a two phase computational fluid dynamics model has predicted that the critical heat flux performance of this grid spacer is improved relative to the conventional split vane spacer grid design illustrated in fig4 in addition the computational fluid dynamics model has predicted that the single phase pressure drop produced by this invention is significantly reduced relative to the conventional split vane spacer grid design illustrated in fig4 the streamlined torpedo body 104 has two diametrically extending slots in its lower end that are circumferentially offset by ninety degrees to fit over the grid straps 86 and 88 at the intersection 60 to which it is welded the streamlined stem 104 enhances the grid crush strength the mixing vanes are connected to the strap and the streamlined torpedo body 104 such as by welding extra support from the torpedo body 104 will enhance the structural integrity of the grid cell grids manufactured in accordance with this invention are still constructed in the conventional way with the addition of the vane assembly 102 which is slotted onto the intersection 60 at each corner of a fuel element support cell 94 and welded the addition in manufacturing costs is estimated to be low in impact fig7 is a plan view illustrating one embodiment of this invention with the springs and dimples removed to more easily focus on the vane structure with the vanes all tilted in the same direction fig8 illustrates a second.