GB1417416A - Handling grab for nuclear fuel elements - Google Patents

Abstract

1417416 Grabs provided with a preorientation device COMMISSARIAT A L'ENERGIE ATOMIQUE 1 Dec 1972 [2 Dec 1971] 55619/72 Heading B8H A handling grab for charging nuclear fuel elements to a nuclear reactor comprises claws 40 (only one of which is shown) which are pivotally mounted on a member 56 for actuation by a cam 44 mounted at the bottom of an axially rotatable rod 42, Fig. 2, the member 56 being rotatable with the rod 42, the rod 42 being axially movable relative to a surrounding sleeve 38 by means of a lever 46 connected with the rod 42 by means of a ball and socket joint 48, 50, the grab further comprising means for preorientating the claws 40 prior to operation thereof. Such means are shown in Fig. 1 and consist of a vertical rod 2 having an electromagnet 4 at its lower end for engagement with a stainless magnetic head 58<SP>1</SP> of the member 50, the rod 2 being mounted on a disc 14 which is rotatable relative to a flange 10 mounted on a plug 6 covering the reactor pressure vessel. In operation of the preorientation device the rod 2 is moved vertically downwards relative to the disc 14 by the engagement of a motor driven gear 32 with a rack 34 formed on the rod 2 such that the electromagnet 4 engages with the member 58<SP>1</SP> and the rod 2 is then rotated about its longitudinal axis by means of a gear 26, driven by a motor 28, which engages with peripheral teeth 24 on the disc 14, the rod 42 and member 50 and thus the claws 40 simultaneously rotating with the rod 2 through the required angle, after which the electromagnet 4 is deenergized and the rod 2 is raised away from the rod 42. The rod 2 is connected to the disc 14 by means of a metal bellows 23. Instead of the connection between the rods 2 and 42 being provided by electromagnetic means, vertically oriented grooves (78, 80) which intermesh may be provided in said rods respectively, Fig. 3 (not shown).