IRSN, Institut de radioprotection et de sûreté nucléaire

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Computer codes

P²REMICS software

P2REMICS is a digital software tool for simulating explosions in industrial facilities. The software calculates the formation of explosive atmospheres, deflagration phenomena and propagation of the shock waves generated. The explosive cloud may contain a mixture of gases or a suspension of fi ne dust particles.




Physical models


P2REMICS simulates 3D, incompressible (formation phase of the explosive atmosphere) or compressible (deflagration and propagation of shock waves) turbulent and reactive flows. Turbulence can be handled by statistical models (RANS), large eddy simulation (LES), or by hybrid models which combine both methods. To simulate deflagration in large-scale buildings, P2REMICS offers explicit monitoring of the flame front, requiring a coarser spatial discretisation than the resolution of the primitive conservation equations of reactive fluid mechanics. These equations are used to interpret smaller scale experiments using fine models, particularly large eddy simulation. P2REMICS validation is based on a large number of comprehensive analytical tests, some of which were conducted by IRSN partners (as part of the ICARE ENACCEF or INERIS EXJET programmes).




Digital schemes


P2REMICS is based on the CALIF3S software components library for fluid mechanics, which offers a set of coherent and essentially original algorithms ensuring stability and precision for all flow regimes, from incompressible to highly compressible. Spatial discretisation, based on staggered mesh schemes, is used to simulate premises with complex geometries using structured or unstructured meshes, refined locally if necessary.




Implementation, pre- and post-processing and portability

CALIF3S is based on the PELICANS platform. Both these tools were developed at IRSN and distributed under an open source software licence. PELICANS has its own HMI and can interface with pre- and post-processing tools such as GAMBIT, Gmsh or GMV, ParaView and FieldView. It features libraries of parallel linear solvers for digital simulations with several million meshes. Portability of this software architecture is supported across LINUX, SOLARIS, WINDOWS and MAC OSX.




Figure 1:
Jet disrupting a stable stratification; this type of situation is encountered in a loss-of-coolant accident scenario, where releases at the break can remix the hydrogen largely present in the upper part of the reactor containment.
In terms of volume: vorticity norm – Left plane: velocity norm – Back plane: concentration of lightweight component.






Figure 2:
Flame propagating rapidly in a mix of hydrogen and air, trapped in an axisymmetric test section. Burnt gases are shown in red, fresh gases in blue and the lines represent the isovalues of the pressure field. Combustion generates a shock wave on the front of the flame, which propagates and reflects from the walls.








To develop P2REMICS, IRSN established a network of external collaboration partners, primarily French universities and CNRS laboratories. It also receives strong scientific support in the fields of modelling, turbulence, gas and dust combustion and digital analysis.

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Collaborative space

​A collaborative space is dedicated to P2REMICS at the adress:

Involved IRSN laboratory

Presentation sheet

Example of simulation

Further information



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