Patent Number: 
Section: claims

1. Storage device for storing and transporting nuclear fuel assemblies, said device comprising a plurality of adjacent compartments, each having a lateral wall and being capable of receiving a nuclear fuel assembly, said lateral walls being made using notched structural units that are stacked and crisscrossed, wherein each unit comprises:two spaced-apart flats made of a neutrophage material;an intermediate structure situated between the flats, said intermediate structure comprising:two bars arranged between said two flats without being mechanically jointed to said flats; anda plurality of spacers in contact with said two flats, arranged in a spaced apart manner along the length of said two bars, each spacer being rigidly jointed to the two flats at its two ends, respectively, said two bars orthogonal to the direction of stacking of the structural units,wherein said intermediate structure of each structural unit includes two steel bars spaced apart from each other by spacing means that includes the plurality of spacers and wherein each of the plurality of spacers are penetrated through by fasteners joining them rigidly to the two flats of the structural unit. 2. Storage device of claim 1, characterised in that each notched structural unit has an overall H-shaped cross section, the two flats constituting the two sides of this H, respectively. 3. Storage device as claimed in claim 1, characterised in that each compartment has a lateral surface delimiting it, said lateral surface consisting at least partially of the flats of the notched structural units forming the lateral wall of said compartment. 4. Storage device as claimed in claim 1, characterised in that said neutrophage material is an alloy containing boron, and in that said intermediate structure is at least partially made of steel. 5. Storage device as claimed in claim 1, characterised in that said intermediate structure of each structural unit is made so as to form a single part. 6. Storage device of claim 5, characterised in that said intermediate structure of each structural unit is rigidly assembled on the two flats. 7. Storage device of claim 5, characterised in that said intermediate structure of a given structural unit is held in a stacking direction with the help of the structural units arranged in a crossed fashion in relation to the given unit and being directly adjacent to the given unit in the direction of stacking. 8. Storage device of claim 1, characterised in that, for each structural unit, said spacing means are rigidly assembled to the two flats of said structural unit, and in that one of the two steel bars is situated on one side of the spacing means and the other one of the two steel bars is situated on the opposite side of said spacing means, in relation to a stacking direction of the structural units. 9. Storage device of claim 8, characterised in that each bar of a given structural unit is held in the stacking direction with the help of the spacing means, on the one hand, and, on the other hand, with the help of the structural units, which are arranged in a crossed fashion in relation to said given structural unit, and which are directly adjacent to it in the direction of stacking. 10. Storage device as claimed in claim 8, characterised in that bars of each structural unit are arranged perpendicular to the direction of stacking. 11. Storage device as claimed in claim 2, characterised in that each compartment has a lateral surface delimiting it, said lateral surface consisting at least partially of the flats of the notched structural units forming the lateral wall of said compartment. 12. Storage device as claimed in claim 7, characterised in that for any given layer of structural units, the structural units of the next following and third following layers are in contact in pairs with the edges of the flats situated between cut-outs provided on these flats, and the structural units of the given layer and the second following layer are likewise in contact in pairs with edges of the flats situated between the cut-outs provided on these same flats. 13. Storage device of claim 1, wherein said fasteners are screw/nut assemblies.