초록 ▼

A system for removing and installing a control rod drive from a drive housing mounted in the vessel of a boiling water reactor. The system comprises a carriage supported by and movable along the service rails normally present in the undervessel cavity, and a cradle pivotally connected to the carriag

A system for removing and installing a control rod drive from a drive housing mounted in the vessel of a boiling water reactor. The system comprises a carriage supported by and movable along the service rails normally present in the undervessel cavity, and a cradle pivotally connected to the carriage and having a length substantially less than the length of a control rod drive. The pivot point between the cradle and the carriage is chosen such that the length of the carriage is subsumed within the length of the cradle when the cradle is pivoted into a horizontal position. The pivoting movement is accomplished by means of a hydraulic cylinder connected between one end of the carriage, and the upwardly-swinging end of the cradle. The cradle includes a lifting and lowering mechanism formed by the combination of a leadscrew drive and a hydraulic cylinder. The hydraulic cylinder is slidably connected to the cradle so that it is movable between a recess within the cradle when not in use to a position directly beneath and in tandem with the control rod drive when in use. The lifting and lowering mechanism can move a control rod drive from a position coterminous with the bottom end of the carriage to an installed position within a drive housing without the need for installation of special end effectors or other components onto the system.

대표청구항 ▼

A system for removing and installing an elongated control rod drive from a drive housing mounted in the vessel of a boiling water reactor of the type having an undervessel cavity with a pair of service rails one of which includes a tapered surface along its upper edge, comprising: a control rod driv

A system for removing and installing an elongated control rod drive from a drive housing mounted in the vessel of a boiling water reactor of the type having an undervessel cavity with a pair of service rails one of which includes a tapered surface along its upper edge, comprising: a control rod drive installation and removal assembly including a carriage means supported by and movable along service rails and having a length less than that of a control rod drive, and including a plurality of pairs of carriage wheels, at least two pairs of which include wheels having circumferential grooves that are complementary in shape to the tapered surface of said service rail to afford positive traction between said rail and said grooved wheels, and a drive train including a remotely operable and reversible hydraulic motor having a drive shaft that is coupled to both of said grooved wheels through a drive reduction mechanism that reduces each turn of the output shaft of the hydraulic motor to about one-third of a turn for each of the grooved carriage wheels, a cradle means having a length less than the length of a control rod drive but greater than the length of the carriage means and pivotally mounted onto the carriage means and movable between a vertical position and a horizontal position wherein the length of the carriage means is subsumed within the length of the cradle means, wherein said cradle means includes a securing means for detachably mounting a control rod drive to the cradle means, and a lifting and lowering means within the interior of the cradle means and operatively connected to the securing means and adapted for moving a control rod drive between a position where one of its ends is coterminous with one of the ends of the cradle means, and a position where it is installed within said drive housing.