Several approximations occur during a numerical simulation: physical e ects mapy be discarded, continuous functions replaced by discretized ones and real numbers replaced by finite-precision representations. The use of the floating point arithmetic generates round-o errors at each arithmetical expression and some mathematical properties are lost. The aim of the numerical verification activity at EDF R&D is to study the e ect of the round-o error propagation on the results of a numerical simulation. It is indeed crucial to perform a numerical verification of industrial codes such as devel- opped at EDF R&D even more for code running in HPC environments. This paper presents some recent studies around the numerical verification at EDF R&D