GB1022126A - Machines for removing splitter blades from nuclear reactor fuel cans - Google Patents

Abstract

1,022,126. Removing canning from nuclear fuel. FAIREY ENGINEERING Ltd. Nov. 29, 1963 [Nov. 30, 1962], No. 45532/62. Heading G6R. [Also in Division B3] A machine for stripping splitter blades from a used nuclear reactor fuel can which comprises in combination, support means for the fuel can complete with its splitter blade assembly, cutter mechanism constructed and arranged to sever the strap securing means of the splitter blades to the can, withdrawal mechanism constructed and arranged to grip the splitter blade and withdraw it radially outwards from the can, and control means to actuate first the cutter mechanism and then the withdrawal mechanism. The can 10, Fig. 16 (not shown), has radial fins 14 and four radial splitter blades 11 secured together by five spaced apart sets of four interconnecting straps 12 having lugs 16 which are riveted to the blades. The machine, Fig. 1 (not shown), includes a carriage 20 which is moved along rails 21 by a carriage traverse jack 22. The can is mounted on the carriage between a rotatable tailstock 28 and a rotatable headstock 27 which can be moved longitudinally by an hydraulic jack 31. Two pairs of spring-loaded guide plates position the can, which is delivered from above by a manipulator, with the splitter blades in planes at 45 degrees to the vertical. With the can in position the headstock 27 is moved to clamp the can against the tailstock 28 and then the carriage 20 is moved to the right in Fig. 1 until dogs 40 on the tail-stock shaft engage a locating bar 41 mounted on a crank 42 which can be oscillated 45 degrees on either side of a central position by a jack 44, to bring first one pair of blades and then the other into the horizontal plane. With the can orientated to bring one pair of blades into the horizontal plane the carriage 20 is traversed to the left in stages to bring each set of connecting straps 12 into position between a pair of hydraulic cutter mechanisms supported by an intermediate frame 45. Each cutter mechanism 46, Fig. 2, is suspended from the frame by a parallel motion linkage 48 and the linkages are joined by a jaw positioning jack 70. The cutter mechanisms 46 each comprise a double toggle linkage including two jaw levers 57, two toggle levers 58 and an hydraulic jack which is connected between pivot pins 55 and 56 so that the cutting jaws 62 close when the jack 53 is retracted. The mechanism as a whole is free to pivot about pins 66, the movement being limited by the engagement of the pin 56 in a profiled aperture 67 in the sideplates 52 by which the mechanism is mounted. A microswitch 68 indicates when the jack 53 is fully retracted and microswitches 71 on opposite sides of the frame 45 indicate when the mechanisms 46 are at their position of extreme separation. In operation the traverse of the carriage is stopped when each pair of straps is opposite the cutters, the positioning jack 70 is actuated to bring the mechanisms towards one another on either side of the fuel can so that the straps 12 are between the cutter jaws 62 and the cutter jacks are then actuated to close the jaws and cut through the straps but not through the splitter blades. When the carriage reaches the position to cut the last set of straps a plunger 72 drops into a recess in the track and operates a valve controlling a support jack 74 which raises a blade support member 75 into contact with the splitter blades 11. When all the straps have been severed the carriage is returned to the extreme right-hand position to bring the severed blades between the jaws of a blade withdrawal mechanism which comprises two pairs of arms 80, Fig. 4 (not shown), spaced apart along the track, each pair being connected by a jack 84. Two pairs of spring-loaded jaws 85 are carried by the arms, the springs biasing the jaws to the closed position and a pair of hydraulic jacks 89A being provided to open the jaws against the force of the springs. With the can in position between the arms 80 and the jacks 89A actuated to open the clamping jaws, the jacks 84 are operated to draw each pair of arms 80 together, the jacks 89A are retracted to allow the jaws to close on the splitter blades and the jacks 84 are extended to withdraw the blades radially from the can. When the arms 80 are fully separated the jacks 89A are actuated to open the jaws and the blades 11 fall into a crushing box 91. The crushing box comprises pivoted longitudinal side walls 92 actuated by a pair of crusher jacks 94, a vertically sliding gate 95 at one end, operated by hydraulic jacks 96 and a triangular piston 99 operated by an hydraulic ram 97, which first crushes the splitter blades and then ejects the compacted metal after the gate 95 has been opened.