US 12,437,884 B2
Nuclear fuel rod having cladding with varying diameter
Cenk Guler, Irwin, PA (US); and Yixing Sung, Monroeville, PA (US)
Assigned to Westinghouse Electric Company LLC, Cranberry Township, PA (US)
Filed by Westinghouse Electric Company LLC, Cranberry Township, PA (US)
Filed on May 19, 2021, as Appl. No. 17/324,904.
Prior Publication US 2022/0375632 A1, Nov. 24, 2022
Int. Cl. G21C 3/06 (2006.01); G21C 3/17 (2006.01)
CPC G21C 3/06 (2013.01) [G21C 3/17 (2013.01)] 11 Claims
OG exemplary drawing
 
1. A variable diameter fuel rod of a nuclear reactor assembly, the variable diameter fuel rod comprising:
a sealed elongated cladding tube; and
a plurality of fuel pellets positioned within the elongated cladding tube, wherein the plurality of fuel pellets comprise:
a plurality of solid fuel pellets; and
a plurality of annular fuel pellets, wherein an outside diameter of each of the plurality of solid fuel pellets and an outside diameter of each of the plurality of annular fuel pellets is the same, and wherein the sealed elongated cladding tube comprises:
an axial region, wherein the plurality of solid fuel pellets are positioned in the axial region; and
an axial reflector region positioned above the axial region, wherein the plurality of annular fuel pellets are positioned in the axial reflector region, wherein neutrons are reflected by the plurality of annular fuel pellets to the axial region, wherein the sealed elongated cladding tube defines a first inner cladding diameter di1 along the entire axial region and a second inner cladding diameter di2 at a top end of the axial reflector region, wherein the second inner cladding diameter di2 is greater than the first inner cladding diameter di1, and wherein the axial reflector region defines a sloped surface of the sealed elongated cladding tube between the first inner cladding diameter di1 and the second inner cladding diameter di2, wherein a first annular gap is defined between the outside diameter of a first annular fuel pellet of the plurality of annular fuel pellets and the sloped surface of the sealed elongated cladding tube, wherein a second annular gap is defined between the outside diameter of a second annular fuel pellet of the plurality of annular fuel pellets and the sloped surface of the sealed elongated cladding tube, wherein the first annular gap is positioned above the second annular gap, and wherein the first annular gap is larger than the second annular gap.