Concelex, a leading Romanian construction company, has been awarded a EUR 49.8 million contract by Korea Hydro & Nuclear Power (KHNP) for the construction of several technical facilities and administrative offices, as part of the Cernavoda Nuclear Power Plant Unit 1 Refurbishment Project, for Nuclearelectrica. The works are scheduled to begin in Q1 2026 and will be completed by the end of 2027.
“Being selected for this project is a strong confirmation of our capabilities in the nuclear energy sector and underscores KHNP’s confidence in our ability to deliver complex works to the highest standards of quality and safety. After two projects at the Dry Storage for Burnt Fuel facility at Cernavoda, one completed and one in progress, we are proud to continue contributing to Romania’s strategic energy infrastructure. This new contract allows us to demonstrate once again that Concelex can handle complex, high-standard projects where safety, precision, and reliability are paramount”, said Catalin Visan, Deputy CEO, Concelex.
As part of the refurbishment program for Unit 1 of the Cernavoda Nuclear Power Plant, Concelex is delivering an extensive package of buildings, platforms, and infrastructure works for KHNP. The project includes operational and administrative facilities, logistics areas, electrical transformer substation, yarding services, road works and access control facilities. The scope also covers fire protection water tanks with pumping stations, systems for the relocation of existing utility pipelines and cable routes, groundwater monitoring installations, and the development of internal circulation areas for personnel, equipment, and materials. In parallel, Concelex is implementing complete utility networks, security and surveillance systems. Together, these works ensure the safe, efficient, and uninterrupted execution of the refurbishment program while meeting the stringent operational and safety requirements of a nuclear facility.
The refurbishment of Unit 1 is a cornerstone for Romania’s nuclear energy strategy. Concelex holds certifications from the National Commission for Nuclear Activities Control (CNCAN) for nuclear construction, fabrication, and supply activities. These certifications confirm compliance with strict national and international safety standards and robust quality management systems, ensuring that all works meet the highest requirements for nuclear safety and reliability.
Founded in 1994, Concelex is a leader on the Romanian construction market, with nationwide coverage and proven expertise in complex projects. The company provides integrated construction solutions, from buildings and urban infrastructure to critical infrastructure works, serving both public and private sectors. With a growth strategy focused on continuous investment in innovation, modern technologies, and team development, and with a strong emphasis on professional ethics and integrity, Concelex reported a turnover of 1.26 billion lei in 2024. Today, the company employs approximately 1,000 people and manages over 300 active construction sites.
The Cernavodă Nuclear Power Plant (CNE Cernavodă) continues to stand as the most critical asset in Romania’s energy infrastructure. Providing approximately 20% of the nation’s electricity, the facility remains at the center of the country’s decarbonization strategy and its ambition to become a regional energy hub in Southeast Europe.
Technological Foundation: The CANDU System
Operating with two units, Cernavodă remains the only nuclear power plant in the European Union utilizing CANDU (Canada Deuterium Uranium) technology. Unlike the more common Pressurized Water Reactors (PWR), the CANDU design uses natural uranium as fuel and heavy water as both a moderator and a coolant.
One of the primary technical advantages of this system is the ability to refuel the reactors while they are still online. This “on-power refueling” capability allows the plant to maintain an exceptionally high capacity factor, often ranking among the most efficient nuclear reactors globally in terms of continuous uptime.
The Refurbishment of Unit 1
The year 2026 marks a pivotal phase for Unit 1, which is approaching the end of its initial 30-year design life. Nuclearelectrica, the state-owned operator, is currently in the advanced stages of preparing for a major refurbishment project.
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Objective: To extend the reactor’s operational life by an additional 30 years.
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Scope: The process involves the replacement of fuel channels, pressure tubes, and calandria tubes, alongside a comprehensive modernization of the control systems.
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Timeline: The physical shutdown for refurbishment is scheduled to begin in the coming years, representing one of the largest industrial projects currently underway in Romania.
Expansion: Units 3 and 4
To meet the European Union’s 2030 and 2050 climate goals, Romania has accelerated the development of Units 3 and 4. This expansion project aims to double the plant’s nuclear capacity, adding approximately 1,400 MW of low-carbon electricity to the national grid.
In early 2026, the project is characterized by strengthened international partnerships, particularly with the United States, France and Canada. These alliances focus on financing frameworks and the procurement of long-lead equipment required to bring the two new units into operation by the start of the next decade.
| Project Phase | Estimated Impact | Technical Goal |
| Unit 1 Refurbishment | Life extension to 2060 | Structural Integrity & Safety |
| Units 3 & 4 Expansion | 40% of National Power | Decarbonization |
| Nuclear Fuel Chain | Full Autonomy | Supply Chain Security |
Safety and Environmental Oversight
Operating under the strict supervision of the National Commission for Nuclear Activities Control (CNCAN) and international bodies such as the International Atomic Energy Agency (IAEA), Cernavodă adheres to rigorous safety protocols.
Environmental monitoring stations located around the Danube River ensure that thermal and radiological impact remains well within legal limits. The plant’s “safety first” culture is supported by continuous training programs and periodic “stress tests” designed to simulate extreme external events, ensuring that the facility remains resilient against modern challenges.
Socio-Economic Importance
Beyond the electricity grid, the Cernavodă NPP is a vital economic engine for the Dobrogea region. It provides thousands of highly skilled jobs and supports a vast domestic supply chain, ranging from the nuclear fuel plant in Mioveni to specialized engineering firms across the country. As Romania transitions away from coal-fired power plants, the nuclear sector provides the “baseload” power necessary to stabilize a grid increasingly reliant on intermittent renewable sources like wind and solar.
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