Patent ID: 8794302

Claim:
A nubbed support bar array for supporting the U-bend region of U-tubes in a nuclear steam generator, the U-tubes having a predetermined cross-sectional radius, each U-tube having an intrados, an extrados and a U-tube radius of curvature, the U-tube having the largest radius of curvature defining a maximum bundle radius, the U-tubes being arranged in parallel tube layers with a nubbed support bar array associated with the each tube layer, the U-bend region of each tube layer extending radially about a center of curvature from an innermost tube to an outermost tube and further defining an in-plane direction and an out-of-plane direction, the nubbed support bar array comprising: a plurality of first flat elongated bars, each of said first flat bars having an outer end and an inner end; and a plurality of nubbed support bars, each nubbed support bar comprising an elongated body having an outer end, an inner end connected to one of said plurality of first flat bars, first and second flat sides, and a plurality of nubs projecting in the out-of-plane direction from the first side; wherein the nubs have a convex shaped tube contact face relatively parallel to the tube intrados of an adjacent U-tube and a flat shaped tube contact face relatively parallel to the tube extrados of an adjacent U-tube; and wherein there is spacing between the nubs to provide assembly clearance between the nubs and U-tubes.