Patent GB-1399768-A (GB)
Title: Nuclear fuel pellet loading machine
IPC: G21C21/08
Filed: 1973-05-29
Abstract: 1399768 Nuclear fuel pellet loading machine WESTINGHOUSE ELECTRIC CORP 29 May 1973 [13 June 1972] 25475/73 Heading B8C A machine 10 for loading fuel pellets 38 into nuclear fuel rods 12 comprises a base supporting rack 16 arranged to hold a multiplicity of fuel rods 12, a table 18 disposed adjacent, and in alignment with, said rack on the base for holding multiple columns of fuel pellets 38 respectively corresponding to the number of fuel rods, a transition plate 48 disposed between the rack 16 and the table 18 and having channels formed therein in alignment with the fuel rods on the rack 16 and the columns of fuel pellets on the table 18, and a power driven device 68 associated with said base and having members 70 arranged to contact said columns of fuel pellets to feed the pellets into the fuel rods. As shown, the fuel rod support rack 16, pellet table 18, and pellet sensing table 14 are supported on a base 20 and a stand 22 which allows adjustment of the machine at an angle of approximately 8 degrees to the horizontal. The fuel rod rack 16 includes a base 24 and several spaced vibrators 26 which are secured to the brackets 25 and which carry an upper plate 28 which contains a multiplicity of semicircular grooves 30 to receive the fuel rods 12 which can be held in position by clamps 32, 32 preferably provided with complementary grooves. The plate 28 may be adjusted vertically on the base 24. The pellet table 18, which is vertically adjustable on a framework 40, supports a removable tray 36, which has a number of parallel bars 37, Fig. 3, spaced a distance less than pellet diameter to ensure exact alignment of the pellet columns. The transition plate 48, adjustably mounted on bars 50 secured to a base 20, is provided with a number of semicircular grooves 52 having a diameter slightly larger than that of a pellet and a ledge 54 which serves as a stop for the upper ends of the fuel rods. Each of the latter is provided with an anticontamination funnel 60 and a lead-in funnel 66. The mechanism for pushing the elements 38 into the fuel rods 12 comprises a plurality of fingers 70 carried by holders 82 slidably mounted in a block 68 which is slidably mounted on a pair of spaced bars 72 and is movable, in a direction in line with the columns of fuel pellets, by means of a screw 76 which is driven by a variable speed motor and gear-box unit 74. A micro-switch 78, mounted on a drive screw 80, reverses the motor unit 74 when the block 68 reaches the end of its advancing travel. Each finger 70 is loaded by a spring 92 which limits the amount of force that the finger can apply to the pellets, and is associated with a microswitch 94, having a trip arm 98. The holders 82 are held in their normal position, flush with the sides of the block 68, by an adjustable ball catch 104, 110. A sensing mechanism 116, to determine when a fuel rod is loaded with the correct number of fuel pellets, comprises a block 118 with bores 122 which each receive a tube 126 and a pin 124 therein which is biased outwardly towards the aligned fuel rod by a spring 128, a corresponding number of microswitches 130 being mounted on a bracket 132 attached to the block 118. Controls 112, 114 respectively regulate the motor 74 and the vibrators 26.