Patent ID: 8311180

Claim:
A fuel assembly comprising: a fuel rod array of a plurality of fuel rods including a plurality of first fuel rods including enriched uranium and not including a burnable poison, and a plurality of second fuel rods including said enriched uranium and said burnable poison; and at least one water rod; wherein said fuel rod array has a plurality of corner sections, each corner section being a region having three fuel rods in an outermost layer of said fuel rod array including one fuel rod at a corner of said outermost layer of said corner section and two fuel rods in said outermost layer directly adjacent said one fuel rod at said corner; wherein one of said second fuel rods is said one fuel rod at said corner of a first corner section of said plurality of corner sections; wherein another of said second fuel rods is at least one of said two fuel rods directly adjacent to said one of said second fuel rods at said corner of said first corner section; wherein others of said second fuel rods are placed adjacent to said at least one water rod; wherein a second corner section of said plurality of corner sections includes a fuel rod other than one of said second fuel rods at a corner in said outermost layer that faces a control rod when said fuel assembly is loaded in a core; and wherein the number of said second fuel rods placed in said second corner section is less than the number of said second fuel rods placed in said first corner section.