Fuel rod guiding apparatus and method therefor

Abstract

A guiding apparatus and a method are presented for efficiently guiding and loading fuel rods into a fuel assembly without introducing surface damage to the fuel rod. The apparatus simultaneously loads a row of fuel rods into the grid cells of the grids using the guiding device, disposed at the entry side of each grid. The guiding device includes a comb-shaped section and a freely detachably engaged bottom side wall plate, forming a plurality of guiding spaces to superimpose on the plurality of grid cells requiring fuel rods. The guiding device is provided with protective guiding strips which are inserted into the grid cells prior to inserting the fuel rods so as to protect the fuel rod surface from being scratched by the springs and dimples provided. The method of fuel rod insertion using the apparatus is as follows. The guiding spaces formed by the comb-shaped section and the bottom side wall plate are placed adjacent to the opening end surface of a row of grid cells. After the fuel rods are inserted, the comb-shaped section is separated from the bottom side wall plate, and is raised to the next row of horizontal grid cells. The detached bottom side wall plate located below the fuel rods is rotated away and then raised above the fuel rods to the next row of horizontal grid cells. The bottom side wall plate is now rotated back and reengaged with the comb-shaped section and the loading process is repeated for the row above.