US 5,068,082 A · Fuel assembly for nuclear reactor

Abstract

A fuel assembly for a nuclear reactor includes a number of fuel rods filled with a fuel material. A plurality of fuel rods have a partial effective fuel area filled with a fuel material and has a portion in which enrichment of a fissile nuclide is significantly reduced or the fissile nuclide does not exist at all on an axial level including a reactor shut-down zone at which subcriticality becomes small during a reactor operation period. The other fuel rods are filled with the fuel material throughout the entire axial length thereof. The first mentioned fuel rod may be provided with a partially interposed zone or may be constructed by a fuel rod having a length shorter than that of the other fuel rod. The tube means may be arranged in the fuel assembly so as to pass the moderator therethrough.

Claims59

Dependent claims

A fuel assembly for a nuclear reactor of the type in which a number of fuel rods, each constructed by filling a clad with a fuel material, are arranged in a bundle, comprising:

a plurality of first fuel rods having a partial effective fuel area filled with a fuel material and having a portion in which enrichment of a fissile nuclide in the clad of the fuel rod is significantly reduced, or the fissile nuclide does not exist at all, positioned on an axial level including a portion at which subcriticality becomes small at a period in which maintenance of reactor shut-down margin is small during a reactor operation period;
and
a plurality of second fuel rods having a total effective fuel area filled with a fuel material throughout an entire axial length of the clad of the fuel rod, wherein said first fuel rods are disposed in straight lines inside the bundle so as to horizontally separate said second fuel rods into a plurality of sub-bundles.

A fuel assembly for a nuclear reactor of the type in which a number of fuel rods, each constructed by filling a clad with a fuel material, are arranged in a bundle, comprising:

a plurality of first fuel rods having a partial effective fuel area filled with a fuel material and having a portion in which enrichment of a fissile nuclide in the clad of the fuel rod is significantly reduced, or the fissile nuclide does not exist at all, positioned on an axial level including a first section at which subcriticality becomes small at a period in which maintenance of reactor shut-down margin is small during a reactor operation period and a second section located between said first section and a lower end of the effective fuel area;
and
a plurality of second fuel rods having at least one partial interposed zone in which enrichment of a fissile nuclide in the clad of the fuel rod is significantly reduced, or the fissile nuclide does not exist at all, positioned at said second section, wherein said first fuel rods are disposed inside the bundle so as to horizontally separate said second fuel rods into a plurality of sub-bundles.

Dependencies are inferred from the claim text.

Fuel assembly for nuclear reactor

Life of this patent

Fuel assembly for nuclear reactor

Life of this patent

Abstract

Claims59