Experience transfer for extending the life of the Cernavodă reactor: Argentinean and Romanian experience on the same project

Argentine state nuclear company Nucleoeléctrica Argentina SA and Romanian operator Nuclearelectrica have signed a Memorandum of Understanding (MoU) envisaging cooperation on a complex project to extend the operating life of the Cernavoda Nuclear Power Plant in Romania

With this agreement, Argentina aims to transform its decade-long expertise in the operation and refurbishment of heavy-water reactors into a commercial service platform on the global market, generating foreign exchange inflows and exporting domestic high technology, while Romania seeks to extend the life of its nuclear plants—the only CANDU reactors in Europe.

Joint CANDU technological basis

The core of this collaboration lies in the fact that both the Romanian Cernavoda plant and the Argentine Embalse plant use the same Canadian technology – CANDU heavy-water reactors with pressurized water. The Embalse plant (capacity 683 megawatts), which entered commercial operation in 1984, has successfully undergone the full life-extension process. After extensive works – which included replacing reactor tubes and steam generators, with a 6 percent increase in the plant's output – Embalse was returned to the grid in 2019 with approval to operate for the next 30 years.

The Romanian plant has two CANDU-6 reactors, each with a capacity of 650 megawatts. The first unit has been in commercial operation since 1996, and Nuclearelectrica's plan is to extend its life to a total of 60 years.

The designed operating life of a CANDU reactor is 30 years, after which a comprehensive reconstruction is necessary. This process requires a complete shutdown, discharge of nuclear fuel and heavy water, as well as replacement of key components in the core itself—including all 480 fuel channels and 960 feed tubes, with inspection of thousands of otherwise inaccessible parts.

This process, which is necessary roughly every thirty years, is very likely one of the key reasons why the CANDU reactor has not achieved more substantial commercial success.

Progress of works in Romania

The block 1 revitalization project at Cernavodă began in 2017 and is currently in the second of three phases. The third, most intensive phase is planned for 2027 to 2029, during which the reactor will be completely shut down to carry out all equipment replacements and recommissioning.

The Argentine government earlier this year defined the export of nuclear services and technology as one of the four key pillars of developing its nuclear sector. At the end of last year, Nucleoeléctrica signed a similar memorandum with the Canadian company Candu Energy Inc (part of the AtkinsRéalis group), thereby positioning Argentina as a key global partner for engineering, technical assistance, and maintenance of CANDU plants around the world.

S.A.