Fuel assembly and fuel channel box to be used therefor and manufacturing method therefor

The fuel assembly of the present invention comprises fuel rod bundles in which uranium or plutonium-containing nuclear fuel rods are aligned, a channel box which surrounds the fuel rod bundles and a water rod, a burnable poison is disposed at least to either of them, and the burnable poisons are buried so as not to be in contact with a reactor water directly. Alternatively, the burnable poisons are coated with a corrosion resistant metal such as zircaloy so as not to be in contact with reactor water directly. Specifically, the burnable poison of the channel box and the water rod comprise a metal, an alloy, an intermetallic compound or ceramics, and the metal, alloy, intermetallic compound or ceramics contains at least one of cadmium, samarium, boron, cadmium, silver, indium and hafnium. (N.H.)