Patent ID: 8509377
Filing Date: 2013-08-13
Classification: G21C,Y02E

Abstract:
1. A nuclear fuel bundle comprising: a plurality of fuel rods disposed in a channel in an axial direction; a grid spacer spanning the channel in a transverse direction at a first axial position, at least a portion of the fuel rods passing through and aligned by the grid spacer, the grid spacer being configured to frictionally grip the fuel rods; and a ferrule spacer spanning the channel in the transverse direction at a second axial position, the ferrule spacer including a plurality of ferrules, each ferrule having a circular cross-sectional shape, the ferrule spacer configured to contact less of an outer surface of the fuel rods as compared to the grid spacer, the first axial position being closer to a coolant inlet of the nuclear fuel bundle than the second axial position, at least a portion of the fuel rods passing through and aligned by the ferrule spacer, the grid spacer including a plurality of boxes, each box including at least one of mixing tabs and swirl vanes configured to increase mixing of a coolant flow as compared to the ferrule spacer, wherein no additional grid spacers exist at axial positions that are further from the coolant inlet than any spacer with ferrules.