Abstract:
A fuel assembly for nuclear reactors is formed of a polygonal sheathing tube and a bundle of fuel pins inside the tube. The pins are provided with helically wound spacer elements of equal pitch. The fuel pins are of two different types, pins of type B having one more spacer element than those of type A. Each pin of type A is surrounded by six pins of type B, and each fuel pin of type B, except those at the sides of the bundle, is surrounded by alternate pins of types A and B.