SSBN 3G: a key program for long-term deterrence

Why and when was the SNLE 3G program launched? 

Claire: The purpose of the SSBN 3G program is to develop and build four SSBNs to replace the Le Triomphant-class SSBNs as they are withdrawn from active service, the first of which will be 40 years old in 2037. The continuity of the oceanic component of French nuclear deterrence, unbroken since the first patrol of the Le Redoutable in 1972, is at stake. Deterrence is key to our security and the SSBNs contribute to this thanks to their ability to disappear into the oceans and launch missiles loaded with nuclear warheads. The SNLE 3G program therefore lies at the heart of the role of the French Defence Procurement Agency (DGA), but also of Naval Group, as it aims to provide the French Navy with one of its main means of power.

Stéphane Obled: The development of such a complex object – 1 million components, 20 million hours of work – requires planning far in advance. Reflections on the successor of Le Triomphant began even before the last second-generation SSBN entered into active service and. This continued up until the launch of the program in February 2021, with an initial contract including the basic design studies for the submarine, the launch of long lead-time supplies, the construction of the first parts of the hull and reactor for the first third-generation SSBN, and the adaptation of the industrial facilities to the specific needs of the third-generation SSBN. The second contract began in November 2025. This covers the continuing upgrade of the means of production, the detailed design of the submarines, the launch of all supplies, and the construction of the first third-generation SSBN, whose name, L’Invincible, was unveiled last March by the French President.

How have these vessels evolved? 

C.: The DGA, in its strategic capacity, has defined their characteristics keeping in mind that their performance will have to respond to future threats.

Third-generation SSBNs will have a higher level of discretion than those of the second generation thanks to an innovative acoustic coating and an attenuated magnetic signature. Their detection capabilities will also be increased, thanks to improved sonar, in particular.

S. O.: The third-generation SSBNs will also be larger than their predecessors, therefore allowing their evolution throughout their life cycle just as in the case of second-generation SSBNs.

How is the program organised and what is its schedule?

C.: The DGA is project owner for the program along with the French Alternative Energies and Atomic Energy Commission (CEA). Naval Group is the prime contractor for submarines, alongside TechnicAtome for the nuclear reactors. Our collaboration dates back to the creation of the DGA by General de Gaulle in 1961 on the basis of deterrence, a shared project that transcends us and has enabled us to work together in harmony for more than sixty years. The program also draws on the know-how of leading equipment manufacturers – Thales, ArianeGroup and Safran – and the metalwork industry – Aubert & Duval and Framatome – and relies on about 500 companies of all sizes from the defence technological and industrial base throughout France. The DGA supports them and ensures the maintenance of the industrial capacities needed to enable France to retain its sovereignty.

S. O.: The SNLE 3G program mobilises the highest level of skills across all the group’s departments and entities, on all its sites. Expectations are very high in many areas, such as discretion, safety and cybersecurity. Our teams can nevertheless rely on the architecture of the second-generation SSBN and on the industrial expertise acquired thanks to the Barracuda program.

In 2026, the internal whole warship preliminary design review (PDR) will take place, followed by the basic design review chaired by the customer. The rest of the schedule provides for the launch of L’Invincible in 2036, its delivery at the end of 2037 and then that of the following units every five years. Naval Group is ready to take on this project, which challenges us to go above and beyond!

Textual transcription

La découpe de la première tôle du premier SNLE 3G sur le site Naval Group de Cherbourg le 20 mars 2024.