| 摘要 |
932,438. Servicing reactors. UNITED KINGDOM ATOMIC ENERGY AUTHORITY. Dec. 11, 1961 [Dec. 12, 1960], No. 42638/60. Class 39 (4). A tool for withdrawing an upstanding fuel element support spike 1 situated in the lower region of a reactor core, the spike being a push-fit in a sleeve 3 and abutting a shoulder (not shown) therein, the sleeve 3 being supported by a horizontal plate 4 and upward withdrawal of the spike being normally prevented by three angularly-spaced latches 6 pivoted on the spike and having notches 9 engaging an undercut portion 3b on the sleeve, comprises a casing 11 having at its upper end a headpiece 13 whereby it may be suspended from the graphite of the reactor fuel element charge machine. A shroud 12b extends from the lower end of the casing and within the shroud is a cylindrical piece 12 having a tapered bore 12a complementary to the spike. The piece 12 is integral with a ram rod 33 connected to a piston within a cylinder 34 rigid with the casing. A tube 23 rotationally mounted by bearings 25, 26 between the rod 33 and an outer tube 27 is internally-threaded at 23b to co-operate with the threaded end 24b of an actuating sleeve 24 having splines 24a co-operating with splines on the piece 12 whereby rotation of the tube 23 causes axial movement of the sleeve 24. The tube 23 is rotated by a shaft 19 having at its lower end a gear-wheel 21 meshing with an annular gearwheel 22 on the tube 23, the lower end of the shaft being formed of two telescopic sections 196, 19c having splined engagement with each other. The upper end of the shaft carries a pinion 18 meshing with teeth 16b on a member 16 rotatable on a stud 14, splines 16a on the member 16 enabling it to be rotated by the charge machine grapple. Rollers 28 on the tube 27 permit axial movement of the unit 23 27, 33 in the casing 11. Three pairs of angularly-spaced brackets 28 on the sleeve 24 have cam slots 29 receiving rollers 31 connected to pins 30, the three pins extending through elongated holes 24c in the sleeve and through holes 32 in the piece 12. When the tool is lowered on to the spike 1 the pins 30 are opposite an annular groove 10 in the spike. The grapple is rotated a predetermined number of times so that the sleeve 24 is advanced and the cam slots 29 move the pins 30 into the groove 10; also, the free end of sleeve 24 moves the latches 6 inwardly against the bias of spring tongues 7 so that they disengage the undercut portion 3b. The grapple is rotated one further turn to cause a carriage 20 having a screwthreaded engagement with a shaft portion 19a to advance axially sufficiently to actuate a valve 36 whereby compressed coolant gas is supplied from a reservoir 35 to the cylinder 34 and the rod 33 withdraws the spike 1 into the casing 11.
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