Abstract An illustrative embodiment of the invention provides a fuel element assembly technique that facilitates the insertion of a fuel rod into a cell which is formed by a resilient grid structure. Initially, a cam is introduced into the cell. The inserted cam is rotated to deflect the grid surfaces that comprise the cell walls. This deflection prevents a leaf-spring mounted detent formed in the grid surface from extending into the path of the fuel rod. A key with a dimension that generally matches the deflected grid is inserted into the cell in order to engage the temporarily bowed grid surface. The inserted cam is rotated back to the initial orientation relative to the cell configuration and is withdrawn from the grid structure. The deflecting key lodged against the bowed grid surface, however, sustains the deflection in order to enable the fuel rod to be inserted into the cell without being abraded by the detent. After fuel rod insertion, the matching dimension portion of the deflecting key is disengaged from the grid surface and the key is withdrawn from the cell to release the leaf spring and allow the detent to clutch the fuel rod.
A method for inserting fuel rods into individual cells formed in a fuel element grid that has detents that protrude in toward the center of the cell comprising the steps of inserting a cam into the cell in one direction, rotating the cam in a plane that is generally transverse to said insertion direction, engaging a surface of the cam against the at least one detent, deflecting said detent in a direction that is away from the center of the cell, inserting a key into the cell, engaging a surface of said key to sustain said deflection, withdrawing the cam from the cell, inserting a fuel rod in the cell, and disengaging the key from the cell to relieve said deflection and enable the detents to clutch the fuel rod lodged in the cell.
Claim 2
Independent Claim
134 words
A method for inserting fuel rods into individual cells formed in a fuel element grid that has detents that protrude in toward the center of the cell comprising the steps of inserting a cam into the cell in one direction, rotating the cam in a plane that is generally transverse to said insertion direction, engaging a surface of the cam against the at least one detent, deflecting said detent in a direction that is away from the center of the cell, inserting a key into the cell, engaging a surface of said key to sustain said deflection, withdrawing the cam from the cell, inserting a fuel rod in the cell, and disengaging the key from the cell to relieve said deflection and enable the detents to clutch the fuel rod lodged in the cell.