Paks II schedule risk extends into 2035
Hungary’s Paks II nuclear expansion could see completion pushed to 2035, according to an internal construction timetable cited in a report. The same source indicates the project could be delayed until 2035, narrowing the time gap between commissioning of the new reactors and retirement of Hungary’s existing nuclear fleet.
The report links the potential shift to the timing of provisional acceptance for unit 6. It places provisional acceptance on Dec. 30, 2034, with commercial operation expected to follow that milestone. If commercial operation begins after that date, completion could move into 2035.
Existing Paks units slated for shutdown between 2032 and 2037
The existing Paks plant comprises four Soviet-era units with combined capacity of about 2 GW. Shutdowns are expected to begin between 2032 and 2037. This creates a schedule overlap risk if the new build does not reach full operational status before retirements start.
The report notes that earlier Hungarian government indications pointed to reactor completion in 2031-2032. The later timing implied by the internal timetable would therefore be behind those earlier projections.
Reactor design and construction milestones for units 5 and 6
Paks II is designed to replace and expand the existing capacity using two VVER-1200 reactors totalling 2.4 GW. The project’s schedule has already moved past some earlier milestones cited in the report. First concrete for unit 5 was originally expected in March 2025 but was poured in February 2026.
For unit 6, first concrete is scheduled for September 2026. Rosatom has said construction is proceeding according to the timetable agreed with Hungary, but it has not publicly provided a firm commissioning date. Foundation work on unit 5 was reported at about 80% complete and expected to finish by year-end.
Potential gap between retirements and full Paks II operation
The report says further delays would increase the risk of a period in which Hungary’s existing reactors begin retiring before Paks II is fully operational. It also points to longer-term questions over replacement capacity, imports, and security of supply.
No firm commissioning date has been publicly stated by Rosatom in connection with the agreed timetable, even as construction progress is described as aligned with that plan. The report’s cited acceptance milestone for unit 6 remains Dec. 30, 2034, with commercial operation expected afterward.
