ES352674A1 - Nuclear reactor fuel charge-discharge installation - Google Patents

Abstract

A heavy water moderated gas-cooled reactor core 12 is refuelled through channels 13 extending through a slab 19 into a space 18 provided in the pressure vessel 10. The refuelling is performed by a handling facility A described in Specification 1,219,795 which may place a number of spent fuel elements end-to-end in a thimble (Fig. 4, not shown) secured by a lock to the upper end of a pit 20. There are a number of pits 20 but only one is shown, and in alignment with each pit is a passage 30 extending through the roof of the pressure vessel to a metal dome 32 enclosing a winch (Fig. 2, not shown). An extension 48 of the pit leads to a lock 54 controlled by valves 60, 61, the thimble being unlocked and then lowered by a grab controlled by the winch into the lock where it is again locked. Whilst the thimble is in the pit 20, extension 48 and lock 54 it is cooled by the reactor coolant gas. For emergency use, the lock is surrounded by a box 58 through which water may be circulated. The thimble, after unlocking and opening of valve 61 is lowered by a tappet 78 into a magazine tube 72, the magazine then being rotated so that tube 72 lies beneath guide tube 71. A grab operated by a winch 82 lifts the fuel elements one-by-one from the thimble and places each element in a tube 84 leading to a storage pool 86. New fuel elements on a carriage 88 are introduced by lowering them by a gantry 90 through a tube 92 into a magazine tube.