Patent GB-953298-A (GB)
Title: Nuclear reactor fuelling arrangement
Inventor: LEMESLE GEORGES
IPC: G21C19/18
Filed: 1963-02-13
Abstract: 953,298. Fuelling and servicing reactors. COMMISSARIAT A L'ENERGIE ATOMIQUE. Feb. 13, 1963 [Feb. 20,1962], No. 5872/63. Heading G6C. The core 14 of a gas-cooled reactor is enclosed in a chamber 16 in a concrete pressure vessel 10, an upper chamber 18 above a concrete cap 20 receiving fuelling machines 40 (only one shown) as disclosed in Specification 953, 297. Each machine 40 has a magazine 50, a first grab for picking up and putting down the magazine, and a second grab for transferring fuel elements between the pickedup magazine and vertical channels in the core 14. There are three machines 40 each displaceable along a respective track 36, the three tracks being independently rotatable about an overhead pivot centrally disposed in the chamber 18. Thus each machine 40 may be aligned with a selected core channel. The chamber 18 also serves as a storage space for fresh fuel elements which are to be loaded into the reactor core and for spent fuel elements which are to be removed from the vessel 10. The storage space comprises a circular track 46 surrounding the cap 20 on which ride a train of trucks 48, each truck being capable of receiving a fuel element magazine 50. The magazines 50, loaded with fresh or spent fuel elements, are transferred between the chamber 18 and the outside of the vessel 10 through a selected one of three equiangularly spaced passages 52 extending through the concrete 10 into auxiliary shield sections 58. Each passage 52 (only one shown) includes a conveyer for transporting the loaded magazines, the conveyer including a gantry 54 running on a track 56. The gantry 54, Fig. 10, comprises a grab 138 for picking up and putting a magazine 50, a frustopyramidal nose 144 on the gantry co-operating with a similarly shaped recess 90 in the magazine ensuring that the magazine is maintained in a fixed angular relation relatively to the gantry, in the same way that the magazine is maintained relatively to a fuel handling machine 40 as disclosed in Specification 953,297. Each passage 52 extends to an elevator shaft 60 at atmospheric pressure and since the gas pressure in chamber 18 is maintained above that in chamber 16, the passage has a lock constituted by part-spherical lock doors 62, 64 rotatable about a horizontal axes. In Fig. 2 door 62 is open and door 64 is closed. Tracks in the doors (Figs. 4, 5, not shown) ensure continuity of the track 56 when the doors are open. Cage 126 in the shaft 60 is controlled by a hoist 128 and has a track 131 alignable with the track 56. In a fuelling operation the cage 126 lifts a magazine 50 containing fresh fuel elements, until the track 131 is aligned with track 56 whereupon the gantry 54 is advanced to pick up the magazine and put it down between the two doors 62,64. This is performed a number of times (e.g. three), the door 64 is closed, the door 62 is opened and the three magazines 50 are transported one at a time by the gantry 54 on to a respective truck 48, the truck having been aligned with the end of the passage 52. The fuelling machines 40 pick up the magazines from the trucks, remove spent fuel elements from the channels they are serving into empty compartments of the magazines and deposit the fresh fuel elements from the magazines into the channels. The machines 40 return the magazines filled with spent fuel elements to the trucks and the magazines await in that position for radioactivity to decay and cooling to take place after which they are returned by the gantry 54 to the elevator cage 126. In order to remove a defective machine 40 and replace it by a spare machine a track 45,68 extends along the roof of the passages 52 and the tracks 36 may be aligned with the tracks 45,68. A remote controlled manipulator (Fig. 13, not shown) is supported on a track on the cage 126 and the latter is raised to align this track with the track 68 whereupon the manipulator is advanced to engage the machine 40 and return the latter to the cage 126. The fuelling operations may be monitored by a periscope introduced through a passage 41 and co-operating with a mirror 43 on the machine 40.