Patent ID: 11935663
Assignee: SMR INVENTEC, LLC
Field: Engines, pumps, turbines (Mechanical engineering)
Classification: CPC G  Y | IPC G

Claim 6:
7. A control rod drive system for a nuclear reactor vessel, the system comprising:
a vertically oriented drive rod mechanically coupled to a control rod drive mechanism operable to raise and lower the drive rod through a plurality of axial positions;
a rod cluster control assembly comprising a plurality of control rods configured for removable insertion into a nuclear fuel core;
a drive rod extension extending axially between the rod cluster control assembly and the drive rod, the drive rod extension having a bottom end releasably coupled to the rod cluster control assembly;
a drive rod extension grapple assembly connected to the drive rod,
the grapple assembly releasably coupled to a top end of the drive rod extension;
the grapple assembly including:
a body defining a downwardly open chamber configured to movably receive the top end of the drive rod extension therein,
the body including a plurality of spring-biased radially retractable lifting pins engageable with the drive rod extension and slideably movable in a linear manner between
a radial inward position projected into the chamber,
and a radial outward position retracted from the chamber,

the drive rod extension including:
a longitudinally-extending actuating tube and an actuating shaft slideably disposed in the actuating tube,
the actuating shaft operably coupled to the grapple assembly for upward and downward movement with the drive rod relative to the actuating;

a lifting head coupled to a first end of a lifting head sleeve tube,
a second end of the lifting head sleeve coupled to the actuator tube;

a diametrically enlarged bobbin slideably disposed and axially movable on the lifting head sleeve,
the bobbin operable to selectively engage the lifting head and enter the downwardly open chamber of the grapple assembly;

wherein the lifting head is configured to engage and force the lifting pins to the outward position when the lifting head enters the chamber of the grapple assembly;
wherein the bobbin is movable in an upwards direction with the lifting head sleeve to engage and retract the lifting pins of the grapple assembly independently of the lifting head;
wherein raising and lowering the drive rod raises and lowers the rod cluster control assembly.