ES337530A1 - Fuel assembly for nuclear reactor - Google Patents

Abstract

A fuel assembly cooled by the ascending circulation of a fluid through an axial conduit 11 has a casing 1 connected at its lower end to a cylindrical base 4 of smaller diameter, an annular recess 10 being formed in the base 4 and surrounded by a sheath 6 attached to the base 4. The sheath 6 is formed with a series of radial apertures receiving mobile studs 8 disposed in a circle around the base 4 and terminating in heads 8a in the recess 10. A conical portion 2 between the casing 1 and the base 4 bears against a fixed support 12 of the reactor. The cooling fluid enters both the recess 10 and the conduit 11 and acts on the heads 8a of the studs 8 forcing then outwardly into an annular groove 14 in the support 12. As the fluid pressure increases, so the studs 8 are more solidly anchored in the groove 14. When the fluid pressure ceases, the locking force is removed and the assembly can be withdrawn by lifting it upwards, whereupon the edge of the groove 14 cams the studs 8 inwardly into the recess 10. Alternatively, the locking members may be balls co-operating with a ring which slides in the recess and is in contact with the fluid for movement in accordance with the fluid pressure. The ring may be formed with a recess receiving the balls in the unlocked position of the assembly and a spring may be mounted between the ring and the closed end of the recess for returning the ring into the unlocked position. The ring may, alternatively, comprise two cylindrical portions, a first portion which is thin and receives the balls and a second portion which has the same thickness as the recess and is in contact with the fluid. In this case the ring drops by its own weight when the fluid pressure falls to a particular value.