Patent Number: 043550002
Section: description

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION Referring now to the drawings, and initially to FIG. 1, there is illustrated in schematic form the general arrangement for a nuclear reactor building unit. The unit includes several storage pool and reactor well structures each including passageways 11 for access either to the interior of an individual structure or between adjacent structures. The pool and well structures are designed to provide a safe environment for nuclear fuels and are generally filled with water to isolate the fuels from areas surrounding the nuclear power plant. Accordingly, the access passageways 11 are each provided with a gate 10 to seal off the interior of the particular reactor well or the like. As can be seen in FIG. 2, each gate 10 is a heavy, thick-walled member which is generally congruent in shape to the cross-section of the access passageway 11 of the reactor well wall 12. The gate 10 is supported at one side by a hinged member 13 mounted to the wall 12 whereby the gate 10 may be swung from the closed position illustrated in FIG. 2 to an opened position generally at right angles to the wall 12 to provide unobstructed access to the reactor well interior. In order to securely lock the gate 10 when it is in a closed position, a laterally movable latching member 14 is slidably supported on a ledge 15 formed across the width of the gate 10. A bracket 16 is provided on the wall 12 at the portion thereof facing the swinging end of the gate 10 whereby the laterally movable latching member 14 may be moved partially into the bracket 16 to lock the gate 10. To advantage, the laterally movable member 14 is provided with a rack portion 17 in meshing engagement with a gear 18. The gear 18 is suitably connected to an actuator (not shown) and is rotatable to slide the movable member 14 between unlocked and locked positions. In accordance with the present invention, a lightweight beam structure 19 is provided as a support for a sealing means for the gate 10. To advantage, the beam structure 19 is made from lightweight stainless steel sections and in a typical installation may be approximately 25' high and 4' wide. As is clearly illustrated in FIG. 4, the beam structure 19 comprises a generally U-shaped I-beam 20 defining outwardly facing, continuous channels 21, 22. The U-shaped configuration may be made from several preformed I-beam sections 32, 33, 34 connected together, as for example by welding. A pair of tabs 23 extend one from each the outer ends of the I-beam 20 and each tab 23 includes an eyelet 24. In this manner, the lightweight beam structure 19 may be attached to a hoisting apparatus for lifting and movement about the nuclear plant. A plurality of transverse members 25 extend between the spaced leg portions of the U-shaped I-beam 20. These members 25 provide structural support and also serve as a means for removably attaching the beam structure 19 to the gate 10 as will be described. A plurality of hanger brackets 26 are mounted on the inner side of the gate 10 as, for example, by welding, whereby the beam structure 19 may be supported on the gate 10 by placing the transverse members 25 on the brackets 26. The access passageway 11 of the reactor well is configured such that there is a region of enlarged width at the outermost portion of the passageway 11 so that when the gate 10 is in a closed and locked position, the mounted beam structure 19 is disposed between the locked gate 10 and reactor well wall 12 and within the enlarged region of the passageway 11. Two pair of elongated, continuously flanged tubular sealing elements 27 are mounted along the entire length of the continuous channels 21, 22 such that one pair is disposed in each channel 21, 22 with each sealing element 27 of one pair being in a side-by-side relation to the other sealing element 27 of the pair. The initial or deflated cross-sectional configuration of each sealing element 27 is as shown in FIG. 2 and includes a solid flange portion 28, a neck portion 29 and a hollow, inflatable section 30. As is clearly illustrated in FIG. 2, the above-described arrangement for the channels 21, 22 and sealing elements 27 provides a continuous sealing means around the perimeter of the gate 10 and between the gate 10 and reactor well wall 12. One pair of sealing elements faces the inner surface of the gate 10 and the other pair faces the well wall 12. Thus, upon inflation of the sealing elements, a leak-tight seal may be formed between the gate 10 and well wall 12. The side-by-side arrangement of each pair insures that if one sealing element 27 should become defective, the second element 27 of the pair will maintain the seal. The entire sealing means is easily removable from the gate 10 by simply deflating the sealing elements, attaching a hoisting apparatus to the lifting tabs 23, and lifting the beam structure 19 off the brackets 26. The lightweight, U-shaped configuration provides a structure which is easy to handle and transport within the nuclear power plant while the inflatable sealing