| 摘要 |
PROBLEM TO BE SOLVED: To suppress local corrosion and obtain durability by imparting an oxidation film of thickness of a specific value or more to the whole surface of the fuel channel box of a fuel assembly for a boiling water reactor. SOLUTION: A fuel assembly comprises fuel rods 2, upper and lower tie plates 5, 6, a fuel channel box 1 and the like. The fuel rod 2 and a water rod 7 are assembled by pressing and molding a plate material in the form of U- shape, and a 9×9 arrangement is formed in a channel box manufactured in a square cylinder by welding. The water of high temperature and high pressure of a reactor is circulated from the lower tie plate 6 of the channel box 1 to the upper tie plate 5. An oxidation film of at least 0.7μm is formed on the whole fuel channel box 1 by high temperature steam of 350 deg.C or higher, high temperature oxygen, high temperature air and anodic oxidation. Thereby galvanic corrosion can be suppressed.
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