Supporting grid for nuclear reactor fuel elements - has elements in peripheral cells gripped between inner bosses and outer springs

A supporting grid for spacing the fuel elements of a fuel element cluster in a water-cooled nuclear reactor defines a block of square-section cells each accommodating one fuel element and is made up of interlocking flat strips welded together and made of Zr alloy. A spring member (37) of Ni alloy is secured between each peripheral strip (36) and the ends of the strips (32, 33) which run perpendicular thereto. Member (37) resembles a ladder, presenting a rung-like spring section (44) inwards of each of the cells in the peripheral row adjacent strip (36). The strip (31) defining the wall of each of those cells opposite strip (36) carries rigid bosses (47) pressed out of the strip. The elements in those cells are gripped between bosses (47) and spring sections (44). The peripheral strips (36) and/or the spring members (37) may be made separately on each side of the grid or may bend round one or more of the corners. ADVANTAGE - The free space between fuel elements in the peripheral cells of a cluster and the peripheral strips defining the outer walls of those cells is reduced, which reduces the risk of guide fins on one cluster becoming interlocked with those of another cluster when the other cluster is being moved axially into the reactor past clusters already in place. Des ressorts (44) sont rapportés contre la face interne de chacune des plaquettes extérieures (36) de la grille-entretoise. Les ressorts (44) sont saillants à l'intérieur d'une partie au moins des cellules périphériques (35) de la grille-entretoise. Chacune des plaquettes internes (31) parallèle à une plaquette extérieure (36) et délimitant une cellule périphérique (35) vers l'intérieur porte des bossettes rigides (47) en vis-à-vis de chacun des ressorts (44) de la plaquette extérieure (36). On limite ainsi les risques d'accrochage des grilles-entretoises lors de la manipulation des assemblages combustibles.