Danube's Record Low Levels Force Nuclear Plants in Hungary and Romania to Cut Output

Record-low water levels in the Danube River are disrupting nuclear power generation in Eastern Europe, forcing Hungary to drastically cut output at its Paks plant and Romania to shut down its last operating reactor. The crisis has intensified discussions about how to adapt atomic energy infrastructure to a hotter, drier climate.

Hungary's 2-gigawatt Paks facility, which normally supplies about half of the country's electricity, was reduced to just over 10% capacity earlier this month, narrowly avoiding its first full shutdown in 44 years. It is currently running at only a quarter of its normal output. In Romania, state-owned Nuclearelectrica was forced to idle its final working reactor after efforts to divert cooling water proved insufficient.

Both countries rely on Danube water to cool their reactors, a design that has long been a vulnerability during summer heatwaves. While nuclear power is a carbon-free baseload energy source and a key tool in fighting climate change, the increasing frequency of extreme weather events is exposing its dependence on water availability.

Scientists warn that Central and Eastern Europe is trending drier, not just from reduced rainfall but also from depleted soil moisture and groundwater. Water engineers had already cautioned that flow patterns on the Danube could become more extreme and volatile.

In response, Hungary's government has proposed building a submerged riverbed sill to raise water levels and has considered sinking barges to avert a shutdown as the river is expected to shrink further. The country is also reviewing designs for its planned Paks 2 expansion, which would also rely on the Danube for cooling.

Romania, which operates two 706-megawatt CANDU reactors using heavy-water technology, has approved a project to lift the riverbed of the Bala branch to manage water flow. The project, valued at about $225 million, has been delayed, but officials say studies show it would allow four reactors to operate at full capacity.

Experts suggest hybrid cooling systems, combining river water with cooling towers, as a potential solution. However, retrofitting such towers to existing reactors may not be economical given their remaining lifespan. A fresh evaluation of cooling methods is considered necessary as both nations push forward with nuclear expansion plans while grappling with the realities of a changing climate.