Fuel assembly, components thereof and method of manufacture
AssigneeHitachi, Ltd.
InventorsMasahisa Inagaki, Masayoshi Kanno, Hiromasa Hirakawa, Hideaki Ishizaki, Nobukazu Yamamoto, Hideo Maki, Junjiro Nakajima, Shozo Nakamura, Satoshi Kanno
Life of this patent
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Abstract
A fuel assembly, where crystallographic orientations of a channel box are brought into a random distribution; and cladding tubes, spacers and a channel box are made from highly corrosion-resistant, Fe--Ni, zirconium-based alloy, hardened in the (.alpha.+.beta.) phase or .beta.-phase temperature region, has an average discharge burnup level of 50 to 550 GWd/t.
Claims41
A fuel assembly, which comprises a plurality of fuel rods, each comprising at least one cladding tube made from a zirconium-based alloy and a nuclear fuel loaded therein, a spacer for providing the fuel rods at desired positions, upper and lower tie plates for respectively supporting the fuel rods at their upper and lower ends, at least one water rod, and a channel box made from a zirconium-based alloy for integrating the fuel rods and the at least one water rod into one assembly, the zirconium-based alloy of the cladding tubes including iron and nickel, wherein the cladding tubes have a higher concentration of solid-solution state iron and nickel at outer surfaces of the cladding tubes than at inner surfaces, and material forming the channel box has a crystallographic orientation parameter in the normal-to-plate direction of <0001>
- crystallographic orientation of 0.25 to 0.50.
A fuel assembly, which comprises a plurality of fuel rods, each comprising a cladding tube made from a zirconium-based alloy and a nuclear fuel loaded therein, a spacer for providing the fuel rods at desired positions, an upper tie plate and a lower tie plate for supporting the thus provided fuel rods at their upper ends and their lower ends, at least one water rod, and a channel box, made from a zirconium-based alloy, for integrating the fuel rods and the at least one water rod into one assembly and encasing the assembly of the fuel rods and the at least one water rod, the cladding tubes, the spacer and the channel box each containing 1 to 2% by weight of tin, 0.20 to 0.35% by weight of iron, 0.03 to 0.16% by weight of nickel, the balance being substantially zirconium, the cladding tubes having a higher concentration of solid solution-state iron and nickel at outer surfaces of the cladding tubes than at inner surfaces thereof, and material forming the channel box having a crystallographic orientation parameter in the normal-to-plate direction of <0001>
- crystallographic orientation, as a Fr value, of 0.25 to 0.50.
A fuel assembly, which comprises a plurality of fuel rods, each comprising a cladding tube made from a zirconium-based alloy and a nuclear fuel loaded therein, a spacer for providing the fuel rods at desired positions, an upper tie plate and a lower tie plate for supporting the thus provided fuel rods at their upper ends and their lower ends, at least one water rod, and a channel box, made from a zirconium-based alloy, for integrating the fuel rods and the at least one water rod into one assembly and encasing the assembly of the fuel rods and the at least one water rod, the cladding tubes being hardened and having a higher content of solid solution-state tin, iron and nickel at outer surfaces of the cladding tubes than at inner surfaces thereof, and material forming the channel box having a crystallographic orientation parameter in the normal-to-plate direction of <0001>
- crystallographic orientation, as a Fr value, of 0.25 to 0.50.
A fuel assembly, which comprises a plurality of fuel rods, each comprising a cladding tube made from a zirconium-based alloy and a nuclear fuel loaded therein, a spacer for providing the fuel rods at desired positions, an upper tie plate and a lower tie plate for supporting the thus provided fuel rods at their upper ends and their lower ends, at least one water rod, and a channel box made from a zirconium-based alloy for integrating the fuel rods and the at least one water rod into one assembly and encasing the assembly of the fuel rods and the at least one water rod, material forming the channel box having a crystallographic orientation parameter in the normal-to-plate direction of <00021>
- crystallographic orientation, a Fr value, of 0.25 to 0.50 and being fixed to the upper tie plate, and the at least one water rod being fixed to the upper tie plate and the lower tie plate at its both ends, respectively, and material forming the at least one water rod having a crystallographic orientation parameter in the normal-to-plate direction of <0001>
- crystallographic orientation, as a Fr value, of 0.25 to 0.50.
