Water rod for nuclear reactor and method for providing and using same

A water rod, usable for containing water in a substantially interior position in a nuclear fuel rod bundle, the bundle having a plurality of lattice positions spaced at a predetermined lattice pitch, comprising:

• a hollow longitudinally-extending tube having a sidewall which defines a cross-sectional interior region of said tube, configured to substantially occupy a predetermined number of lattice positions of the bundle;
• said cross-sectional interior region being configured to define four interiorly-extending longitudinal projections defined therebetween four exteriorly-projecting lobes;
• wherein said predetermined number is greater than four lattice positions and less than nine lattice positions;
• and
• wherein said area of said cross-sectional region, said predetermined number, and said pitch define a water rod efficiency greater than about 0.7;
• and,
• at least one projection on an exterior portion of said sidewall;
• and
• wherein said sidewall has sufficient resiliency to permit inward flexing of said sidewall, at least in a portion substantially adjacent to said projection, to permit passage of said projection over an obstruction when said water rod is axially moved proximate to said obstruction.

A water rod, usable for containing water in a substantially interior position in a nuclear fuel rod bundle, the bundle having a plurality of lattice positions spaced at a predetermined lattice pitch, comprising:

• a hollow longitudinally-extending tube having a sidewall which defines a cross-sectional interior region of said tube, configured to substantially occupy a predetermined number of lattice positions of the bundle;
• said cross-sectional interior region being configured to define a substantially rectangular shape;
• wherein said predetermined number is greater than four lattice positions and less than nine lattice positions;
• and
• wherein said area of said cross-sectional region, said predetermined number, and said pitch define a water rod efficiency greater than about 0.7.

A water rod, usable for containing water in a substantially interior position in a nuclear fuel rod bundle, the bundle having a plurality of lattice positions spaced at a predetermined lattice pitch, comprising:

• a hollow, longitudinally extending tube having a sidewall which defines a cross-sectional interior region of said tube, configured to substantially occupy a predetermined number of lattice positions of the bundles;
• said cross-sectional interior region being configured to define two substantially circular portions, said circular portions being substantially adjacent;
• wherein said predetermined number is greater than four lattice positions and less than nine lattice positions;
• and
• wherein said area of said cross-sectional region, said predetermined number, and said pitch define a water rod efficiency grater than about 0.6.

A nuclear fuel rod bundle comprising:

• first means for spatially positioning rods wherein said means defines a lattice having a plurality of lattice positions and a lattice pitch;
• a plurality of nuclear fuel rods operably connected with said means for positioning, wherein said nuclear fuel rods occupy at least some of said lattice positions;
• at least one hollow longitudinally extending tube having a sidewall which defines a cross-sectional interior region of said tube, configured to substantially occupy greater than four and fewer than nine lattice positions of said lattice;
• said cross-sectional interior region being configured to define two round-cornered triangular regions continuously connected by a constricted region, said constricted region being defined by two inwardly extending longitudinal projections;
• wherein the area of said cross-sectional region for said tubes, said number of occupied positions for said tubes, and said pitch define a water rod efficiency greater than about 0.7;
• and,
• at least one projection on an exterior portion of said sidewall;
• and
• wherein said sidewall has sufficient resiliency to permit inward flexing of said sidewall, at least in a portion substantially adjacent to said projection, to permit passage of said projection over an obstruction when said water rod is axially moved proximate to said obstruction.

A nuclear fuel rod bundle comprising:

• first means for spatially positioned rods wherein said means defines a lattice having a plurality of lattice positions and a lattice pitch;
• a plurality of nuclear fuel rods operably connected with said means for positioning, wherein said nuclear fuel rods occupy at least some of said lattice positions;
• at least one hollow longitudinally extending tube having a sidewall which defines a cross-sectional interior region of said tube, configured to substantially occupy greater than four and fewer than nine lattice positions of said lattice;
• and
• said cross-sectional interior region being configured as a rectangle;
• and
• wherein the area of said cross-sectional region of said tubes, said number of occupied positions of said tubes, and said pitch define a water rod efficiency greater than about 0.7.

A nuclear fuel rod bundle comprising:

• first means for spatially positioning rods wherein said means defines a lattice having a plurality of lattice positions and a lattice pitch;
• a plurality of nuclear fuel rods operably connected with said means for positioning, wherein said nuclear fuel rods occupy at least some of said lattice positions;
• at least one hollow longitudinally extending tube having a sidewall which defines a cross-sectional interior region of said tube, configured to substantially occupy greater than four and fewer than nine lattice positions of said lattice;
• said cross-sectional interior region being configured to define two substantially circular regions being substantially adjacent;
• and
• wherein the area of said cross-sectional region of said tubes, said number of occupied positions of said tubes, and said pitch define a water rod efficiency greater than about 0.6.