Absorbing element for a fast neutrons nuclear reactor

摘要

1. Absorber element comprising a casing (10a), intended to be placed vertically in the core (1) of a fast neutron nuclear reactor, and a movable assembly (10b) capable of being displaced vertically inside the said casing (10a) between a high position and a low position, the said movable assembly (10b) having a body (123) made of a neutron-absorbing material and connected by means of a rod (120) to a gripping head (112) capable of being suspended from an electromagnet (19), the said gripping head (112) comprising : - an upper part (114) exhibiting an upper face (114a) capable of coming into contact with the electromagnet (19) and a lower face having a centring collar (132) ; and - a lower part (116), characterized in that the said lower part exhibits an upper face having a centring seat (134), on which the said centring collar (132) of the upper part (114) comes to rest as a result of gravity when the movable assembly (10b) is not suspended from the electromagnet (19) ; the said gripping head additionally comprising - an intermediate part (118) suspended from the said upper part (114) by means of a deformable member of given length (128, 130, 142), this intermediate part having a horizontal upper surface on which a horizontal shoulder (144), oriented downwards and formed on the said lower part (116), comes to rest when the movable assembly (10b) is suspended from the electromagnet (19), the length of the said deformable member (128, 130, 142) being such that the said horizontal upper surface is separated from the said shoulder (144) when the centring collar (132) is resting on the said centring seat (134).