The Danube has begun falling again at Paks, increasing the threat of further restrictions or even a complete shutdown at the Paks nuclear power plant, Prime Minister Péter Magyar said on Thursday. The government has already begun emergency river-engineering works, while two 80-metre barges are being prepared for possible deployment if the water level drops faster than expected.
According to MTI, the water gauge at Paks stood at around minus 119-120 centimetres on Thursday afternoon. Magyar said even a few centimetres can now make a significant difference to the operation of Hungary’s only nuclear power station.
For foreign readers, the negative figures refer to the local water gauge datum and do not mean that the river itself has a negative depth.
Paks nuclear power plant approaching critical water levels
Experts expect the gauge to fall to around minus 121 centimetres on Friday morning and potentially reach minus 132 centimetres by Sunday or Monday, Magyar said.
That is a crucial threshold. If the river falls to minus 132 centimetres, one of the two turbines currently operating would again have to be shut down.
The medium-term outlook is even more concerning. According to the prime minister, the level could reach minus 136-137 centimetres within six or seven days. At minus 140 centimetres, the entire Paks nuclear power plant would have to be taken offline.
At present, only two of the plant’s eight turbines are operating, producing almost 500 megawatts of electricity.
Magyar stressed that Danube levels can be forecast with reasonable confidence only a few days in advance, rejecting claims that the exact severity of the current situation could have been predicted months ago.
The crisis is not unique to Hungary. Romania began shutting down the last operating reactor at its Cernavodă nuclear power plant on Thursday because of historically low Danube levels, after its other reactor had already been taken offline in late July.
Emergency bed sill already under construction
The government’s main intervention is the construction of a riverbed sill between Paks and Dunaszentbenedek, close to the nuclear plant’s cold-water intake channel.
The structure is intended to raise the upstream water level sufficiently to maintain the cooling-water supply required by the plant.
Around 145,000 cubic metres of rock are planned to be placed in the Danube. The first 35,000 cubic metres will form a transverse rock ridge designed to produce a meaningful rise in the water level. Another 110,000 cubic metres will later reinforce the riverbed and protect the structure against erosion caused by the Danube’s current.
The project is technically challenging. Gacsályi József, deputy technical director-general of Hungary’s National Directorate General for Water Management, said around 800 cubic metres of water per second currently pass through the river section where the structure is being built.
The sill will be constructed across a section of roughly 300 metres between the plant’s cold- and warm-water channels.
Work is taking place on both banks. Hungarian soldiers are working primarily on the left bank, which can be accessed on dry ground, while contractors and water-management specialists are operating on the deeper right-hand side.
Heavy machinery is already arriving, access roads and storage areas are being prepared, and the first quantities of rock have been delivered.
The government wants the crucial part of the structure completed within about 30 days, with construction continuing around the clock.
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Two barges could provide rapid emergency relief
A second, faster intervention is also being prepared.
Two approximately 80-metre barges are to be positioned downstream of the cold-water intake and secured to piles on the right bank. They would be placed at an approximately 45-degree angle rather than perpendicular to the shore.
The vessels are intended to act as temporary flow-control structures. According to modelling presented at the briefing, partially sinking the barges could immediately raise the water level by around 10-15 centimetres, while the full deployment of one barge could potentially produce an increase of about 20 centimetres.
The two barges would create a combined diversion structure roughly 160 metres long.
They are expected to be ready for testing from Friday so that they can be used rapidly if the Danube falls below the critical level earlier than forecast.
However, the government regards their use as a last-resort measure. Magyar warned that an uncontrolled barge could create serious problems if it broke free, became lodged in the river or obstructed the plant’s warm-water outlet.
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Construction to continue into the autumn
Preparatory work on the left bank is scheduled to accelerate between 15 and 18 August, including clearing the route and installing geotextile material.
A pontoon structure on the right bank is planned between 17 and 21 August to allow rock to be delivered directly into the riverbed.
Rock placement will then proceed from both sides during late August and early September, with the two sections of the water-raising ridge expected to be joined by around 11 September. Additional reinforcement work is planned to continue into October.
The project is designed ultimately to guarantee a gauge level of around minus 90 centimetres at Paks, which the government says would allow the nuclear plant to operate at full capacity.
Emergency project to cost EUR 16.9 million
The government currently estimates the gross cost of the Paks-Dunaszentbenedek bed sill at HUF 6.165 billion, or approximately EUR 16.9 million at the official 13 August exchange rate.
The figure includes the reconstruction of affected road sections and rehabilitation of the riverbanks.
Funding will come from Hungary’s national emergency reserve, while the budget of the National Directorate General for Water Management will be opened to cover the project.
Magyar said spending would be closely monitored and contractors would be required to account for all expenditure.
