Abstract: A pedestal plug is sized to fit into a cladding of a nuclear fuel rod. A lower end plug is sized and shaped to plug the lower end of the nuclear fuel rod. One of the pedestal plug and the lower end plug includes a protrusion and the other of the pedestal plug and the lower end plug includes a hollow region into which the protrusion fits. In one embodiment the pedestal plug is a hollow cylindrical pedestal plug and the protrusion is disposed on the lower end plug. The protrusion disposed on the lower end plug suitably press fits into the hollow cylindrical pedestal plug. In a method of assembling a fuel rod of a nuclear reactor, the pedestal plug and the lower end plug are press fit together, and after the press fitting the lower end plug is welded to a cladding of the fuel rod with the pedestal plug disposed inside the cladding.

Abstract: A tool for use with an integral reusable locking arrangement between the guide tubes and upper end fitting in a nuclear fuel assembly. A positioner on the tool locates the tool on the upper end fitting grillage and aligns a wrench on the tool with projections on a spring collar used in the locking arrangement. The wrench on the lower end of the tool has slots that engage with the reusable locking arrangement on the guide tube upon application of downward pressure on the tool driver. Rotation of the driver causes corresponding rotation of the spring collar on the reusable locking arrangement for locking or unlocking of the upper end fitting in place relative to the guide tubes. Axial and rotational motion of the driver is limited by interaction between a set screw on the positioner and slots in the driver. Upward motion of the driver disengages the wrench from the spring collar for removal of the tool.