Rod cluster having improved vane configuration

Abstract

A spider assembly for supporting a corresponding rod cluster in a pressurized water reactor vessel, through which the core outlet flow passes in a predetermined direction. Each spider assembly comprises a generally cylindrical, central hub disposed in parallel axial relationship to the predetermined direction of the core outlet flow and a plurality of vane assemblies. Each vane assembly comprises means for mounting at least one rod to the assembly and at least one vane element connecting the rod mounting means to the hub. Each vane element has generally parallel, major planar surfaces disposed parallel to the predetermined direction of flow and a square trailing edge configuration which mitigates the shedding forcing function on the spider resulting from the core outlet flow thereover, while maximizing material content and thereby the strength thereof. Further, each vane element defines a plane of symmetry intermediate the major planar surfaces thereof and a leading edge cross-sectional configuration which is non-symmetrical relative to the associated plane of symmetry and preferably which is substantially uniform and defines a flow stagnation line which is off-set from the plane of symmetry. Corresponding vane elements, extending in generally diametrically opposite directions from the hub and having aligned planes of symmetry, have flow stagnation lines which are offset in a common direction from the aligned, respective planes of symmetry; alternatively, adjacent pairs of equiangularly displaced vane elements may have oppositely directed such offsets, commonly for all such pairs.