Terminal elements for coupling connecting rods and control rods in control rod assemblies for a nuclear reactor

An apparatus comprising:

• a nuclear reactor pressure vessel;
• and
• a control rod assembly including at least one movable control rod comprising a neutron absorbing material, a control rod drive mechanism (CRDM) for controlling movement of the at least one control rod, and a coupling operatively connecting the at least one control rod and the CRDM, the coupling including a connecting rod engaged with the CRDM and a terminal element connected with a lower end of the connecting rod, the terminal element including a first portion comprising a first material having a first density and a second portion comprising a second material having a second density that is greater than the first density, the terminal element further connecting with the at least one control rod, wherein the connecting rod is detachably engaged with the CRDM such that detachment of the detachable engagement causes a translating assembly including at least the connecting rod, the terminal element, and the at least one control rod to fall toward a reactor core disposed in a lower region of the nuclear reactor pressure vessel, and wherein the first portion of the terminal element supports or contains the second portion of the terminal element.

An apparatus comprising:

• a nuclear reactor pressure vessel;
• and
• a control rod assembly including at least one movable control rod comprising a neutron absorbing material, a control rod drive mechanism (CRDM) for controlling movement of the at least one control rod, and a coupling operatively connecting the at least one control rod and the CRDM, the coupling including a connecting rod engaged with the CRDM and a terminal element connected with a lower end of the connecting rod, the terminal element including a first portion comprising a first material having a first density and a second portion comprising a second material having a second density that is greater than the first density, the terminal element further connecting with the at least one control rod, wherein the first portion of the terminal element comprises a steel enclosure enclosing the second portion of the terminal element.