CIGEO – Thermo-hydro-mechanical behaviour

CIGEO – Thermo-hydro-mechanical behaviour

THM (thermo-hydro-mechanical) behaviour modelling near storage cells for high-activity (HA) waste.

Projet : 

Deep storage consists of storing nuclear waste in a deep geological formation which is able to assure in the very long term containment of radionuclides in the very long term. ANDRA is responsable for designing and building such a centre: CIGEO Industrial centre for geological storage.

Expected waste volume (industrial scenario provided by waste producers, end of life of the current nuclear fleet): approximately 70 000 m3 of MA-VL waste (of which approximately 60% already exist) and 10 000m3 of HA waste (of which 30% already exist). Footprint of the outdoor installations: approximately 300 hectares.

Link between the surface and the bottom: Four 500 m deep wells and a 5 kms double decline (inclined tunnel).
Underground installations:

  • Linking galleries – approximately 100 kms
  • MA-VL storage cells: 20 kms
  • HA storage cells: 200 kms

 

Final total footprint of the underground installations: approximately 15 km2

Mission : 

In the framework of this project, ISL was awarded a study of the thermo-hydro-mechanical behaviour of a HA storage cell. The study necessitated implementing a model capable of taking into consideration different phenomena :mechanical (creep, damage, anistropy), thermal and hydraulic as well as their coupling, made possible thanks to the implementation of a new behavioural law under ANSYS (User Programme Features in Fortran).

  • The evolution of the massif’s damaged area  
  • Procedures for through-wall loading of the lining
  • Evolution of the void between the lining and the massif
  • Simulations carried-out with the help of this model have allowed us to describe and answer questions about:

  • Incertitudes and their impact

Le projet
Pays/région : 
France
Client: 
Andra – Agence nationale pour la gestion des déchets radioactifs
Période : 
2011-2012