Romania is moving ahead with one of Southeast Europe’s most important nuclear investments: the refurbishment of Unit 1 at the Cernavodă nuclear power plant. In July 2026, the European Investment Bank approved an €800 million loan for the project, providing significant public financing for efforts to keep the reactor operating for another 30 years.
Unit 1 entered commercial operation in 1996 and typically supplies around 10% of Romania’s electricity. Extending its operating life would preserve a major source of low-carbon, dispatchable generation at a time when coal capacity is being phased out and renewable output is becoming increasingly variable. It would also help maintain the technical expertise, workforce and supply chains associated with Romania’s CANDU nuclear fleet.
The EIB financing represents an important part of the investment, but not the project’s full cost. Refurbishment requires the replacement or upgrading of major reactor systems, extensive safety improvements and preparations for a second operating cycle. Such work involves a complex and carefully planned outage, meaning that cost control, scheduling and project execution will be critical, even though refurbishment generally carries less construction risk than developing an entirely new nuclear site.
The strategic rationale for extending Unit 1 is strong. Romania’s two Cernavodă reactors normally account for around one-fifth of national electricity generation. Their stable output complements rapidly expanding wind and solar capacity while reducing the country’s exposure to imported fossil fuels. Nuclear life extension can therefore support both decarbonisation and energy security without requiring Romania to wait for a new generation of nuclear projects to materialise.
However, the Danube emergency of August 2026 exposed an important vulnerability. Record-low water levels forced one Cernavodă reactor offline and threatened the cooling supply of the remaining unit. Authorities responded by removing a rock obstruction, dredging the riverbed and constructing a temporary dike from rock-filled barges. The measures increased the local water level by around four centimetres and extended the remaining unit’s operation by at least nine days.
The incident broadens the definition of nuclear resilience. Reactor safety and fuel security remain fundamental, but future nuclear investment must also account for heat and water stress. Cooling-system design, water intakes, river-basin forecasting and operating limits will increasingly need to reflect more extreme hydrological conditions. A plant can be a major source of low-carbon electricity while still being exposed to climate-related risks.
The regional implications are significant. A prolonged outage at Cernavodă can tighten electricity supply not only in Romania but also across interconnected Southeast European markets, particularly when drought is simultaneously reducing hydropower generation. This correlation strengthens the case for batteries, demand response and stronger interconnections alongside nuclear refurbishment. Firm generation remains essential, but no single technology can be considered completely firm under every climate scenario.
For other nuclear markets in Southeast Europe, Romania’s experience offers an important benchmark. Bulgaria, Slovenia and Croatia all face strategic decisions concerning the extension of existing nuclear capacity or the development of replacement projects. Refurbishment can generally be faster and less capital-intensive than new nuclear construction, but its benefits depend on regulators confirming that both technical and climate-related vulnerabilities are adequately addressed.
Cernavodă Unit 1 is therefore more than an ageing reactor receiving new equipment. It represents a test of whether Southeast Europe can preserve its existing low-carbon generation base while adapting critical infrastructure to a more challenging operating environment. The €800 million EIB commitment demonstrates confidence in the project, while the Danube crisis has raised the bar for the resilience that the refurbished reactor will need to deliver.
