay is likely to intensify the debate over whether Hungary should continue with the project at all. Former Green Party lawmaker Benedek Jávor, a long-time critic of Paks II, argued that the government should recognise the financial risks associated with the project and consider abandoning it.

Hungary has already spent around HUF 1,000 billion on Paks II, according to Jávor.

For the new government, the choice is therefore becoming increasingly difficult. Cancelling the project could mean writing off substantial investment and creating a major hole in Hungary’s future energy plans. Continuing with it could mean committing to a hugely expensive Russian-backed project that is already facing delays and remains politically controversial.