elements 27 are operable to provide a highly reliable seal between the gate 10 and wall 12, as will be described in more detail hereinbelow. Referring now to FIG. 3, the sealing elements 27 are shown in an inflated condition whereby the back-to-back elements 27 and the I-beam 20 form a seal extending between the gate 10 and wall 12 and running along the entire perimeter of the gate 10. The tubular inflatable section 30 of the sealing elements 27 may be inflated by any suitable connection (not shown) to a source of air pressure (not shown). For example, an opening may be formed through the lining of the inflatable section 30 for insertion of an air tube connected to the source of air pressure. Such an arrangement is described in the Schroth U.S. Pat. No. 3,984,942 which is hereby expressly incorporated by reference. After the gate 10 is locked, the source of air pressure may be actuated to inflate the sections 30 causing the sealing elements 27 to expand into sealing contact with the gate 10 and wall 12, thereby forming a leak-tight seal between the gate 10 and wall 12. To advantage, the sealing elements 27 are secured within the channels 21, 22 by a series of flange-receiving clips 31. As shown in FIG. 6, the clips 31 are mounted within the channels 21, 22 and are arranged in staggered relation, alternately facing in opposite directions. To mount the continuous sealing elements 27, the element is inserted into the channel 21, 22 by progressively bending the sealing element back and forth between the alternate clips 31 and inserting the flange 28 under the clips 31. For a more detailed description of the alternately facing clip arrangement, reference should be made to the Carlson U.S. Pat. No. 3,397,490. Referring now to FIG. 7, there is illustrated a modification for the sealing means of the present invention. The beam structure 100 comprises a generally U-shaped beam 101 which is T-shaped in cross-section. Thus, the beam structure 100 includes an outwardly extending flange portion 102 for supporting the inflatable sealing elements 103, as for example, by staggered clips 104. In this manner, the flange portion 102 may serve as a locating fin for the beam structure 100. When the structure 100 is lowered into position between the gate 105 and reactor well wall 106, the side areas of the flange portion 102 are guided into longitudinally extending slot-like passages 107 formed in the reactor wall 106 at the periphery of the access passageway 110. This arrangement will facilitate the raising and lowering movement of the beam structure 100 by insuring that the structure does not drift or rotate as it is being moved. In other respects, the sealing means of FIG. 7 is similar to the sealing means of FIGS. 1-6. The beam structure 100 may be supported by the gate 105 or by any other suitable means and the sealing elements 103 are inflatable to form a leak-tight seal between the gate 105 and reactor well wall 106. Of course, the gate 105 is provided with a locking means 108. A further modification of the present invention is illustrated in FIG. 8. A single pair of inflatable sealing elements 103 is mounted on one side of the flange portion 102 with the individual sealing elements 103 being in a side-by-side relation with each other. On the opposite side of the flange portion 102 a pair of solid, continuous sealing strips 109 are securely fastened to the beam 101 with each sealing strip 109 being directly opposite a corresponding inflatable sealing element 103. The sealing strips 109 are arranged to be in a slightly spaced relation to the reactor well wall 106 when the sealing elements 103 are in an uninflated condition. Upon inflation of the sealing elements 103, the expansion thereof will cause the elements 103 to contact the gate 105 and also urge the beam structure 100 away from the gate 105 and toward the interior of the access passageway 110. Accordingly, the sealing strips 109 will be pushed up against the reactor well wall 106 to complete the seal formed between the gate 105 and wall 106 by the sealing elements 103, beam 101 and sealing strips 109. In all its various forms, the sealing means of the present invention provides a highly advantageous structure for insuring a leak-tight seal between the gate and reactor well wall. The unique beam structure is lightweight and easy to handle while forming a seal element supporting means around the perimeter of the gate. The inflatable sealing elements are conveniently mounted by the beam structure between the gate and wall for reliable operation to form a leak-tight seal. Thus, the present invention provides an apparatus highly suitable for utilization in the unique environment defined by a nuclear reactor power plant. It should be understood, of course, that the specific forms of the invention herein illustrated and described are intended to be representative only, as certain changes may be made therein without departing from the clear teachings of the disclosure. Accordingly, reference should be made to the following appended claims in determining the full scope of the invention.