Patent Number: 042591546
Section: claims

1. A nuclear reactor containment structure comprising a closure casing, a pedestal within said closure casing for supporting a pressure vessel, a diaphragm floor dividing said closure casing into a drywell and a pressure suppression chamber and supported at its inner peripheral end by said pedestal and at portions near the outer peripheral end of the floor by vertical columns, said outer peripheral end of the diaphragm floor being free from contact with the inner surface of said closure casing, said diaphragm floor including structural steel beams radially extending between said pedestal and said closure casing, and a plurality of shear keys secured to the inner surface of said closure casing and associated with the respective outer ends of said steel beams to permit the vertical and radial movements between said steel beams and said closure casing but restrain the circumferential movement therebetween, said diaphragm floor further including concrete layers disposed between the respective adjacent steel beams. 2. A nuclear reactor containment structure as set forth in claim 1, wherein said concrete layers have the substantially same thickness as the height of said steel beams to form substantially flat upper and lower surfaces of said diaphragm floor. 3. A nuclear reactor containment structure as set forth in claim 1 wherein said diaphragm floor includes a steel plate layer positioned below the concrete layers. 4. A nuclear reactor containment structure as set forth in claim 1 wherein there is provided means for connecting an inner peripheral end of said diaghragm floor to said pedestal. 5. A nuclear reactor containment structure as set forth in claim 3 wherein there is provided means for connecting an inner peripheral end of said diaphragm floor to said pedestal. 6. A nuclear reactor containment structure as set forth in claim 4 wherein said connecting means includes anchor bolts. 7. A nuclear reactor containment structure as set forth in claim 4 wherein said connecting means includes anchor plates. 8. A nuclear reactor containment structure as set forth in claim 5 wherein said connecting means includes anchor bolts. 9. A nuclear reactor containment structure as set forth in claim 5 wherein said connecting means includes anchor plates. 10. A nuclear reactor containment structure as set forth in claim 1, wherein an annular elastic sealing element is provided between the outer peripheral end of said diaphragm floor and the closure casing. 11. A nuclear reactor containment structure as set forth in claim 1, wherein said structural steel beams are H-shaped structural steel beams. 12. A nuclear reactor containment structure as set forth in claim 1, wherein said concrete layers comprise two outer layers of unreinforced concrete, for insulating heat, and a layer of reinforced concrete sandwiched therebetween. 13. A nuclear reactor containment structure as set forth in claim 12, wherein said concrete layers have the substantially same thickness as the height of said steel beams to form substantially flat upper and lower surfaces of said diaphragm floor. 14. A nuclear reactor containment structure as set forth in claim 1, wherein the diaphragm floor includes a steel plate layer positioned on the upper side of the structural steel beams. 15. A nuclear reactor containment structure as set forth in claim 11, wherein steel plates are positioned to bridge across the upper side of the lower flanges of the H-shaped structural steel beams.