A fuel assembly, which comprises a plurality of fuel rods, each comprising a cladding tube made from a zirconium-based alloy and a nuclear fuel loaded therein, a spacer for providing the fuel rods at desired positions, an upper tie plate and a lower tie plate for supporting the thus provided fuel rods at their upper ends and their lower ends, at least one water rod, and a channel box, made from a zirconium-based alloy, for integrating the fuel rods and the at least one water rod into one assembly and encasing the assembly of the fuel rods and the at least one water rod, the cladding tubes being hardened and having a higher content of solid solution-state iron and nickel at outer surface of the cladding tubes than at inner surfaces thereof, and the channel box being thicker at corners than on sides thereof, and material forming the channel box having a crystallographic orientation parameter in the normal-to-plate direction of <0001>
- crystallographic orientation, as a Fr value, of 0.25 to 0.50.
A fuel assembly, which comprises a plurality of fuel rods, each comprising a cladding tube made from a zirconium-based alloy and a nuclear fuel loaded therein, a spacer for providing the fuel rods at desired positions, an upper tie plate and a lower tie plate for supporting the thus provided fuel rods at their upper ends and their lower ends, at least one water rod, and a channel box made from a zirconium-based alloy for integrating the fuel rods and the at least one water rod into one assembly and encasing the assembly of the fuel rods and the at least one water rod, the cladding tubes being hardened to a depth not more than a half of a thickness thereof and having a higher content of solid solution-state tin, iron and nickel at outer surfaces of the cladding tubes than at inner surfaces thereof, the channel box being thicker at corners than on sides thereof and thicker at a lower level in the longitudinal direction than at an upper level, and material forming the channel box having a crystallographic orientation parameter in the normal-to-plate direction of <0001>
- crystallographic orientation, as a Fr value, of 0.25 to 0.50, and the cladding tubes, the spacer and the channel box each containing 1 to 2% by weight of tin, 0.20 to 0.35% by weight of iron, and 0.03 to 0.16% by weight of nickel, the balance being substantially zirconium.
A fuel assembly, which comprises a plurality of fuel rods, each comprising a cladding tube made from a zirconium-based alloy and a nuclear fuel loaded therein, a spacer for providing the fuel rods at desired positions, an upper tie plate and a lower tie plate for supporting the thus provided fuel rods at their upper ends and their lower ends, at least one water rod, and a channel box made from a zirconium-based alloy for integrating the fuel rods and the at least one water rod into one assembly and encasing the assembly of the fuel rods and the at least one water rod, the cladding tubes being hardened and having a higher content of solid solution-state tin, iron and nickel at outer surfaces of the cladding tubes than at inner surfaces thereof, the channel box being made from a welded straight square cylinder having a substantially uniform thickness at corners and on sides, and material forming the channel box having a crystallographic orientation parameter in the normal-to-plate direction of <0001>
- crystallographic orientation, as a Fr value, of 0.25 to 0.50, and at least one of the cladding tubes, the spacer, the channel box and the at least one water rod containing 1.2 to 1.7% by weight of tin, 0.07 to 0.20% by weight of iron, 0.05 to 0.15% by weight of chromium, and 0.03 to 0.08% by weight of nickel, the balance being substantially zirconium, or 0.1 to 1.7% by weight of tin, 0.18 to 0.24% by weight of iron and not more than 0.01% by weight of nickel, the balance being substantially zirconium.
A water rod for a fuel assembly, which is made from a zirconium-based alloy tube containing 1 to 2% by weight of tin, 0.05 to 0.15% by weight of chromium and 0.03 to 0.10% by weight of nickel, the balance being substantially zirconium, and having a crystallographic orientation parameter in the tube thickness direction of <0001>
- crystallographic direction, as a Fr value, of 0.25 to 0.50, a crystallographic orientation parameter in the tube longitudinal direction, as a Fl value, of 0.25 to 0.36, and a crystallographic orientation parameter in the tube circumferential direction, as a Ft value, of 0.25 to 0.36.
A water rod for a fuel assembly, which is made from a zirconium-based alloy tube having a crystallographic orientation parameter in the tube thickness direction of <0001>
- crystallographic direction, as a Fr value, of 0.25 to 0.50, a crystallographic orientation parameter in the longitudinal direction, as a Fl value, of 0.25 to 0.36, and a crystallographic orientation parameter in the tube circumferential direction, as a Ft value, of 0.25 to 0.36.
Dependencies are inferred from the claim text.