| abstract |
(57) [Abstract] [Purpose] To provide a plant operating method for preventing damage to a cladding by optimizing a fuel assembly for suppressing deposition of radioactive materials and reactor water. According to the present invention, fuel rods and water rods containing uranium oxide, plutonium oxide, or both oxides in a cladding tube made of a zirconium alloy of an outer layer and zirconium of an inner layer are arranged in a grid pattern, and a spacer and The fuel assembly for a light water reactor is formed by bundling with a spacer band, and a black oxide film is previously formed on the inner surface of zirconium and the outer surface of a zirconium alloy of the cladding tube. |