Abstract: In an installation for handling assemblies between the main vessel of a fast neutron nuclear reactor and an adjoining vessel, use is made of a transfer hood formed by a thick tube whose inclined axis can be moved alternatively into the prolongation of the axes of two inclined ramps opening into the main vessel and adjoining vessel respectively, by the rotation of a platform of vertical axis bearing the hood and also two flaps which close the ramps when the reactor is operating, so that an assembly-transferring pot can be guided isostatically inside the ramps and the hood, the platform also possibly comprising a spare flap.Application to all assemblies forming a reactor core, such as fuel assemblies, lateral neutron screening assemblies and absorbing assemblies.

Abstract: The invention relates to an apparatus for handling nuclear fuel assemblies, as well as to an assembly for use with such an apparatus.The apparatus comprises a vertically axed guide tube in which is displaced a grapnel, suspended on a flexible connection such as a chain, under the action of a reduction gear. As the grapnel is immobilized in rotation in the guide tube, an assembly is gripped by means of a bayonet system by controlling the rotation of the guide tube-grapnel assembly by a reduction gear. The apparatus can in particular be suspended on the small and/or large rotary plug of a fast neutron nuclear reactor. It can also be used in a handling hod under gas.

Abstract: Safety apparatus for a nuclear reactor comprising an absorbing element having a supporting head connected by a disconnectable linkage constituted by the armature of an electromagnet to the end of an axially movable vertical operating rod, said linkage being such that in the case of a disconnection the absorbing element slides by gravity in a passage bounded by an open container through the core of the reactor, wherein the operating rod is associated with a metal member having an expansion coefficient which is significantly higher than that of the armature of the electromagnet, whereby in the case of a temperature rise a separating force is exerted between the head of the absorbing element and the operating rod.

Abstract: Weighing of each control rod and at least the moving portion of the control rod drive mechanism is carried out in continuous operation by means of an assembly comprising at least one strain gage mounted in a circuit for measuring the electrical resistance of the gage according to the change in length which is a function of the weight being measured.