Hungary has made "huge progress" in emergency works to raise the Danube’s critically low water level at the Paks nuclear power plant with the projected sinking of two barges, Prime Minister Peter Magyar said on August 18, according to state news agency MTI. The next two days will be critical as the river is forecast to fall by another 8-9 centimetres, he warned.

The water levels at Paks were just 8cm short of the critical threshold under which the shutdown of the power plant would be inevitable. The priority over the next 48-60 hours, Magyar stressed in a live Facebook video, is to maintain nuclear safety and keep the two turbines currently generating electricity in operation.

The government’s intervention aims to secure cooling water supplies after an exceptionally severe drought and heatwave pushed the Danube to historic lows. The plant, which has a nominal capacity of about 2,000 MW, was operating at 25% capacity in recent days.

The full shutdown would cost the state at least HUF50bn (€130mn) a month, according to the prime minister; the emergency water-control works are expected to cost about HUF6bn.

Two 80-metre barges are being used as a temporary measure to raise the local water level. The barges were lowered by one metre on August 16 and by another half metre the following day. The barges are the first part of the emergency operation.

The government is also working to build a bottom sill in the area near the nuclear power plant that could provide a long-term fix if water levels fall to extremely low levels. The structure is expected to raise water levels near the cooling channels at Paks.

Construction began over the weekend and is expected to take around 30 days. Officials estimate that about 145,000 cm rock will be needed, with the structure capable of raising water levels at Paks by up to one metre.

The loss of Paks has put huge pressure on an electricity system already facing high summer demand. A recent analysis cited evening Hungarian electricity demand at around 6,400-6,700 MW, with imports accounting for roughly 3,600-4,000 MW. Wholesale prices have also risen sharply during periods of tight supply, with some hourly prices reaching €500-700/MWh.

The Danube’s exceptionally low levels have affected nuclear generation elsewhere in the region. Romania was forced to shut down its last operating reactor at the Cernavodă nuclear plant earlier this month due to insufficient cooling water. The episode has highlighted the vulnerability of river-cooled nuclear facilities to increasingly severe drought and heat extremes.

For Hungary, the situation also raises concerns about the long-term resilience of its nuclear expansion plans. Budapest commissioned Russia’s Rosatom to build two VVER-1200 reactors with a combined capacity of 2,400 MW at the site of the existing plant. The project has faced years of delays, with first concrete finally poured earlier this year.

The current low-water crisis highlights a potential vulnerability for the new reactors, as extreme droughts and heatwaves could become more frequent in the future and, like the existing plant, Paks II, according to current plans, will rely on the Danube for cooling.