METHOD FOR DESIGNING A FUEL ASSEMBLY OPTIMISED AS A FUNCTION FO THE CONDITIONS OF USE IN LIGHT WATER NUCLEAR REACTORS AND RESULTING FUEL ASSEMBLY

The invention relates to a method for design of a fuel assembly for nuclear reactors, comprising structural components made from zirconium alloy: the mean uniaxial tensile or compressive stress to which said components are subjected during the assembly life is calculated, the zirconium alloy of which the components are made is selected according to the following criteria: those components subjected to an axial or transverse compressive stress of between -10 et -20 MPa are made from an alloy with a content of Sn between Sn = (-0.025s - 0.25) % and Sn = -0.05s % : those components subjected to such a stress of between 0 et -10 MPa are made from an alloy the Sn content of which is between Sn = traces and Sn = (0.05s + 1) %: those components subjected to such a stress of between 0 and +10MPa are made from an alloy the Sn content of which is between Sn = 0.05s % and Sn = (0.07s + 1) %:and those components subjected to such a stress of between +10 and +20MPa are made from an alloy the content of SN of which is between 0.50 % and 1.70%. Fuel assembly made according to said method. Procédé de conception d'un assemblage de combustible pour réacteur nucléaire comportant des composants de structure en alliage de zirconium : - on calcule les contraintes uniaxiales moyennes de traction ou de compression auxquelles seront soumis lesdits composants pendant la vie de l'assemblage; - et on choisit les alliages de zirconium dans lesquels lesdits composants seront réalisés selon le critère suivant : * ceux soumis ô une contrainte de compression axiale ou travers comprise entre -10 et -20MPa seront réalisés en un alliage dont la teneur en Sn est comprise entre Sn = (-0,025s - 0,25) % et Sn = -0,05s % * ceux soumis ô une telle contrainte comprise entre 0 et -10MPa seront réalisés en un alliage dont la teneur en Sn est comprise entre Sn = traces et Sn = (0,05s + 1) % * ceux soumis ô une telle contrainte comprise entre 0 et +10MPa seront réalisés en un alliage dont la teneur en Sn est comprise entre Sn = 0,05s % et Sn = (0,07s + 1) % * ceux soumis ô une telle contrainte comprise entre +10 et +20MPa seront réalisés en un alliage dont la teneur en Sn est comprise entre 0,50 % et 1,70%. Assemblage de combustible résultant de ce procédé.