Removal and replacement of fuel rods in nuclear fuel assembly

Patent · Tue Jun 11 04:00:00 EDT 1985

OSTI ID:5947033

Shallenberger, J M; Ferlan, S J

To remove the bottom nozzle of a nuclear fuel assembly, the nozzle plate must be disconnected from the control-rod thimbles. For nozzles whose control-rod thimbles are connected to the nozzle plate by screw fasteners having lock pins welded to the nozzle plate, a cutter for severing the welds is provided. The cutter is rotated by a motor at the work position through a long floating shaft. A long feed shaft operated by a thumb nut at the work position feeds the floating shaft and cutter downwardly through the weld. The bushings extend from a bushing plate, each encircling a screw fastener. Each bushing has a yieldable sleeve for sealing the region around a screw fastener to trap the chips from the severed weld. The cutter is indexed from weld to weld by indexing plates. To remove chips adhering to the cutter, the suction tube of a suction-pump-operated eductor is inserted in the auxiliary hole and the cutter is inserted in the bushing and chips are removed by suction. By inserting the suction tube into the bushings which seal the regions around the screw fasteners and enabling the eductor, the captured chips may be removed. Once the welds are severed the screw-fasteners may be unscrewed and removed by the eductor. The bottom nozzle may then be removed.

• Assignee: Westinghouse Electric Corp.
• Patent Number(s): US 4522780
• OSTI ID: 5947033
• Country of Publication: United States
• Language: English

Related Subjects

22 GENERAL STUDIES OF NUCLEAR REACTORS
220200* -- Nuclear Reactor Technology-- Components & Accessories
BUSHINGS
CUTTING TOOLS
EQUIPMENT
FABRICATION
FASTENERS
FUEL ASSEMBLIES
FUEL ELEMENTS
FUEL RODS
JOINING
JOINTS
MATERIALS HANDLING EQUIPMENT
NOZZLES
PLATES
REACTOR COMPONENTS
REMOVAL
RETROFITTING
TOOLS
WELDED JOINTS
WELDING