François Cortial, 2020 winner of the Réaumur medal

08 February 2021 Innovation Human ressources Story

François Cortial joined Naval Group in January 1987 and is now a senior Metallurgy-Welding Expert and group Welding Coordinator within the Technical and Innovation department (DTI). As such, in addition to the R&D projects to which he is assigned, François is not only involved in all programmes on the issues of choice of materials and processes, but also provides his expertise to external manufacturers. In December, the French Society for Metallurgy and Materials, SF2M (Société Française de Métallurgie et de Matériaux) awarded him the Réaumur medal.

The Réaumur medal is a prestigious award given every two years to distinguish a French or foreign figure whose work has had significant consequences in the fields of durability, assembly or adhesion involving several materials.

What is your background?

I joined Naval Group (the site of Nantes-Indret) in January 1987 after a PhD in physics then an 18-month mission in Gabon with the Geological and Mining Research Bureau (BRGM) as part of my military service. This was when the Charles-de-Gaulle and new-generation ballistic missile nuclear submarines (SSBN) programmes were beginning. At the site of Indret, I developed the physical metallurgy division, i.e. the entity that, within the Laboratory for the study and control of materials (Laboratoire d’Etude et de Contrôle des Matériaux - LECM), now the Centre of expertise for naval equipment and structures (Centre d'Expertise des Structures et Matériaux Navals - CESMAN), carried out studies on materials and their behaviour in production and in service. This was a huge and formidable playing ground! Having since held various positions, I now work on all programmes – still in the field of materials and their implementation processes – from the upstream selection and validation phases through to manufacture and expert appraisals, both internally and in conjunction with our contracting authorities (French Defence Procurement Agency - DGA, French Atomic Energy Agency - CEA, Division of Military Applications - CEA DAM) and nuclear reactor (TA) project management. I also offer my expertise to external players such as DGA, Altran, EDF or Alstom in the context of legal affairs.

What are the highlights of your career?

There are quite a few! I would say the R&D work carried out to acquire and master new techniques such as electron beam welding, for which we developed the Indret hypermachine; the first developments in additive manufacturing and, in particular, the Wire Arc Additive Manufacturing (WAAM) technique for the production of large 3D metal parts which recently culminated in the manufacture of the propeller of the Andromeda tripartite minehunter. I also contributed to the integration of the numerical simulation of welding (SNS), now used on some of the group’s sites, and which represents a source of great help for manufacturing! And one of the most important achievements has to be the development of the all-stainless steel pressuriser for the Barracuda and third-generation SSBN (SNLE3G project) reactors.

What has motivated you throughout your career? What advice would you give to those who follow in your footsteps?

What has fascinated me all these years is seeing the changes in materials and processes following the choices we made, in particular for nuclear reactors, and passing on and sharing this knowledge both in-house and with the public (2,500 articles read, more than 50 publications and more than 270 quotes). It's a long-term affair. Ages ago, I adopted the maxim “What we understand belongs to us” (André Malraux), where knowledge is the key to the richness of life, whatever the field. To those in positions of power, I would say that you have to be patient and trust engineers for their research work; they must have the freedom to be fully involved.