Patent Number: 053032764
Section: abstract

Fuel assembly including deflector vanes for deflecting a component of a fluid stream flowing past such fuel assembly. The fuel assembly comprises a lattice member having rhombic-shaped rod cells and generally rhombic-shaped thimble cells therethrough. A plurality of parallel fuel rods extend through respective ones of the rod cells and a plurality of parallel control rod guide thimble tubes extend through respective ones of the thimble cells. A plurality of deflector vanes are associated with each rod cell and are integrally attached thereto on the upstream edge of each rod cell. Each deflector vane extends above its associated rod cell and curvilinearly protrudes partially over the rod cell for deflecting a component of the fluid stream onto the exterior surface of the fuel rod that extends through the rod cell. The deflector vane and the rhombic shape of each rod cell coact to create a vortex centered about the longitudinal axis of the fuel rod for maintaining liquid substantially single-phase fluid flow along the exterior surface of the fuel rod, such that DNB is avoided even in the presence of high heat fluxes across the exterior surface of the fuel rod.