GB882633A - Improvements relating to devices for supporting fuel elements in a nuclear reactor - Google Patents

Abstract

882,633. Reactors; handling nuclear fuel elements. ENGLISH ELECTRIC CO. Ltd. Oct. 3 1958 [July 5, 1957], No. 21306/57. Class 39(4) A sleeve 10 for removably supporting a fuel element 14 in a channel 17 in a reactor moderator structure has four circumferentiallyspeced latches 11 gravity-biased to the vertical position but movable by rams (Figs. 3, 5) to the position shown to rest on the lower face of a groove 15 formed in a support tube 16. The loading ram 33, Fig. 3, comprises a head 30 on which is slidably mounted an annular sleeve 31 biased by a spring 32. On loading a fuel element the sleeve 10 rests in seating 35 and the sleeve 31 holds the latches 11- horizontal, the latches being deflected against the bias of spring 32 as they ride up the tapered surface 16a of the tube 16. On arrival at the groove 15 the spring moves the latches horizontal whereupon the ram 33 may be withdrawn. An unloading ram 41, Fig. 4, comprises a head 40 having a seating 43 which is moved up into the channel to engage the sleeve 10 and lift it to permit the latches 11 to drop to the vertical position whereupon the ram and sleeve may be withdrawn. A combined loading and unloading ram 50, Fig. 5, comprises an upper member 51 rigidly supporting a central bush 53 having a seating 54 to receive the sleeve 10. A cup member 55 is slidably mounted on the bush 53 and is biased upwardly to the position shown by springs 56 acting against the heads of bolts 58 attached to the member 55, the latter then holding the latches 11 horizontal. A sleeve 62 having three angularly-spaced lugs 64 engaging the bottom of the member 55 is slidably mounted in the bush 53 and may be moved downwards against the bias of a spring 63 by a piston 60 when compressed gas is supplied through a duct 81 to the upper end of a cylinder 59. The upper member 51 is slidably connected to a lower ram member 52 by a piston 74 rigid with the member 51 and having its motion restricted, by a flanged ring 76 rigid with the member 52. In a loading operation the gas is supplied at such pressure to the cylinder bore 75 that the member 51 is moved away from the member 52 to permit a normally-open micro switch 82 to close and give an indication, which indication would be cancelled if the fuel element should meet an obstruction. This gas pressure is insufficient to move down the piston 60 whereby when the latches 11 arrive at the groove 15 they are moved outwardly by the springs 56. To unload a fuel element a higher gas pressure is used so that the cup member 55 is moved downwards whereupon when the sleeve 10 is lifted by the seating 54 the latches 11 drop down. If the sleeve 10 should not follow the ram it may be positively removed by increasing the gas pressure still further so that piston 60 moves further down to take up a lost-motion connection between slots 71 in the lugs 64 and pins 70 of links 69. The links 69 are connected to levers 66 pivoted on the bush 53 and is biased by springs 72 to the position shown, the levers being moved by the high gas pressure to engage an annular groove 10a in the sleeve.