METHOD OF INSERTING A REPLACEMENT FUEL PENCIL IN A FUEL ASSEMBLY FOR A NUCLEAR REACTOR AND GUIDING DEVICE

摘要

Before inserting a replacement fuel pin (2') through the intermediate grid (3) of the fuel assembly, two rigid guidance plates (8, 8') with a series of notches (11) along their edges are introduced laterally into the spaces between a row of fuel pins, from the side of the grid. The plates (8, 8') are then rotated 45 degrees about their longitudinal axis so as to engage the notches round the existing pins in the row. This creates an axial extension of the empty cell (7') to provide guidance as the replacement pin (2') is inserted. This procedure is repeated for all the grids in the fuel assembly.