Danube low water prompts shutdown risk at Paks and Cernavoda amid Europe-wide cooling constraints

Hungary: Paks enters advanced Danube low-water stage

Magyar Villamos Művek (MVM), the Hungarian operator, said the Danube level is 28 centimetres below the previous record set in 2018. That earlier record had been one metre below the 100-year minimum water level used in the design of Paks nuclear power plant.

MVM said the plant has already been reducing total output without a safety issue, but noted that while the current extremely low water level and water flow rate would allow sufficient water to cool the units, the suction level required for pumps is higher than the water level and is expected to continue decreasing.

MVM said Danube low-water conditions are divided into four stages based on intake measurements and that the plant is currently in stage 3. It added that forecasts show a realistic chance of a stage 4 event, under which all units would have to be shut down and then cooled. It stated that implementing a complete shutdown must be carried out within 24–72 hours, based on forecasts that change several times a day.

For cooling during a full shutdown, MVM said 5 cubic metres of water per minute would be needed, compared with 100 cubic metres per second for operating units. It said standby and reserve pumps are in place and that Paks is prepared to keep units in a safe condition during extremely low water conditions lasting for weeks. Restarting would occur in stages once the appropriate water level is reached, depending on the level.

MVM attributed the record-low Danube levels to climate-change-related hydrology, saying low water has persisted all year, and to deepening of the river bed. It also pointed to preparatory work to lower intake pipes, saying that within a few years the plant should be able to continue production even with a lower water level than the current one.

Romania: Cernavoda unit 1 shut; unit 2 may be next

In Romania, Nuclearelectrica announced that Cernavoda unit 1 was being shut down and disconnected from the National Energy System due to the unprecedentedly low level of the Danube caused by severe drought.

The company said the shutdown followed forecasts from the National Institute of Hydrology and Water Management and described the action as preventive to protect nuclear safety and the reliability of facilities, with “no impact on nuclear safety, personnel or the environment.”

It later indicated that unit 2 was likely to be shut down, but then updated its position: unit 2 would remain online after analysis of operating parameters and equipment carried out during the night of 29 to 30 July 2026 found that operating parameters allow continued operation in safe conditions.

Nuclearelectrica added that shutdown of unit 2 may still be necessary at any time considering the current situation and hydrological forecasts. It said Cernavoda is Romania’s only nuclear power plant, with two 650 MWe Candu reactors that generate about a fifth of national electricity.

Broader context: heatwave cooling-water controls across Europe

The heatwave’s impact is extending beyond the Danube basin. In France, EDF temporarily took Bugey unit 3, Chooz unit 2 and Golfech 2 offline to comply with regulations on cooling water discharges, while eight other reactors operated at reduced power.

The measure was described as an environmental protection requirement to avoid discharging too much hot water into rivers already warming due to the heatwave.

In Switzerland, the two units at Beznau were temporarily shut down, or operated at lower power over recent weeks due to high temperatures in the River Aare.

Serbia advances nuclear programme planning with EDF studies and capacity support

Agreement and study programme

Serbia is moving forward with its nuclear programme foundation work following an agreement with EDF, under which the programme’s early technical studies are being delivered and expanded.

Minister of Mining and Energy Dubravka Đedović Handanović said the country intends to draw on EDF’s “knowledge, experience and resources” as Serbia lays the foundations for nuclear energy.

Serbia’s government said the initiative follows a milestones approach recommended by the International Atomic Energy Agency. EDF delivered the Preliminary Technical Study on the Peaceful Use of Nuclear Energy in March, identifying 19 key steps across three phases: phase 1 covers feasibility and steps needed to decide on launching a national nuclear programme; phase 2 includes selection of a nuclear reactor type, contracting and construction; and phase 3 is when construction takes place.

In October 2024, Serbia’s Ministry of Mining and Energy awarded a contract to EDF, with French engineering consultancy Egis, to conduct the preliminary technical study on the potential use of nuclear power in Serbia. EDF is now due to produce three more studies within phase 1, while the remaining 14 studies are expected to be considered with “various international companies that have the necessary experience.”

