Patent GB-1008506-A (GB)
Title: Fuel element charging arrangements for nuclear reactors
IPC: G21C19/16
Filed: 1962-11-14
Abstract: 1,008,506. Fuelling reactors. SOC. DES FORGES ET ATELIERS DU CREUSOT. Nov. 14, 1962 [Nov. 14, 1961], No. 43058/62. Addition to 940,734. Heading G6C. A shoot enabling fuel elements to be transferred between a charge machine and channels in a reactor core D comprises a casing 10 adapted to be supported by lifting and lowering mechanism 12 and rotatable by gears 20. A tube 26 telescopic within the casing 10 has an external flange 28 engageable with a flange 30 on the casing to limit the telescopic movement and an internal groove 32 for engagement by a grab of a preparation machine. When the shoot is lowered through the standpipe by the preparation machine the tube 26 supports the casing 10 until the latter is arrested by the mechanism 12. A supporting tube 40 of U- shaped cross-section is connected by a universal joint 38 to the lower end of tube 26, the tube 40 carrying a pivot assembly 42 enabling rotation of the shoot about its axis. A tubular arm 44 pivoted at its upper end to the tube 40 is connected by links 50 to a member 54 axially movable within the tube whereby the arm may be moved outwards from within the tube 40 into alignment with conical seats 46 leading to the fuel element channels in the core D. The assembly 42 is supported by the lower end 56 of the tube 40 when the shoot is lowered by the grab and comprises, Fig. 6, a member 58 rigid with the member 54 and with a nut 60. The nut 60 co-operates with a threaded rod 62 rigid with a sleeve 64 and having a centering nose 66. A spring 82 is compressed between thrust washers 84, 86, the washer 84 abutting an internal shoulder on a housing 70 and the washer 86 abutting shoulders on the sleeve 64 and housing 70. A key 78 on the housing 70 co-operates with a longitudinal slot in the sleeve 64. When the shoot is lowered by the grab a flange 72 on the housing is arrested by a surface 68 of the charge pan 48 and a key 76 on the surface 68 engages a keyway 74 on the housing whereby the housing 70, sleeve 64 and rod 62 are locked against rotation, Fig. 6. The weight of the shoot is now taken by the lifting and lowering mechanism 12 which is in its upper position so that flanges 28, 30 engage and the grab may be removed. The gears 20 are operated to simultaneously rotate the shoot about its longitudinal axis and thread the nut 60 upwards relatively to the rod 62 to determine the angle to which the arm 44 will be opened upon subsequent lowering of the shoot, it being understood that for any angular rotation of the shoot about its axis the nut is displaced such an amount that the arm on lowering coincides with a fuel channel in the core D. During this operation the arm 44 remains supported by the tube 40, casing 10 and the mechanism 12; the assembly comprising the rod 62, sleeve 64 and housing 70 (coupled to the sleeve by spring 82) moves downwardly. The shoot is further lowered by the mechanism 12, Fig. 2, the tube 40 and tube 26 being no longer supported by the casing 10 move downwardly and the tube end 56 moves clear of the member 54, Fig. 3, which is retained by the washer 86. The member 54 (to which the links 50 are pivoted) being resiliently held against movement by the abutment of the sleeve 64 against spring 82, the links move the arm 44 to the Fig. 3 position. In order to index the arm 44 on to another channel, the casing 10 is raised by the mechanism 12 thereby removing the load on tube 40. The arm 44 then folds back automatically and the shoot is orientated by the gears 20. The shoot may be used in the pneumatic fuel removal system described in Specification 961,388.