Modernization of Cernavoda nuclear power plant continues, enabling a further 30 years of operation

Nuclearelectrica has announced the completion of a key step in the modernization of Unit 1 at Cernavoda, Romania’s only nuclear power plant. The plant operator has completed pouring the foundations for a temporary intermediate-level radioactive waste storage facility, which will be a key part of the infrastructure needed to modernize the plant. The modernization project began in 2017 and is expected to enter its third and final phase next year.

Romania currently has just one nuclear power plant: Cernavoda, with two CANDU 6 heavy-water reactors. With an installed capacity of more than 700 MWe, they provide around 20% of the country’s electricity generation. The original 30-year operating licence for Unit 1 expires next year, so Nuclearelectrica has been working on its modernization for several years. The project is intended to extend the plant’s operation by a further 30 years.

The plant’s CANDU 6 reactors are pressurized heavy-water reactors originally designed to operate for 30 years. Following a major refurbishment, however, they can operate for a further 30 years. The process involves replacing key reactor components, such as steam generators, pressure tubes and calandria tubes. The large horizontal vessel contains 480 fuel channels, through which high-temperature coolant flows. Each channel is fitted with two end fittings, allowing the fuel bundles to be isolated and replaced without shutting down the entire reactor.

New temporary storage facility is key to the modernization

During the modernization, all the fuel and heavy water will be removed from the reactor and separated from the rest of the plant. The work includes inspecting thousands of components, including those that cannot be accessed while the reactor is operating, and replacing all 480 fuel channels and 960 feeder tubes. According to World Nuclear News, the new temporary intermediate-level radioactive waste storage facility will enable the handling, processing and temporary storage of waste from both the modernization of Unit 1 and the long-term commercial operation of the plant’s two units.

"The completion of the first concrete pour for infrastructure needed to modernize Unit 1 is as significant as the first concrete pour in the construction of the unit. After 30 years of operation in compliance with high nuclear safety standards and with world-class performance in terms of capacity factor, Unit 1 will continue operating for a further 30 years from 2030 thanks to the modernization program," said Cosmin Ghita, CEO of Nuclearelectrica.

Modernization support under scrutiny by the European Commission

The extensive modernization of the plant’s first unit is linked to financial support from Romania. The European Commission recently launched an in-depth investigation into Romania’s public support plan to assess whether the proposed measures comply with EU state aid rules.

According to the Commission, extending Unit 1’s operation for a further 30-year cycle is important for ensuring the long-term availability of low-carbon electricity. The project is also intended to strengthen security of electricity supply in Romania and contribute to the European Union’s decarbonization goals.