Charles de Gaulle: a closer look at the replacement of the “boilers”

17 July 2023 Defense Naval Group Surface ships Fleet services News

Having entered the Vauban dock at the naval base in Toulon on 16 May, the Charles de Gaulle has been placed in dry dock for a period of scheduled maintenance. Under the supervision of the Fleet support service (SSF), the teams from Naval Group’s Services Department are maintaining and upgrading its systems. This includes the replacement of the rear engine's distillation and demineralisation systems, more commonly known as “boilers”, used to produce fresh water on board.

Conducted between two major technical stops, the aim of mid-cycle docking (MCD) for the aircraft carrier is to restore its full potential and upgrade certain systems. As a result, the 2023 MCD for the aircraft carrier Charles de Gaulle comprises a significant amount of work to be carried out within a tight deadline, to allow the flagship of the French Navy to return to its operational cycle in a timely manner.


A large-scale operation within a packed schedule

The 2023 MCD program comprises no less than 1,900 though-life support lines and more than twenty major modifications, including the hospital refit, replacement of the TACAN Ng, renovation of areas dedicated to naval staff and crew living quarters, as well as the replacement of two of the vessel’s four boilers. These seawater distillation systems enable fresh water to be provided for the ship’s crew, as well as nuclear grade distilled and demineralised water for the production of steam, which is essential for the vessel to function. With an equivalent volume – each weighing 9.2 tonnes unladen and measuring 4 metres x 3 metres x 2.70 metres – these new boilers will each increase the quantity of fresh water produced per day from 130 to 180 tonnes.


A European collaboration, a team effort

Under Naval Group’s supervision, the production and subsequent qualification of this design-critical equipment is the result of European collaboration between Naval Group and its supplier Alfa Laval and its subsidiaries. Alfa Laval was chosen as the supplier, specifically for its compliance with lead times and the availability of qualification resources. Specified in France, designed in Denmark, produced in Germany and qualified full-scale on a test bench in northern Denmark, these two new boilers were technically accepted on 6 June 2023 at a contractual hold point, a decision that gave the go-ahead to dismantle the two boilers for replacement.

At Naval Group, the design and integration of these two new boilers involves teams from a number of sites:

  • Nantes-Indret: product specifications, purchasing, functional engineering and fluid integration engineering, arrangement and operation studies
  • Brest: platform integration studies and integrated logistics support
  • Angoulême-Ruelle: development of the control and supervision system
  • Toulon: for the methods, tool design and modular integration project on board the aircraft carrier.


Unwavering commitment

“With the customer, our partners and all employees on the group’s various sites, this project, which is a first – never have boilers of this size been replaced on a vessel in service – is currently on schedule thanks to teamwork and unwavering commitment at every stage. With the notification of this order dating back to late May 2022, qualification tests took place just one year later. In addition, the integration of such volumes into an existing environment poses a challenge for both the engineering teams entrusted with design and the site teams responsible for integration. Heavy and complex handling and assembly work on board awaits the teams from Toulon this summer - again with a tight timetable. They will be joined by teams from Indret for mechanical assembly,” says Laurent Sevellec, Platform Program Package Manager at Naval Group. Connections will be performed in October, followed by tests rounding off this flagship 2023 MCD operation.