Naval Technology

Nuclear ignition on board Barracuda submarine, as Tourville undergoes first divergence

The Third Barracuda-class submarine has undergone first divergence, triggering an initial nuclear reaction in the Tourville boiler room.

When the nuclear reaction began on 24 April, France’s Tourville Barracuda submarine reached a significant milestone.

Currently being tested and completed in Cherbourg, the Tourville is the third nuclear attack submarine in the Barracuda series.

Equipped with nuclear propulsion, similar to their predecessors, the Barracuda-class submarines offer significant enhancements in stealth and range. They surpass the previous generation in speed, endurance, and versatility, featuring capabilities such as deploying special forces and striking distant land targets with naval cruise missiles.

The start-up of the nuclear boiler room, called "divergence", was carried out by the Naval Group and TechnicAtome teams with the support of the submarine's weapons crew. It consists of triggering for the first time a controlled nuclear reaction in the core of the ship's nuclear propulsion reactor.

The Tourville nuclear boiler room, developed under the project management of the Atomic Energy and Alternative Energies Commission (CEA), is now the host of a nuclear reaction that will go on to power the submarine throughout its lifetime.

The first divergence is a major milestone before sea trials in mid-2024.

For the management of the onboard nuclear reactor project, the CEA relies on TechnicAtome for the design and construction of the reactors, and on the Naval Group for the implementation of associated main capabilities and the integration of the reactors aboard the submarines.

The French Defense Procurement Agency (DGA) has commissioned six submarines under the Barracuda programme to modernise the French Navy's nuclear attack submarine fleet by 2030. This new generation will replace the Rubis-class submarines that have been in service since the 1980s. The first two submarines of this class, Suffren and Duguay-Trouin, entered active service in June 2022 and April 2024, respectively.

The last three submarines of the Barracuda program (Grasse, Rubis and Casabianca) are currently at different stages of construction, and their deliveries will take place until 2030.