External blast risks

INB 50 (basic nuclear facility) safety reassessment

Study of buildings behavior under blast load

The study is carried out in the context of the INB 50 safety reassessment. It deals with the behavior of two buildings under external blast :
• Study of the structure behavior under the influence of a pressure wave, using a finite element modeling with a non-linear behavior of the concrete material. The 3D numerical modeling is made of shell elements for walls and slabs, and beam elements for beams and columns. A modeling of the reinforcement bars is also carried out. Non-linear behavior laws are used for concrete and steel, in order to reflect concrete cracking under traction, concrete plastification under compression, et reinforcement bars plastification taking into account their strain hardening.
• Assessment of the minimal incident blast wave that could lead to the ruin of the buildings : assessment of the most disadventageous pressure wave shape, identification of the critical structural areas, assessment of the maximal pressure that could be withstood by each of the critical structural areas.
• Retrofitting studies of the builing to ensure its mechanical strength under a pressure wave.
• Technical support during the case evaluation by IRSN (French Institute for Radiological Protection and Reactor Safety) and ASN (Nuclear Safety Authority).

General view of the mesh
General view of the mesh
Deformation of an Eigen mode
Deformation of an Eigen mode
Blast wave of the incident pressure
Blast wave of the incident pressure
Displacements
Displacements
Variation of the base torsor
Variation of the base torsor
Ground vertical stress
Ground vertical stress