General Electric Company

Brian H Burrows

Michael Y Suekawa

Neal J Goldberg

Michael A Flanigan

Methods and apparatus for enabling repeatable positioning of inspection and other service tools on an inner diameter of a shroud wall between a top guide and core plate in a boiling water nuclear reactor are described. In one embodiment, the delivery system includes a positioning unit configured to attach to a shroud head flange, a strong back assembly, and a rail assembly connected to the strong back assembly. The positioning unit includes a horizontal member having a plurality of slots and circular shaped openings to mate with seismic pins on the shroud head flange, a radial member and a z-axis adjustment assembly. The radial member extends from the horizontal member to the z-axis adjustment assembly. The z-axis adjustment assembly includes a mast coupling and an elongate screw threadedly attached to the coupling so that as the screw rotates, the coupling moves relative to the radial member. The strong back assembly includes a mast and an extension unit. The mast attaches to the coupling of the positioning unit, and the extension unit is connected to one end of the mast. The mast transfers the load between the extension unit and the positioning unit, thereby causing the shroud to support the weight of the tools. The rail assembly is connected to the extension unit, and the rail assembly includes a rail and a mounting plate movably secured to the rail. The rail assembly further includes a motor coupled to the mounting plate for moving the mounting plate relative to, and along, rail. The rail assembly also includes a plurality of suction cups for removable attachment to an inner wall of the shroud.

Apparatus for performing work in a nuclear reactor

An actuator for performing work in a nuclear reactor is described. In one embodiment, the actuator includes an x-axis linear slide assembly, a y-axis linear slide assembly, and a z-axis linear slide assembly. The x-axis linear slide assembly is mounted to a junction box, the y-axis linear slide assembly is mounted on a carriage of the x-axis assembly, and the z-axis linear slide assembly is mounted on a carriage of the y-axis assembly. The actuator also includes motor assemblies coupled to respective linear slide assemblies. Each motor assembly includes a motor and a resolver sealed in a leakproof can. Pulley-timing belt assemblies couple each motor to a respective lead screw. Specifically, a drive pulley is connected to a rotor shaft of each motor, and a lead screw pulley is secured to an end of each lead screw. Each pulley-timing belt assembly also includes an idler pulley, and a belt extends around the lead screw pulley, the idler pulley, and the drive pulley. The motor assemblies are mounted so that the axis of each motor is substantially parallel to the axis the respective lead screw. By mounting motor assemblies in this configuration, the overall dimensions of the actuator are believed to be minimized when each slide assembly is fully retracted. The actuator further includes a delivery system interface for firmly attaching the actuator to a delivery system, and a tool mounting platform attached to the z-axis linear slide assembly. Threaded openings are located on the platform face and are used to secure various attachments to the platform. Many different attachments, such as an ultrasonic inspection unit, a brushing unit, and an electrical discharge machine (EDM) unit, can be secured to the platform.

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Campbell, CA, United States of America

Brian H Burrows