[en] The goal of this thesis is to study the neutron propagation by reflection from lacunar medium interfaces. The most efficient method to calculate this type of propagation is to use the concept of albedo. Actual version of NARCISSE code uses a simple formulation of angular differential albedos and so, can only treat single reflections. Multiple reflections treatment needs the knowledge of neutron spectrum after reflection. This energetic information is contained in double angular and energy differential albedos. The first step of this study consists to generate these albedos for various materials. Several methods have been tested and the Monte Carlo method was retained. A new estimator has been developed and validated in the Mote Carlo transport code TRIPOLI-4. It computes, during the simulation of the neutron history, the angular and energy reflection probability at each collision site. The second step consists to generate an interpolation scheme and albedo libraries for various materials. A new version of NARCISSE was developed to use these libraries and the interpolation module. Spectrum and dose rates comparisons were made between codes to validate these albedos. The neutron propagation by multiple reflections can be studied now, by using this new version of Narcisse. (author)