Patent Number: 042591562
Section: summary

The invention relates to a device for coupling pipelines in pressure vessels of nuclear reactors, preferably the pipelines of the feedwater manifold or distributor, and which more particularly, has a first line or piping section sealingly extending through the pressure vessel-housing wall and fastened thereto, and a second line section sealingly connected to the first line section and constructed, especially, as a ring-shaped distributor line or manifold, as well as a core container with a core-container cover fastened in the pressure vessel and steam separators forming, with the core-container cover, a structural unit. Such a device has become known heretofore, for example, from the article entitled: Steam-Water Separators and Steam Dryers, by G. Pollak in the periodical "Konstruktion", 1971, Book 11, Page 442, FIG. 1, wherein, however, no particulars are otherwise provided or recognizable details presented concerning how the connection or coupling of both line sections of the feedwater manifold is effected. Since the steam separators or cyclones are fastened to the core-container cover, a series of problems is produced: The pressure vessel and the first line section therewith, on the one hand, as well as the pressure-vessel installations (core container, cyclones) and the second line section therewith, on the other hand, exhibit varying thermal expansions, especially in axial and in radial direction, during operation, and especially for load variations as well as during start-up and shutdown. The line connection must thereby maintain the tight sealing thereof. When inserting and removing the pressure vessel-installations, a reliable and rapid coupling and uncoupling operation of both line section with a minimum of tool expense is desired. As many parts of the core-container installations as possible, also the feedwater manifold, should be removable so that an inspection of these removed parts as well as an inspection of the remaining reactor pressure vessel per se may be permitted. During operation, vibrations occur in the coolant circulatory loop of the pressure vessel; the connection or coupling of both line sections must therefore also be carried out so that it is vibration-proof. It is accordingly an object of the invention to provide a pipeline coupling device of the foregoing type which takes the foregoing requirements into account. More specifically, it is an object of the invention to provide a coupling device for a feed-water manifold, for example, between a first and a second line section thereof, which is of such construction that it is movable by thermal inducement with good sealing action and is vibration-proof. Furthermore, in order to effect engagement or release of the coupling device, no actuation of screw or clamping closures is required. With the foregoing and other objects in view, there is provided, in accordance with the invention, in a device for coupling pipelines in a pressure vessel of a nuclear reactor having a first line section sealingly extending through the pressure vessel-housing wall and fastened thereto, and a second line section sealingly connected to the first line section, as well as a core container fastened within the pressure vessel, the core container having a cover, and steam separators forming, together with the core-container cover, a structural unit, the second line section being also included with the core-container cover and with the steam separators fastened to the cover in the structural unit and, when the pressure vessel is opened, the second line section together with the core-container cover being liftable out of the pressure vessel and being re-insertable into the pressure vessel, the first and the second line sections being in mutual contact at coaxial sealing surface portions formed thereon at the sealed connecting location thereof, the sealing surface portions being placeable into nominal location of sealing connection thereof through the weight per se of the structural unit of the core-container cover the steam separators as well as through bracing forces for the core-container cover, the bracing forces being oriented in axial direction of the pressure vessel, and means for affording relative motion, dependent upon thermal expansion, the sealing surface portions within a predetermined tolerance range without impairing sealing action thereof. In accordance with another feature of the invention, the coupling device includes ball-cylinder seat means forming an axial slide fit for bringing the sealing surface portions of the first and the second line sections into mutual engagement. In accordance with a further feature of the invention, the cylinder seat of the ball-cylinder seat means comprises an angle ring having inwardly directed flanks at the underside thereof held against a support flange of an upwardly directed mouthpiece of the first line section and outwardly directed flanks surrounding coaxial sealing surface portions of the ball seat of the ball-cylinder seat means of an upwardly directed union of the second line section. In accordance with an added feature of the invention, the angle ring has a retaining flange at the outer periphery thereof spring-elastically braced with the support flange of the mouthpiece of the first line section in a manner that relative movement in at least one of radial and tangential directions between the second line section and the angle ring with slight tilting disposition of the angle ring within the predetermined tolerance range is afforded. By the predetermined tolerance range there is meant the greatest deflections of thermally induced movement occurring during operation. As a rule, such deflections have a value of a few millimeters. In accordance with an additional feature of the invention, the flanks at the underside of the angle ring are formed with spherical contact surfaces engaging the flange of the mouthpiece. In accordance with yet another feature of the invention, the second line section has conically inwardly running axial guide pins and the angle ring-retaining flange is formed with corresponding guide bushings for engaging the guide pins whereby the union of the second line section is centered. In accordance with yet a further feature of the invention, the coupling device includes a sheetmetal apron applied to the support flange of the upwardly directed mouthpiece of the first line section for shielding the angle ring-sealing surface portions from the pressure-vessel wall. In accordance with yet an added feature of the invention, the upwardly directed mouthpiece has a tube part, and the tube part of the upwardly directed mouthpiece, the angle ring and the union of the second line section are flattened in radial direction forming a slot-like cross section. In accordance with yet an additional feature of the invention, the coupling device includes ball-cylinder seat means forming an axial slide fit for bringing the sealing surface portions of the first and the second line sections into mutual engagement, the cylinder seat of the ball-cylinder, seat means being formed as an angle ring, the sealing surface portions of the first and the second line sections, as well as the angle ring, having outer layers of material selected from plating material and weldment material. In accordance with a concomitant feature of the invention, there is provided a method of coupling pipelines in a pressure vessel of a nuclear reactor with the foregoing coupling device, which comprises sealingly extending the first line section through the housing wall of the pressure vessel and fastening the first line section to the housing wall; forming a structural unit within the pressure vessel of a second line section together with installations of the pressure vessel; when the pressure vessel is closed, holding the installations in position against stops disposed in the pressure vessel by means of releasable bracing means; and holding the coupling device of both the first and the second line sections in contact position thereof through a force-lock of the bracing means so that, upon releasing the bracing means and removing the installations and upon inserting the installations and arresting the bracing means, automatic uncoupling and coupling, respectively, of the coupling device are effected. Other features which are considered as characteristic for the invention are set forth in the appended claims. Although the invention is illustrated and described herein as embodied in a device for coupling pipelines in reactor pressure vessels, preferably the pipelines of the feedwater manifold, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.