| 摘要 |
964, 051. Handling devices for use in nuclear reactors. GENERAL DYNAMICS CORPORATION. July 19, 1962 [Aug. 2, 1961], No. 27097/62. Heading G6C. [Also in Division B8] A transfer device for lifting nuclear fuel elements &c. comprises a grapple having a lower body portion, supported on an upper body portion so as to permit limited transverse movement of the lower body portion, a plurality of grapple hooks movably carried in the lower portion, and grapple hook actuating means on said lower body portion. Referring to Fig. 2, the mechanism includes two basic movements, extension and retraction of telescopic tubes 48 and 60 by means of a motor 44 and suspension cables 46, and rotation of guide tube 40 by means of a worm and wormwheel 52 which causes the entire mechanism to rotate within housing 34. Automatic rotation of the lower portion of the grapple head is provided which will rotate it an equal and opposite amount to the rotation of the guide tube; thus a fuel element may be removed from the core, moved radially within the plenum chamber (Fig. 1), and simultaneously moved to a different angular position (when viewed in plan) without altering the axial orientation of the fuel element. A further compensatory motion is automatically provided which raises and lowers the telescopic tubes to enable a fuel element to be moved radially in a horizontal plane. Provision is also made for rotating the lower half of the grapple head in order to unscrew control rod guide tubes and to assist the withdrawal of fuel elements which have bowed. The grapple head (Fig. 3) has co-axial input shafts for rotating the lower half thereof, and for operating the grapple hooks. A force sensing device 158 provides signals of the compressive force during grapple ebgagement and of the tensile force resulting from the fuel rod weight and any binding forces preventing withdrawal. The grapple hook housing 160 is biased away from its supporting plate 162 by spring 164; upward movement of the body 160 caused by its abutment with adjacent fuel,elements closes a micro switch 168 to signal engagement of the grapple hooks. Limited tilting and transverse movement of the grapple hook housing 160 is provided by its mounting 170. Transverse movement is biassed towards realignment by springs 180, and axially movement by springs 186 acting on a cylindrical extension 188 of the grapple hook housing. The gas cooled reactor (Fig. 1) is mounted in a concrete cavity, and has fuel rod handling and charging facilities arranged above the reactor, whilst the control rods are driven in and out of the core from below the reactor. Actual removal and replacement of control rods and control rod guide tubes is achieved from above the core by the transfer device. Storage racks 28 are provided for used and replacement fuel rods &c. Concentric coolant parts 18, 20 are provided, the inner one being the discharge part.
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