General Electric Company

Thomas W White

Robert S Tsukida

Frank Ortega

Edward W Saxon

Balasubramanian S Kowdley

Christopher J Miller

Thomas A Lewis

Thomas R Eckmann

Robert K Lovell

Andrew S Wong

Edward J Pulpan

An uncoupling tool has a two-module design: one module being a driver assembly for developing the uncoupling movement and the other module being a probe assembly for verifying the uncoupled condition. The probe assembly attaches to the threaded end of the piston tube with its probe extending inside the piston tube. The driver assembly attaches to the CRD ring flange. The probe assembly detects the ring magnet in the drive piston using analog position sensors which operate on the principle of the Hall effect and solid state circuitry. A top sensor provides a signal indicating that the control rod is in its 'full out' position; a bottom sensor provides a signal indicating that the control rod is uncoupled; and an intermediate sensor provides a signal indicating that the control rod is in a transition position between the 'full out' and uncoupled positions. The probe incorporates spacers which focus the magnetic flux onto the sensors. To uncouple the control rod, the probe assembly is lifted using a separate driver assembly.

Multistage control rod drive uncoupling tool

A gauge for ensuring that the uncoupling rod of a control rod drive is properly inserted in the center hole of the spud and not in one of the outer lobes, i.e., spud flow holes, which communicate with the center hole. The uncoupling rod is inserted in the spud. Then the gauge is placed on top of the spud with a centering ring protruding into the spud. The uncoupling rod is correctly installed if it is free to slide inside the gauge and the spud. The gauge is also provided with a ring to protect the spud during transfer of the control rod drive.

Uncoupling rod centering gauge

An improved tool for removing the highly contaminated inner filter from a control rod drive during a maintenance operation. The tool may also be used to install the inner filter by pushing the inner filter on and locking the spring clip onto flats of the center lug of the control rod drive stop piston. The tool has a collet with flexible fingers which are inserted inside the inner filter while flexed radially inward. After the collet is inserted, a retractable cam with a conical bearing surface is retracted to a position whereat it urges the collet fingers radially outward to clamp the collet onto the inner filter. The locked filter must be rotated before removal. With the inner filter coupled to the collet, the tool is then pulled out to remove the inner filter from the control rod drive.

Inner filter removal tool

An improved tool for removing a highly contaminated outer filter from a control rod drive during a maintenance operation. The tool slides onto the control rod drive and surrounds the outer filter with a shield. The shield has a window for removing the screws used to mount the outer filter on the control rod drive. The tool has a support for the spud on the inside thereof. A U-shaped handle is slidably inserted into guideways so that it interlocks with circumferential slots in the shield. The arms of the inserted U-handle latch underneath the ring flange of the outer filter, whereby the outer filter is captured by the tool. The filter-mounting screws are then removed by unscrewing through the aligned window in the shield. Thereafter, the outer filter is removed from the CRD when the outer filter removal tool is lifted.

Outer filter removal tool

Growing community of inventors

San Jose, CA, United States of America

Thomas W White