Packaging for transporting and/or storing a set of radioactive materials, the packaging comprising a lateral body extending about a longitudinal central axis of the packaging, as well as a bottom and a removable lid respectively arranged at the axial ends of the lateral body of the packaging, the latter delimiting, with the bottom and the removable lid, a containment chamber for housing the set of radioactive materials, the packaging also including an internal shock-absorber housed in the containment chamber and intended to be arranged axially between the removable lid and the set of radioactive materials, characterised in that the internal shock-absorber includes a single layer of tubes for absorbing shocks by plastic deformation, or a plurality of layers (C1, C2, C3) of tubes for absorbing shocks by plastic deformation, each layer being arranged in a layer plane (P1, P2, P3) orthogonal to the longitudinal central axis of the packaging, the shock-absorbing tubes all having, within the same layer, an annular or substantially annular cross-section from at most three different reference cross-sections, each tube extending along a longitudinal line of the tube and all of the longitudinal central lines of the tubes of the same layer (C1, C2, C3) being inscribed in the layer plane (P1, P2, P3) of the layer concerned, in that the number and the dimensions of the shock-absorbing tubes of each layer are provided such that, in an axial view of the packaging, the ratio between on the one hand the cumulative projected area of all of the shock-absorbing tubes of the layer, and on the other hand the surface area defined internally by the notional circle of smallest diameter in which all of these shock-absorbing tubes are circumscribed is greater than 0.2, and in that within each layer (C1, C2, C3), in axial view of the packaging, the shock-absorbing tubes are transversally spaced apart from one another so that in a transverse direction of each tube, the latter has opposite any other tube of the same layer, a minimum transverse spacing (Emin) greater than or equal to 0.4 * Dext, where "Dext" corresponds to the external diameter of the shock-absorbing tube considered. characterised in that the internal shock-absorber includes a single layer of tubes for absorbing shocks by plastic deformation, or a plurality of layers (C1, C2, C3) of tubes for absorbing shocks by plastic deformation, each layer being arranged in a layer plane (P1, P2, P3) orthogonal to the longitudinal central axis of the packaging, the shock-absorbing tubes all having, within the same layer, an annular or substantially annular cross-section from at most three different reference cross-sections, each tube extending along a longitudinal line of the tube and all of the longitudinal central lines of the tubes of the same layer (C1, C2, C3) being inscribed in the layer plane (P1, P2, P3) of the layer concerned, in that the number and the dimensions of the shock-absorbing tubes of each layer are provided such that, in an axial view of the packaging, the ratio between on the one hand the cumulative projected area of all of the shock-absorbing tubes of the layer, and on the other hand the surface area defined internally by the notional circle of smallest diameter in which all of these shock-absorbing tubes are circumscribed is greater than 0.2, and in that within each layer (C1, C2, C3), in axial view of the packaging, the shock-absorbing tubes are transversally spaced apart from one another so that in a transverse direction of each tube, the latter has opposite any other tube of the same layer, a minimum transverse spacing (Emin) greater than or equal to 0.4 * Dext, where "Dext" corresponds to the external diameter of the shock-absorbing tube considered.