Patent Number: 048511846
Section: description

Referring now to the figures of the drawings in detail and first, particularly, to FIG. 1 thereof, there is seen a reactor building 1 of a pressurized water reactor including a steel safety containment 2, which is a so-called secondary shielding in the form of a sphere having a diameter of 50 meters, for example. The upper portion of the sphere 2 is enclosed by a hemispherical roof portion 3 of the reactor building 1. Below the equator of the sphere, the reactor building is in the form of a vertical cylinder 4 extending to a base plate 5 of the reactor building, which is sunk into soil 6. In a construction which is in the form of heavily reinforced concrete, the thickness D of the reactor building wall 3, 4 is 2 meters, for example. This assures that aircraft striking the reactor building 1 will be unable to do serious damage, which could lead to rupturing of the safety containment 2 enclosing the radioactive components. A so-called valve room or fixture chamber 10, which includes valves or fixtures for shutting off fresh-steam lines leading out of the safety containment 2, is connected to the outside wall 4 of the reactor building 1. Since these valves or fixtures have to be protected from destruction, walls 11 of the valve room or fixture chamber 10 which, for instance, are of block-like form, are at least as thick as those of the reactor building 1. In a typical rectangular building, for example, the emergency supply or feed building of a reactor plant has edges and corners, like those of the valve room or fixture chamber, which represent exposed regions in case of impact. The upper outer corner 12 of the valve room or fixture chamber 10 is double-layered in a region 14, according to the invention. An outer shell 16 extends parallel to an inner shell 15, which has a shape approximately equivalent to that of the original wall 11 and has half the wall thickness thereof, the shells being spaced apart by the thickness of the shell or layer 15, forming a hollow space 17. The outer shell 16 is formed of concrete reinforced with steel fibers or filaments and is thus virtually homogeneously resilient. As FIG. 1 clearly shows, the outer surface 18 of the shell 16 protrudes beyond the surface or plane 19 of the wall 11 by approximately one-half of the original wall thickness, or in other words one meter beyond the plane 19 of the wall 11. The hollow space 17 has three parts due to the fact that it is subdivided by two supports 20 and 21. Rigid expanded plastic in the form of a filler material having a damping action, is accommodated in the hollow space 17. The result of this structure is that if loads are brought to bear on the exposed wall region of the corner 12 from the outside, forces can be transmitted into the valve room or fixture chamber 10 and from it into the reactor building 1 only after attenuation. In the embodiment of FIG. 2, the corner 12 is again provided with a double-layered wall region 14. However, the outer shell 16 in this embodiment is only supported by a single support 23, resulting in a hollow space 17 having two chambers. The hollow space 17 contains metal mesh bodies acting as the damping filler material However, the chambers in the hollow space 17 can also be in the form of prefabricated thin-walled molded articles, without being filled with damping material. As shown in FIG. 3, at the corner 12 of the valve room or fixture chamber 10, the inner shell 15 of the double-layered wall region 14 has practically the same wall thickness as the wall 11, although it has an outer rounded portion 24. The outer shell 16 is raised beyond the outer rounded portion 24, although without an internal support, resulting in a single-chambered intermediate space 17. In the embodiment illustrated in FIG. 4, the reactor building 1 is double-layered in a region 25 of a roof 26, which forms a corner 27. In this embodiment, an inner shell 28 of the double-layered region 25 is reduced to one-half the original thickness of solid walls 29. An outer shell 30 has a rounded portion parallel to the inner shell 28 which is in alignment with the outside of the walls 29. A hollow space 31 is again filled with damping material. Despite the "weakening" of the wall in the region 25 , sufficient resistance to penetration from the outside is obtained. In addition, external forces that are capable of engaging the exposed corner 27 are diminished, so that only slight acceleration forces are triggered in the interior of the reactor building 1. In the embodiment illustrated in FIG. 5, a region 35 of the reactor building 1 is shown at the level of an internal ceiling 36, on which components 37 are supported. For instance, the ceiling 36 encloses a room 38 having electrical systems, represented by cable lines 39. An outer shell 40 of the double-layered region 35 is rounded in shape, so that it protrudes convexly beyond the surface of the reactor building 1. Once again, the intermediate space 41 contains a filler material. FIG. 6 shows that the reactor building 1 can also be double-layered over a greater height in a region 50 in the vicinity of the ceiling 36. As a result, both the ceiling 36 as well a ceiling 51 located below it are protected. An outer shell 52 of fiber-reinforced concrete, together with an inner shell 53 of steel-reinforced concrete, contain two hollow spaces 54 and 55 bordering on one another and containing a damping material. A support 56 located between the hollow spaces 54 and 55 is dimensioned in such a way that no significant forces can be transmitted if there is a direct action from outside, because the inner shell 53 has the greater resiliency when the load is imposed. In the embodiment illustrated in FIG. 7, the reactor building 1 is protected in the vicinity of a corner 60 and a load-bearing ceiling 61 located below it, by prefabricated building elements. A building element 63 associated with the corner 60 has a structure with a rectangular cross section adapted to the corner. Two layers or shells 64 and 65 are both formed of steel fiber-reinforced concrete that is very tough. A hollow space 66 therebetween contains a filler material. The building element 63 is seated sufficiently firmly on the reactor building 1 merely by virtue of its own weight. At that location the building element 63 forms a damping protective layer, which prevents impact strains from being induced into the building 1 upon external action exerted upon the exposed point. A building element 70 associated with the ceiling 61 covers the attachment of the ceiling 61 to a vertical concrete wall 71. The building element is engaged in a corresponding recess 73 with a dovetail-like protrusion 72 at the ceiling 61. A gap 75 remaining after the insertion can be filled up in order to increase strength and to attain a form-locking connection of the building element 70. A form-locking connection is one which is connects two elements together due to the shape of the elements themselves, as opposed to a force-locking connection, which locks the elements together by force external to the elements. However, other fastenings of the building elements 63, 70 to the reactor building 1 are also conceivable.