Fuelling of nuclear esp. fast breeder reactor - allowing redn. of reactor vessel dia. as loading operation can be effected at any position within core using large and small revolving stoppers and levelling arm

摘要

In a nuclear reactor fuelling process; the reactor vessel (40) top is closed by a lid (41,42,43) comrising a stationary stopper (41),a large revolving stopper (42) eccentrically fitted to the stationary stopper, and a small revolving stopper (43) which is rotatably and eccentrically mounted in the large revolving stopper; an upper core structure (30), which unites a large number of control rod drives (57), is mounted in the small revolving stopper (43); an upper core structure section (31) can be withdrawn from the upper core structure (30) when fuelling is to be carried out; a loading device (50), with a revolving levelling arm (51), is fitted in the withdrawn section (31); and a fuel (59) loading operation can be carried out at any position within the core (58) by rotation of the large and small revolving stoppers (42,43) and rotation of the levelling arm (51). In a modefied process, the withdrawable section (31) is eccentric w.r.t. the centre of the upper core structure (30), the loading device acts directly and fuel loading is carried out at any position by rotation of the revolving stoppers (42,43) and of the upper core structure (30). USE/ADVANTAGE - The process is useful for refuelling of a fast breeder reactor. The design allows the reactor vesel diameter to be reduced.