Patent Number: 042279682
Section: description

SPECIFIC DESCRIPTION FIGS. 1 and 2 show a prestressed substantially cylindrical cast metal pressure vessel 1, hereinafter referred to as the reactor vessel, which has a central chamber 2 receiving a helium-cooled high-temperature nuclear reactor using ball-shaped nuclear fuel elements (not shown). Such reactors are conventional in the art. The reactor vessel 1 has a copper plate 1a, a bottom plate 1b and a cylindrical wall structure 1c which is traversed by vertical stressing cables 3. The stressing means for the horizontal stressing of the individual receptacles is not shown in these Figures. It should be understood that the pressure vessels of the present invention can be composed of cast iron or cast steel blocks which are assembled together while the cover 1a and the plate 1b may likewise be composed of segments or sectors held in interfitting and tight relationship. Such structures are known in the art. Referring now to FIG. 1A, it will be seen that a typical pressure vessel, whether used as the central pressure vessel or one of the satellite vessels, as represented at 101 in FIG. 1A, can have a cover 101a which rests upon the wall structure 101c and is clamped by nuts 103a thereagainst, the nut being threaded onto the stressing cable 103. Corresponding nuts 103b engage the opposite end of the stressing cable 103. The cable 103 passes through a bore 101d in the wall structure 101c and through corresponding registering bores in the cover 101a and the base 101b. The prestressing cables 103c which extend around the vessel in horizontal planes provide the inward and individual prestress previously mentioned. In a partial circle around the reactor vessel 1 there are provided a plurality of angularly equispaced component vessels 4 which are likewise formed from prestressed cast material as pressure vessels and which are likewise substantially cylindrical (see the foregoing discussion as to FIG. 1A). Here the vertical prestressing is applied by tension cables 5 which pass through the cover and the bottom plates of the component vessel 4. Horizontal prestress is effected via cables 103c in the manner already described and as shown, for example, in FIG. 1B. Each component vessel 4 communicates with the reactor vessel 1 via a horizontal gas passage 6 which can be provided with a pair of coaxial conduits one of which delivers gas to the component vessel while the other conducts the gas back into the reactor vessel. Preferably, the hot gas from the high-temperature reactor traverses the inner of the coaxial conduits while the returning gas, relatively cool, traverses the outer conduit of the coaxial conduit system. All of the horizontal gas passages 6 lie in a common horizontal plane and extend radially with respect to the vertical axis of the assembly. The horizontal plane of the passages 6 lies in the lower portion of the cylindrical wall 1c of the reactor vessel 1. In the region of the horizontal gas passages 6, the reactor vessel 1 is provided with a plurality of vertical planar surfaces 7 which together form a polygonal cross section for the reactor vessel and lie generally along tangents to circles centered on the axis of the reactor vessel. Thus in the region of the plane mentioned previously, the reactor vessel has a polygonal cross section. The vertical planar surfaces 7 are so arranged that some of the surfaces 7a lie at right angles and are pierced by the horizontal radial gas passages 6. The component vessels 4 in the same region are also provided with vertical planar surfaces, i.e. at least three and preferably five such surfaces angularly adjoining one another. One of the planar surfaces of each of these component vessels, shown at 8a, lies directly against the corresponding surface 7a and is coextensive therewith, being also perpendicular to the gas passage 6 which communicates between this component vessel and the reactor vessel 1. The gaps 9 between the individual component vessels 4 are filled only in the region of the vertical planar surfaces 7 and 8 into a complete circular disk with support blocks 10 of grey cast iron. The support blocks 10 are as shown hollow and hence constituted by cast webs. The support blocks 10 abut the vertical planar surfaces 7b of the reactor vessel 1 between the surfaces 7a and against the lateral planar surfaces 8b of the component vessels 9. As a result, in the region of the horizontal plane mentioned previously, the pressure vessels 1 and 4 form together with the support blocks 10 a disk-shaped compound body 11. A horizontal prestressing member 12 as shown generally in FIG. 1 and FIG. 2 in which it is constituted as a band but as cables 11a and 11b in FIG. 1B, prestresses the composite disk inwardly. The manner in which the peripheral prestressing member 11a, 11b or 12 passes around the disk can be seen from FIG. 2. The vertical prestressing of the individual vessels by means of the tension cables 3 and 5 or 103 is thus not effected in any way by the support blocks 10. The component vessels 4 preferably receive the steam-generating heat exchangers and any waste-heat recovery system in the manner described. FIG. 3 shows an embodiment of the invention in which the hollow support blocks 10 do not form a single composite body but rather form two composite bodies represented at 13 and 14 respectively above and below the gas passage 6. Each of the composite bodies 13 and 14 can be stressed inwardly by a respective band 12 or set of cables 11a, 11b.