Third generation SNLE propulsion
nuclear steam supply systems

Development and production of the four nuclear steam supply systems (NSSS) on board the SNLE 3G rocket-launching nuclear submarines. TechnicAtome is also in charge of the support system (tooling, training) and the fuels of the NSSSs.

The rocket-launching nuclear submarines constitute the oceanic component of the French nuclear dissuasion force. The SNLE 3G will take over from the SNLE 2G, type Le Triomphant, when they are withdrawn from active service scheduled for around 2035 for the first of them.

Main services

  • Development of the submarine NSSS: design and dimensioning studies, layout of installations, definition and qualification of the NSSS equipment and systems, definition and qualification of the nuclear fuels
  • Safety studies and production of official documentation to obtain operating authorizations (in particular the safety report)
  • Production of the NSSS of the four submarines: procurement of the equipment, assembly of the NSSS, production of the instrumentation and control and carrying out of the startup tests
  • Development and production of the support system including in particular the core loading and unloading tools and the training platforms for the training of the National Navy personnel

© Naval Group

Particularities of the SNLE 3G NSSSs

In line with the compact NSSSs of the K15 family which equip the SNLE 2G, type Le Triomphant, the NSSSs of the SNLE 3G programme constitute a link between the NSSSs of the Barracuda programme, which was lower in power, and the K22 NSSSs of the future nuclear-propelled aircraft carrier, which is significantly greater in power.
They comprise a certain number of significant innovations compared with the Barracuda NSSSs designed mainly around 2010, innovations which are intended to be loaded into the K22-type NSSSs.

© Naval Group

Main stages:

  • 2006 – 2010 : Prospective study phase/first rough layouts
  • 2011 – 2012 : Highly Synoptic Pre-Project Phase (APTS)
  • 2012 – 2016 : Synoptic Pre-Project Phase (APTS)
  • October 2017 – december 2020 : Detailed Pre-Project Phase (APD) consolidating the specifications of the NSSS, proposing a definition and validating the overall performance thereof. These studies enable the sufficient level of guarantee to be acquired to launch the production phase of the Programme (development, industrialisation, manufacture), including the assessment of the preliminary safety report by the Safety Authorities
  • Février 2021 : Décision de lancement de la réalisation par l’État, et notification du marché de Réalisation
  • Timeline 2035 : Delivery of the first submarine of the SNLE 3G generation