| 摘要 |
A reactor core for a boiling water reactor is comprised of a plurality of elongated, mutually parallel fuel assemblies (1), each one comprising a plurality of parallel, vertical fuel rods (7a, 7b). Each fuel assembly is surrounded by a first (9a) and a second pair (9b) of gaps arranged perpendicular to each other, which during reactor operation contain water, said first pair of gaps being made with a relatively large gap width and intended to accommodate two blades (10) of a control rod (11) made with a cruciform cross section, whereas said second pair of gaps is made with a relatively smaller gap width. Each one of the fuel assemblies may be divided into four equally large assembly parts (6a-6d) with the aid of two longitudinal sections orthogonal to each other, a first assembly part (6d) having two sides adjoining said second pair of gaps. The fuel assemblies comprise fuel rods (7b) which have a relatively smaller diameter and fuel rods (7a) which have a relatively larger diameter, whereby at least one-third of the fuel rods in the first assembly part and at most one-fifth of the fuel rods in the other assembly parts have a relatively smaller diameter. <IMAGE> |
