Patent ID: 8358733

Claim:
A support grid for a nuclear fuel assembly, said nuclear fuel assembly structured to support a generally cylindrical fuel rod with an outer diameter, said support grid comprising: a frame assembly having a plurality of outer straps and a plurality of helical frame members; wherein each said helical frame member has a helical contact portion and at least one fluted helical fuel rod contact portion, said helical contact portion having a greater diameter than the diameter of the at least one helical fuel rod contact portion, the helical contact portion structured to contact one of an adjacent helical frame member or one said outer strap, said contact portion and said fuel rod contact portion joined by a transition portion, said at least one helical fuel rod contact portion diameter being generally equivalent to said fuel rod outer diameter such that, if a fuel rod was disposed in said helical frame member, said fuel rod outer diameter would engage said helical fuel rod contact portion; wherein, if a fuel rod was disposed in said helical frame member, said at least one helical fuel rod contact portion defines an inner passage between the rod and the helical frame member, said inner passage having a helical shape; each said helical frame members coupled to an adjacent helical frame member at a contact portion, said plurality of helical frame members forming a grid; said plurality of outer straps disposed about the perimeter of said helical frame members; and said plurality of outer straps being coupled to said contact portion of each helical frame member disposed immediately adjacent to an outer strap.