General Electric Company

Thomas A Lewis

Frank Ortega

Balasubramanian S Kowdley

Robert S Tsukida

Edward W Saxon

Jeffrey L Thompson

Thomas W White

Christopher J Miller

Thomas R Eckmann

Paul Debenedetto

Andrew S Wong

Methods and apparatus for maintaining a compression force in a reactor pressure vessel (RPV) of a nuclear reactor are described. In one embodiment of the apparatus, a spring assembly facilitates applying compression force on the shroud head. The spring assembly, in one embodiment, includes two trusses and two torsion bars. The torsion bars extend between the trusses and are connected at opposite ends to the trusses. Each truss includes a truss support member, a hooking element, and a torsion converter element. The truss support member is configured to rest on the shroud head flange. The hooking element is pivotally coupled to the truss support member, and includes a hook adjacent a guide rod. The torsion converter element is coupled to the hooking element, and is vertically movable with respect to the truss support member. The converter element has two ends, each end splined to one of the torsion bars so that vertical movement of the converter element drives, e.g., rotates, the torsion bars.

Methods and apparatus for applying a compressive force to a core shroud

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 method and a gage for testing uncoupling tools to ensure proper operation prior to use. The uncoupling tool gage simulates the actual conditions under which the uncoupling tool is expected to perform. The gage has a cylindrical guide for slidably receiving a magnet housing. The guide is supported such that it is concentric with respect to the probe of an uncoupling tool to be checked. The magnet housing is placed inside the cylindrical guide and then moved toward the bottom thereof. When the magnet moves into proximity with a switch in the uncoupling tool probe, an indicator lamp in the uncoupling tool illuminates. If the face of the magnet housing is within a range band on the outside of the guide when the indicator is illuminated, then the uncoupling tool is operating properly.

Control rod drive uncoupling tool gage

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San Jose, CA, United States of America

Thomas A Lewis