Patent ID: 8359732

Claim:
A method of manufacturing a spacer grid ( 3 ) for positioning fuel rods in a fuel assembly in a nuclear plant, which spacer grid ( 3 ) defines grid cells ( 5 ) for the fuel rods, which grid cells define a lengthwise direction ( 6 ), wherein the method comprises: manufacturing an optimized sheet metal ( 1 ) of a zirconium based alloy, wherein the optimized sheet metal ( 1 ) defines a sheet plane (BA), wherein the manufacturing of the optimized sheet metal comprises: providing a sheet metal ( 2 ) of a zirconium based alloy that comprises niobium, tin, and iron, subjecting the sheet metal ( 2 ) to at least a preparing cold rolling and a final cold rolling, wherein the preparing cold rolling and the final cold rolling are both performed in a common rolling direction, heat treating the sheet metal ( 2 ) between the preparing cold rolling and the final cold rolling so that the zirconium based alloy is partially re-crystallized, wherein the degree of re-crystallisation in the heat treatment is at least 20 percent and no more than 90 percent; cutting the manufactured optimized sheet metal ( 1 ) into metal strips ( 4 ) with their length axes (B) perpendicular to the rolling direction; and arranging the metal strips ( 4 ) to form the spacer grid ( 3 ) so that the length axes (B) of the metal strips ( 4 ) extend perpendicularly to the lengthwise direction ( 6 ) of the grid cells ( 5 ).