DISPOSITIF DE DECLENCHEMENT ET D'INSERTION D'ELEMENTS ABSORBANTS ET/OU MITIGATEURS D'UN REACTEUR NUCLEAIRE METTANT EN ŒUVRE DES ELEMENTS FLEXIBLES ET ASSEMBLAGE DE COMBUSTIBLE NUCLEAIRE COMPORTANT UN TEL DISPOSITIF

The invention provides a triggering and inserting apparatus and a system comprising the same. The system is used for triggering and inserting a neutron absorber and/or mitigant into a fission area of a nuclear reactor and is installed in a nuclear fuel component in which a coolant flows. The system comprises a container (10) having a holding device (11) used for fixing the absorber (2) to a non-inserted position. The holding device comprises at least three flexible members (20) forming a base for an end member (2.0) of a to-be-inserted component (2), wherein the component is arranged among the flexible members (20). When the temperature of the coolant is below a triggering temperature, a locking surface (31) prevents the end member itself from getting away from the holding base; after unlocking, the end member (2.1) is released through the deformation of the flexible members (20). The deformation is caused by force applied by mass of the to-be-inserted component. The invention also relates to a nuclear fuel component, a nuclear reactor and a sodium-cooled fast neutron nuclear reactor.