EDF delivered the Preliminary Technical Study on the Peaceful Use of Nuclear Energy
Phase 1 includes feasibility and decision-making steps; phase 2 covers reactor type selection and contracting and construction; phase 3 is construction
EDF is due to produce three more studies in phase 1, with 14 additional studies to be assessed with other international companies

Workforce and organisational capacity

A key component highlighted by Serbian officials is human resources development. The minister said the most important part of the project relates to developing a human resources development strategy, described as a prerequisite for launching a national nuclear programme.

Đedović Handanović emphasised that human resources are central to developing nuclear programmes and said Serbia’s task is to create a base of engineers and other personnel able to manage nuclear facilities responsibly and professionally in the future.

Capacity building support is also part of the effort. The French Development Agency (AFD) has provided a grant of EUR500,000 (USD576,000) to support building professional and organisational capacities in Serbia, aimed at improving the knowledge and experience of personnel involved in the nuclear programme.

Human resources development strategy is a key prerequisite for launching a national nuclear programme
AFD grant: EUR500,000 (USD576,000) to support professional and organisational capacity building
Goal stated by the minister is to complete all studies by the middle of next year to enable an informed decision on further nuclear programme development

Decision timeline and longer-term outlook

The Serbian minister said the goal is to complete all studies by the middle of next year to enable an informed decision on further development of the nuclear programme.

She also noted that Serbia must be ready in an institutional, regulatory and professional sense for the choice of technology, adding that Serbia could get its first nuclear power plant after 2040.

World Nuclear Association publishes roadmap to expand nuclear investment and close supply-chain financing gaps

Scale of capital need and finance architecture

The World Nuclear Association has published the first part of a World Nuclear Investment Guide, described as a “Roadmap to Mainstream Finance: The Path to Scale Nuclear Energy.” The guide is intended to define conditions for governments, industry and financial institutions to support investment at the scale required by nuclear power’s growth projections.

The association points to a potential increase in global capacity to 1,446 GWe by 2050 when “all operable, under construction, planned, proposed, and potential reactors are combined,” compared with 403 GWe from operable reactors today. It estimates the required investment totals USD6 trillion up to 2050, covering the sector from mining through reactor construction and including decommissioning and storage costs.

The guide frames the challenge as building an “investment architecture” that enables capital to flow at scale, including into the nuclear fuel cycle required to deliver new generation capacity. It does not characterise the issue primarily as a shortage of capital for mainstream financiers, but as gaps in market readiness and long-term policy commitment. It highlights the need for “financial frameworks, standardised instruments, comparable market data, and track records” to support confidence in assessing and pricing nuclear risk.

Conditions for mainstream finance and an example of financing barriers

The roadmap identifies six conditions needed to make nuclear “a mainstream asset class”: institutional support; business standardisation; priceable risk and reward; market remuneration frameworks; and supply chain capacity and maturity transformation mechanisms.

It also illustrates a financing barrier for development-stage activities. The guide says financing for activities such as licensing, engineering, site preparation and early procurement “typically has no revenue stream,” which means it “falls outside standard project finance structures,” leaving developers to rely on corporate balance sheets, vendor risk-sharing, or early-stage catalytic capital.

Supply-chain funding gap and instruments cited to close it

Beyond plant-level financing, the roadmap highlights upstream capital needs for the supply chain. It states that “manufacturers and component suppliers need working capital, tooling investment and capacity expansion funding well ahead of confirmed orders,” explicitly distinct from financing of the plant itself.

To address this supply-chain financing gap, the guide points to export credit agencies, trade finance and supplier-focused guarantee instruments as “central to closing this gap.” It says closing both development-stage and supply-chain gaps is a precondition for the transition described in the roadmap.

Advisory input and next publication milestone

World Nuclear Association says the guide was developed with leaders from the nuclear and finance sectors through a Nuclear Investment Guide Advisory Board and Task Force, and is intended to close knowledge gaps and build a common language between governments, industry and investors.

The guide’s full publication is due on 9 September at the Finance Summit being held as part of World Nuclear Symposium in London.