Method for refuelling a nuclear reactor

摘要

An upper core structure called the UCS is divided into a plurality of structural elements (31) in a longitudinal direction, and a rotational function is given to the divided structural elements (31) of the UCS so that they can turn in a single piece and form a rotary UCS plug (33). This rotary UCS plug is rotationally mounted on a fixed plug (51) arranged at the top of a reactor vessel (50). In order to refuel the reactor, at least one of the divided structural elements (31) of the UCS is pulled out of the rotary UCS plug (33), and a refuelling machine (40) provided with an offset rotary arm (41) is fitted into the part thus freed. A fuel element (55) at an arbitrary position in the core can be replaced by rotating the rotary UCS plug (33) and rotating the offset arm (41) of the refuelling machine (40). <IMAGE>