Patent Number: 
Section: claims

1. Package (100) comprising storage packaging (1) as well as a confinement canister (3) for irradiated fuel, the storage packaging (1) comprising:a lateral body (2) which extends around a longitudinal axis (12) of the packaging and which includes an internal surface (22) which delimits a housing cavity (4) wherein the canister (3) is placed,a detachable head cover (6) closing the housing cavity (4) at an upper end (2a) of the lateral body (2),a packaging base (8) closing the housing cavity (4) at a lower end (2b) of the lateral body (2), andat least three assemblies (15) forming guide rails for the canister (3), each assembly (15) forming a guide rail for the canister in the cavity and being mounted on the lateral body and protruding at least partly into the housing cavity (4) from said internal surface (22) of the lateral body (2),wherein each of the at least three assemblies (15) includes an impact shock absorbing element designed to absorb the shock, by plastic deformation, of a lateral impact between the packaging (1) and the confinement canister (3),wherein in any transverse section plane through the packaging (1) and through the canister (3), the ratio of the surface area of the canister (3) delimited by its external surface to the surface area of the cavity (4) delimited by its internal surface (22) is greater than 0.8,wherein the at least three assemblies (15) are circumferentially spaced from each other and arranged around the cavity (4),wherein at least one assembly (15) of the at least three assemblies (15) comprises a radially internal portion forming a rail (24), andwherein the shock absorbing element of the at least one assembly (15) is arranged between the rail (24) and the lateral body (2), at least partially within a recess in the lateral body (2), the recess being defined by a bottom wall and two opposite lateral walls of a housing (20). 2. Package according to claim 1, wherein each of the at least three assemblies (15) extends along the direction of the longitudinal axis (12) over a length (L) corresponding to at least 70% of the height (H) of the housing cavity (4) along this same direction. 3. Package according to claim 1, wherein each of the at least three assemblies (15) is parallel to the longitudinal axis (12). 4. Package according to claim 1, wherein the at least three assemblies (15) are spaced circumferentially apart from each other on the interior surface (22) of the packaging body (2). 5. Package according to claim 1, wherein the impact shock absorbing element for each of the at least three assemblies (15) is made of aluminum or of one of its alloys. 6. Package according to claim 1, wherein in a transverse sectional plane of the at least one assembly (15), the ratio of the surface area of the portion (15a) of the at least one assembly (15) located in the housing (20) to the surface area of the housing (20) is less than 0.9. 7. Package according to claim 1, wherein the rail (24) of the at least one assembly (15) is provided with a low-friction coating (26). 8. Package according to claim 1, wherein the rail (24) of the at least one assembly (15) is made of steel. 9. Package according to claim 1, wherein the rail (24) and the impact shock absorbing element of the at least one assembly (15) are connected to each other by a connection which uses complementary shaped parts (36). 10. Package according to claim 1, wherein:the rail (24) of the at least one assembly (15) is firmly attached to the lateral body (2) at one end, andthe rail (24) of the at least one assembly (15) is arranged so that a remaining length of the rail from the one end is free to move in translation along the longitudinal direction of the rail (24), relative to the shock absorbing element, up to the other end of the rail (24). 11. Package according to claim 1, wherein the canister (3) contains irradiated fuel rods, preferably grouped together within one or more nuclear fuel assemblies. 12. Package according to claim 1, wherein the guide rail of each of the at least three assemblies (15) is adapted to permit sliding of the canister (3) relative to the guide rail.