Westinghouse Electric Corporation

David A Howell

Leonard R Golick

Charles H Roth, Jr

Jeffrey E Hydeman

Joseph J Hahn

Richard J Bodnar

Jeffrey L Slater

Robert S Sekera

Arthur W Kramer

Thomas H Dent

John D Nee

Louis J Tylman

Richard A Green

Bruce S Spofford

Lorraine Fucich

A refueling system for a nuclear power plant utilizing a data network to provide for automatic control and enhanced monitoring of the entire fuel transfer process. The refueling system of this invention provides integrated control of the refueling machine within the containment building, the spent fuel handling machine within the fuel storage building, and the fuel transfer system between the buildings. The system provides supervisory control of the overall system operation via a remote control station, while at the same time, having the capability for local on-line control of each element of the system in the event of network failure. The system may automatically identify individual fuel assemblies with an optical scanner. An in-mast sipper connected to the network automatically tests for leaking fuel assemblies. A revised core load pattern and a revised sequence plan can be calculated by the system in the event of the discovery of a leaking fuel assembly. The system may also include a fuel loading guide to facilitate the automatic loading of bowed fuel assemblies. Human interface with the system may be provided at a plurality of locations, including for example, a refueling control station and a remote status panel. The reactivity of the reactor core may be monitored by the system during core loading, and corrective action taken automatically if a predetermined setpoint is exceeded. Core spacing verification may also be performed automatically.

System for automatic refueling of a nuclear reactor

Process and apparatus are disclosed for removing and replacing the hold down beams of fluid circulating jet pumps mounted in a nuclear reactor. The disclosed process and apparatus are operable from a position such as the refueling bridge remote from the reactor and while the refueling cavity surrounding the reactor is flooded with moderator fluid.

Process for servicing a jet pump hold down beam in a nuclear reactor

Apparatus for servicing a jet pump hold down beam in a nuclear reactor

A replacement station includes an old split-pin-assembly (OSPA) removal stand and a new split-pin-assembly (NSPA) installation stand. The removal stand includes a saw and a drill. With the guide tube to which the OSPA is secured in the removal stand, the saw severs each OSPA below the flange which engages the base of the lower counterbore in the lower guide tube (LGT) separating the OSPA into a pin fragment and a second fragment including the flange and the remainder of the split-pin with the nut threaded into it. The second fragment remains secured to the LGT after the sawing operation. The guide tube is rotated so that the drill is coaxial with the shank of the pin of the second fragment. The second fragment is separated into a third fragment including the flange and a fourth fragment including the remainder of the pin and the nut both removable from the LGT. The installation stand has NSPA blades in which the new split pins are mounted. The LGT sans the OSPA's is positioned on the installation stand. The new nuts are mounted and torqued into the split pins with a long-handled runner and a torque tool permitting a measured torque to be applied to the new nut. Then the cups on the nuts are crimped by a long-handled crimping assembly which has fixed crimping jaws that produce the crimping by moving parallel to the wall of the cup.

Manual replacement of old split-pin assemblies by new split-pin

The guide tube is mounted on a fixture with the split-pins of each old split-pin assembly straddling a knife edge. The nut of each old split-pin assembly is engaged by a socket of a wrench and a high torque is impressed on the nut. The torque is of sufficient magnitude to shear the weld by which the nut is joined to the split-pin and/or to shear the pin particularly at the edge of a keyway where a button to which the weld is joined is engaged. The knife edge which each split-pin straddles prevents the pin from turning under the torque applied to the nut. After the weld or the pin is sheared the nut or the nut and the pin fragment joined to it is unthreaded from the pin or pin fragment and the separated parts are disposed of. Typically the nut of an old split-pin assembly has diametrically cut slots in its wall. The socket of the wrench is provided with projections which engage the nut in the slots. The torque is applied to the nut through these projections.

Removal of old split-pin assemblies from guide tubes and replacement by

The old split-pin assemblies of the lower guide tube of a nuclear reactor are replaced by new split-pin assemblies in a robotic work station under a pool of water. The work station includes a plurality of robotic tools which are remotely actuable from a robotic command center outside of the pool to position the guide tube precisely for a replacement operation, to fragment the old split-pin assemblies and dispose of the fragments under water, and to install a new split-pin assembly. The lower-guide-tube positioning means has a hydraulic cylinder, also remotely actuable externally to the pool, for rotating the guide tube so that it may be oriented properly to be processed by different tools in succession and also so that both split-pin assemblies in each guide tube may be replaced by the same set of tools.

Replacement of split-pin assemblies in guide tubes

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Plum Boro, PA, United States of America

David A Howell