GB874222A - Improvements in or relating to chutes, for example, chutes for fueling nuclear reactors - Google Patents

Abstract

874,222. Handling nuclear fuel elements. STRACHAN & HENSHAW Ltd. Nov. 11, 1957 [Nov. 9, 1956], No. 34417/56. Class 39(4). A shoot for loading and unloading the fuel element channels in the graphite reactor core comprises an outer tube 2 insertable through a selected standpipe to serve a group of sixteen channels 8 the lower end of the tube having a thrust bearing member 4 locating in a hole at the group centre. The hole is provided in a charge pan 6 situated above the core and having openings corresponding to the fuel channels. Within the tube 2 and attached thereto at its upper end is an inner tube having an upper portion 16 and lower portion 18, the portion 18 being pivoted at 20 to the tube 2 and movable through a longitudinal opening 14 in the lower end of the tube 2, Fig. 1, from a position in which it lies wholly within the tube, Fig. 4B. The outward movement of the portion 18 to serve a channel 8 at a certain radial distance is effected by a link 24 connected between the portion 18 and the lower end of a longitudinally movable rod 22 situated between the inner and outer tubes. The link 24 is pivoted at 34 to the rod 22 and has rollers 31 guided in longitudinal slots 32 formed in the tube 2 whereby upward movement of the rod causes outward movement of the tube portion 18. This movement of the rod is obtained by a sleeve (Fig. 3, not shown) mounted on the upper end of the shoot about the shoot axis and coupled to the upper end of the rod 22, the coupling being such that rotation of the sleeve causes longitudinal movement of the rod. The entire shoot may also be rotated about its longitudinal axis to bring the portion 18 opposite the particular channel to be served. The means for rotating the shoot as a whole and also for rotating the sleeve are provided in a headbox surrounding the upper tube end, this headbox being described with reference to Figs. 3, 3A (not shown) and being similar to that disclosed in Specification 874,223. In operation a fuel element is lowered through the shoot by a grab from a charge/discharge machine. A modified shoot capable of extending over a greater radius for serving a greater number of channels (Figs 5-13, not shown) has its lower portion for extension through the longitudinal opening in the outer tube composed of two parts pivotally connected together. One of these parts corresponds to the portion 18 of the previous embodiment and the other part forms a continuation of the first part but is maintained in parallel relation with the outer tube by a linkage so that the other part is always vertically disposed above the selected channel. In a modified headbox (Figs. 14-16, not shown) the vertical movement of the rod 22 is obtained by a roller attached to the rod and running in a helical cam groove in a rotatable sleeve surrounding the shoot. Reference has been directed by the Comptroller to Specification 838,292.