Patent Number: 052895130
Section: abstract

Method of making a fuel assembly lattice member and the lattice member made by such method. The method includes placing a plurality of elongate metal straps on a computer controlled conveyor which successively conveys the straps into alignment with each of a plurality of computer controlled piercing and drawing dies belonging to a progressive die machine. The dies are selectively actuated by the computer to form such elements as curved deflector vanes and spring members on each strap member. After the piercing and drawing operations are completed, the straps are joined by welding to form a lattice member of hexagonal cross section, the lattice member defining a plurality of rhombic-shaped fuel rod cells and a plurality of generally rhombic-shaped guide tube thimble cells therethrough. The rod cells are capable of receiving respective ones of a plurality of fuel rods and the thimble cells are capable of receiving respective ones of a plurality of thimble tubes. The rhombic shape of the rod cells cooperate with the deflector vanes to deflect a component of a fluid stream about the longitudinal center axis of each fuel rod for maintaining liquid substantially single-phase fluid flow over the surface of each fuel rod in order to avoid Departure from Nucleate Boiling (DNB) on the surface of the fuel rods.