The government has also received private-sector offers of assistance. Austria’s Strabag has offered technology, transport and materials free of charge, according to the prime minister, while Hungarian-owned KÉSZ Group has also made an offer.
Magyar criticised major companies associated with the former Fidesz government for what he described as a lack of similar offers.
Full shutdown could cost HUF 50 billion a month
The financial stakes are significantly larger than the cost of the emergency intervention.
According to Magyar, a complete loss of production at Paks would cost the state budget at least HUF 50 billion, or roughly EUR 137 million, every month. That estimate does not include the additional cost to businesses and the wider economy of replacing domestic nuclear generation with more expensive electricity imports.
The prime minister estimated that the water shortage and reduced Paks production are currently cutting around 0.1% from Hungary’s GDP, although he stressed that precise calculations are not yet available.
Maintaining Paks output is particularly important because the nuclear station normally plays a central role in Hungary’s electricity supply. Recent record-low Danube levels have already forced the plant to operate far below its usual capacity.
Nuclear safety limits the available solutions
Government officials said numerous engineering options had been considered with water-management, energy and nuclear experts.
Some were rejected because nuclear safety had to remain the overriding consideration, Magyar said. The government ultimately selected the riverbed sill and possible deployment of barges as what it considers the safest, most effective and most cost-efficient immediate combination.
The National Atomic Energy Office has been monitoring the project since the planning stage, while engineers from the Budapest University of Technology and Economics contributed to the modelling.
The Defence Administration Office is coordinating the numerous state bodies, contractors and military units involved.
Magyar described the situation as the reverse of a flood emergency: instead of protecting infrastructure from too much water, authorities are attempting to maintain sufficient water levels to protect critical infrastructure.
Environmental approvals running alongside emergency work
The accelerated construction has also raised questions about environmental permitting.
The government has classified the situation as an emergency, allowing physical works to begin before all procedures have been completed. Officials stressed, however, that this does not eliminate environmental studies or the requirement to obtain permits.
Hydrobiologists and ecologists have been involved in planning, according to the water-management authority. The environmental authorisation process must begin by the end of September and will examine effects on wildlife and the river ecosystem.
A permanent operating permit for the sill will be possible only if the structure meets the relevant requirements.
Magyar said modelling suggests that the structure would increase Danube levels by no more than around one centimetre during a future flood, and therefore should not significantly increase flood risk.
Paks II and Hungary’s longer-term cooling strategy questioned
The emergency has also revived a broader debate over how Hungary’s nuclear power system should adapt to increasingly extreme river conditions.
Magyar said the government would examine the possibility of installing cooling towers or closed-loop cooling systems. Such investments would be expensive, but he said they could eventually become necessary for the lifetime extension of the existing Paks plant, the planned Paks II expansion, or both.
He also questioned whether the existing environmental and cooling permits for Paks II adequately reflect the river conditions Hungary is now experiencing.
The government is preparing broader climate and water-management strategies, including the “Water into the Landscape” programme, while Magyar said Hungary would seek to make water management a priority during negotiations over the next EU budget.
He also argued that international agreements governing use of the Danube need to be reconsidered because many were drawn up for very different river-flow conditions.
Austria and Slovakia have complied with existing agreements, Magyar said, but the underlying hydrological situation has changed substantially.
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Political dispute over responsibility for the crisis
The prime minister also used Thursday’s briefing to criticise Viktor Orbán’s former government, which governed Hungary for 16 years before Magyar took office in May 2026. Magyar accused the previous administration of failing to prepare sufficient long-term solutions for low Danube levels and of neglecting possible investments such as changes to Paks’s pumping infrastructure.
These were political allegations by the current government rather than findings presented as part of the technical assessment.
Magyar also criticised proposals circulating online, including suggestions involving dredging, blasting or large-scale pumping systems, arguing that some could endanger nuclear safety.
He separately attacked Mi Hazánk leader László Toroczkai over criticism of the decision to shut down Paks turbines, saying nuclear safety could not be compromised for the sake of maintaining electricity generation.
Low Danube levels becoming a long-term energy challenge
The government maintains that the emergency measures will prevent the Paks nuclear power plant from losing all of its generation capacity, but officials acknowledge that there is currently no clear indication of when the Danube will return to substantially higher levels.
That makes the crisis larger than an immediate engineering problem.
The government is preparing a wider energy plan covering wind power, electricity storage and greater diversification of energy sources. Magyar said Hungary needs more capacity to retain and store energy and must ensure that electricity is available from as many domestic and external sources as possible.
For Paks, meanwhile, the coming days remain decisive. The barges are being prepared for immediate use, while construction of the more permanent riverbed sill proceeds around the clock.
If the Danube continues to fall towards the minus 140-centimetre threshold before the interventions take effect, Hungary could still face the first complete shutdown of the Paks nuclear power plant in its more than four decades of operation.
