First steel cut for French SNLE 3G deterrent submarine

The first SNLE 3G submarine is due to enter service in the mid-2030s. (Naval Group)

French shipbuilding, support, and services contractor Naval Group has formally commenced construction of the first third-generation nuclear-powered ballistic missile submarine (sous-marin nucléaire lanceur d'engins de troisième génération: SNLE 3G) for the French Navy.

A steel-cutting ceremony was held at Naval Group's Cherbourg shipyard in northwest France on 20 March. The as-yet-unnamed submarine will be the first of a planned four SNLE 3G boats intended to replace the current Le Triomphant-class deterrent submarines from the mid-2030s to ensure that the French Navy can continue to maintain a continuous at-sea deterrent well into the second half of the century.

The Direction générale de l'armement (DGA) is managing the SNLE 3G programme in partnership with the Commissariat à l'Énergie Atomique et aux Énergies Alternatives energy commission. At the industrial level, Naval Group and nuclear group TechnicAtome are working as co-prime contractors: Naval Group is taking responsibility for the submarine design, build, and integration, while TechnicAtome is responsible for the development and production of the new K22 pressurised water reactor.

Naval Group is currently operating under a February 2021 DGA contract covering detailed design and development activity, procurement of major long-lead items, and production of pressure hull and nuclear reactor compartment components for the first SNLE 3G boat. This award, which funds the programme through to the end of 2025, also includes investments to adapt Naval Group's manufacturing facilities to better meet the requirements of the SNLE 3G build programme.

The 20 March event in Cherbourg marked the symbolic first steel cut for the SNLE 3G pressure hull. Production of the main components of the reactor compartment, notably the reactor pressure vessel, is already under way at Naval Group's Nantes-Indret site.