Our design office, with experience of several hundred projects in the nuclear sector (civil and military), supports you with all of your structural problems in order to guarantee the durability of your structures in line with nuclear safety requirements.


Services range from the design of a facility based on a comprehensive knowledge of nuclear regulations (ETC-C, RCC CG, RCC CW, safety regulator standards, specific standards of large clients), via optimisation of structures using advanced methods validated by the regulator, technical support on projects for their presentation to the authorities, to the study of decommissioning operations.

Our expertise in advanced studies applies to various fields

Support for all actors in the sector:

  • Operators
  • Research institutes
  • Safety authorities
  • Design managers
  • Construction firms

Multiphysics expertise:

  • Linear and non-linear seismic behaviour
  • Seismic probabilistic safety assessments
  • Consequences of severe attacks (plane crash, internal/external explosions or fire, tornados)
  • Assessment of ageing effects

Involvement at every stage in the life of facilities and equipment:

  • Design of new facilities, including parametric studies according to safety requirements
  • Design review of facilities for approval by regulators
  • Assessment of existing facilities
  • Definition of technical solutions to extend the lifespan of facilities (reinforcement, use of innovative methods, tests)


  • Development, in partnership with EDF, of a worldwide unique constitutive law, able to take into account multiphysics effects (water, drying, prestressing, creep, thermal and cracking effects) on ​​concrete containment structures in order to predict leakage flows through the reactor container (Vercors project).
  • Development of structural digital twins for infrastructure enabling almost real-time monitoring
  • Participation in research projects to design the nuclear structures of the future

Récemment récompensé par la Société française de l’énergie nucléaire, Xavier Ursat, Directeur de DIPNN, EDF et ancien président de la Sfen a salué le travail des équipes Sixense necs lors de la remise du Grand Prix :

« Je tiens vraiment à saluer l’engagement de necs, sa constance dans ses apports, la qualité de l’opération avec les donneurs d’ordres, l’innovation scientifique mise en place et le caractère extrêmement concret des résultats qui nous fait évidemment gagner beaucoup en capacité de justification de nos bâtiments.»