Control rod remote holdout mechanism

A holdout mechanism for use with a control rod drive mechanism having a torque tube, comprising:

• a connecting rod including at least one cam extending radially-outwardly from an outer surface of the connecting rod, and an annular collar defining a key slot, the annular collar extending radially-outwardly from the outer surface of the connecting rod;
• an elongated key that is slidably receivable within the key slot, the elongated key being non-rotatably fixed to an inner surface of the torque tube;
• and
• a holdout collar disposed non-rotatably within the torque tube, the holdout collar including an inner surface defining a central bore and at least one locking recess therein, the locking recess extending upwardly from a bottom edge of the holdout collar;
• wherein the connecting rod is axially-movable with respect to the control rod drive mechanism between a first position in which the elongated key is disposed within the key slot so that the connecting rod is non-rotatable with respect to the control rod drive mechanism, and a second position in which the elongated key is removed from the key slot and the connecting rod is rotatable with respect to the control rod drive mechanism,
• wherein when the connecting rod is in the first position the at least one cam is removed from the locking recess, and in the second position the at least one cam is disposed within the locking recess.

A holdout mechanism for use with a control rod drive mechanism having a torque tube, comprising:

• a connecting rod including at least one cam extending radially-outwardly from an outer surface of the connecting rod, the connecting rod being axially-movable with respect to the control rod drive mechanism between a first position in which the connecting rod is non-rotatable with respect to the control rod drive mechanism, and a second position in which the connecting rod is rotatable with respect to the control rod drive mechanism;
• a holdout collar disposed non-rotatably within the torque tube, the holdout collar including an inner surface defining a central bore and at least one locking recess therein, the locking recess extending upwardly from a bottom edge of the holdout collar;
• wherein when the connecting rod is in the first position the at least one cam is removed from the locking recess, and in the second position the at least one cam is disposed within the locking recess;
• and
• a spring positioned above a top end of the connecting rod, the spring urging the connecting rod in a downward direction when the at least one cam is disposed within the locking recess.