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DCNS Started Upgrading the Last French Navy SSBN Le Téméraire for the new M51 Ballistic Missile

Naval Industry News - France
DCNS Started Upgrading the Last French Navy SSBN Le Téméraire for the new M51 Ballistic Missile
As part of the "IA M51 programme" (Regular Overhaul / adaptation for the M51 missile) Le Téméraire, the last of the three French nuclear-powered ballistic missile submarines (SSBN) to benefit from this upgrade, was transferred on Wednesday, 7 December, from Ile Longue (French for "Long Island", base of the French Strategic Oceanic Force) to dock 8 of the naval base in Brest, where this large-scale work is carried out with DCNS as prime contractor.
Le temeraire SSBN French Navy M51 upgrade DCNS 1French Navy Le Triomphant-class SSBN Le Téméraire. Picture: DCNS
After preparation operations on Ile Longue, the M51 / regular overhaul (ROH) adaptation work starts at dock 8 of the naval base in Brest. For the next 18 months, DCNS teams will be carrying out the adaptation work for the M51 ballistic missile and the extensive refit maintenance operations involved in the major technical shutdown.

Involving nothing but superlatives (140 km of cable to be fed through, 60 tons of engine seatings to be welded, 1.3 million parts to be supplied), the ROH and adaptation operation for the M51 missile is being supervised by DCNS with the French defence procurement agency (DGA) and the Fleet Support Service (SSF) as joint client. The objective is to carry out the third and final ROH / adaptationprogramme after those on Le Vigilant and Le Triomphant. Le Terrible, the latest in the series of new-generation of SSBNs has been equipped with the M51 missile from the outset.

In addition to the complete maintenance programme, carried out every 9 years on this class of submarine, and the adaptation to accommodate the new M51 missile, the navigation and combat systems will be upgraded. Because of their size (138 metres long, 12,500 tons), onboard technologies at the cutting edge of scientific progress, and the constraints relating to their use in operations, these submarines are among the most complex systems produced in the world.
Le temeraire SSBN French Navy M51 upgrade DCNS 2French Navy Le Triomphant-class SSBN Le Téméraire. Picture: DCNS
A workforce of 1,100
The scope of the work will require an increase in the headcount on the site. As a result, 1,100 people will be taking part in the programme during the peak of activity in dock 8, with an organisation in three shifts, six days a week. "This complex project illustrates the expertise of DCNS, as prime contractor and project supervisor. In addition to our own teams on the sites in Brest, Ruelle and elsewhere, we are coordinating the work of some 45 companies in the region around Brest and the West of France that have been called upon to carry out with us the 4 million hours of work required by the overhaul, all in compliance with our safety, deadlines and quality of work specifications," explains Michel Drévillon, director of the IA M51 programme.

As part of its Progress Plan and objectives to increase safety at work, DCNS has launched various performance measures in order to optimise the rhythm of the three eight-hour shifts, peaks in activity and interventions on the site. Finally, thanks to feedback from the ROH / adaptation work on the SSBN Le Triomphant, on this project, DCNS has further strengthened its ties with its subcontractors: a shared performance plan has been set up to meet the challenge of carrying out the full ROH / Adaptationprogramme in 1 month less than the last.
Zumwalt DDG 1000 San Diego 2
French New Generation SLBM M51. Picture: French MoD
Comment by Navy Recognition
The M51 is fitted today on board three of the four new generation SSBNs of the French Navy (Le Triomphant class). The transition of the entire French Navy's strategic oceanic force fleet to the M51 missile is expected by the end of the decade.

The M51 is the new generation intercontinental SLBM gradually replacing the M45 since 2010. Each missile carries six to ten independently targetable (MIRV or Multiple Independently targeted Reentry Vehicle) TN 75 thermonuclear warheads. TN 75 started getting replaced with the new Tête nucléaire océanique (TNO or oceanic nuclear warhead) warheads last year (2015). These new warheads are reported to be maneuverable (MARV or Maneuverable Re-entry Vehicle) in order to avoid potential ballistic defenses. The TNO has a yield that is estimated to be greater than or equal to the yield of the TN 75 warhead, 150 kilotons of TNT (kt) with a CEP (circular error probability) of 150 meters. The warhead's design and functionality were validated through simulation, particularly with DAM's Tera 100 supercomputer, Megajoule laser, and radiographic equipment. The M51 range is reported to be close to 10,000 Km.