FUEL AGGREGATE

• Main Authors: KATONO KENICHI, NARISHIMA YUKI
• Format: Patent
• Language: English; Japanese
• Published: 05.08.2021
• Subjects: NUCLEAR ENGINEERING; NUCLEAR PHYSICS; NUCLEAR REACTORS; PHYSICS

To provide a fuel aggregate which is arranged in a reactor core of a low-deceleration spectrum boiling-water reactor for preventing that cooling water for cooling a fuel rod is unevenly distributed and circulates in a gap which is formed between the fuel rod at an outermost circumference and a channel box.SOLUTION: A fuel aggregate has a plurality of fuel rods which are arranged in a triangular lattice space, and a square cylindrical channel box. The fuel rods have a second fuel rod arranged in a center region, and a first fuel rod arranged at a periphery of the second fuel rod. In the fuel rod, fuel having one fuel concentration is used in an effective length direction of the fuel rod, the second fuel rod fuel has two fuel concentrations in the effective length direction of the fuel rod, and the fuel concentration of the fuel at a lower part of the second fuel rod is lower than the fuel concentration of the fuel at an upper part of the second fuel rod.SELECTED DRAWING: Figure 3 【課題】本発明は、最外周の燃料棒とチャンネルボックスとの間に形成される間隙に、燃料棒を冷却する冷却水が偏在して流通することを抑制する、低減速スペクトル沸騰水型原子炉の炉心に装荷される燃料集合体を提供する。【解決手段】本発明の燃料集合体は、三角格子に配置される複数の燃料棒と四角筒状のチャンネルボックスとを有し、燃料棒は、中央領域に設置される第２燃料棒とその周囲に設置される第１燃料棒とを有し、第１燃料棒は、燃料棒の有効長方向において、一つの燃料濃縮度の燃料が使用され、第２燃料棒は、燃料棒の有効長方向において、二つの燃料濃縮度を有し、第２燃料棒の下部の燃料の燃料濃縮度は、第２燃料棒の上部の燃料の燃料濃縮度よりも、低いことを特徴とする。【選択図】 図３