FUEL ASSEMBLY AND CORE OF LIGHT WATER REACTOR LOADED WITH FUEL ASSEMBLY

• Main Author: MIWA JUNICHI
• Format: Patent
• Language: English; Japanese
• Published: 26.09.2019
• Subjects: NUCLEAR ENGINEERING; NUCLEAR PHYSICS; NUCLEAR REACTORS; PHYSICS

To provide a fuel assembly capable of improving a minor actinide combustion efficiency while reducing the maximum line output density in a light water reactor having hardened a neutron spectrum during operation, and a core of the light water reactor in which the fuel assembly is loaded.SOLUTION: A fuel assembly 1 in which a plurality of fuel rods 3 are arranged in a triangular fashion in a square channel box 2 in a cross-section and which is loaded into a reactor core 22 of a light water reactor has a high deceleration region 7 having a high deceleration effect on neutrons due to light water, a low deceleration region 8 having a low reduction effect on neutrons due to light water. An average weight ratio of the minor actinide in heave metals obtained by adding uranium, plutonium, and minor actinide in the fuel rod 3 arranged in the high deceleration region 7 is larger than the average weight ratio of the minor actinide in heave metals obtained by adding uranium, plutonium, and minor actinide in the fuel rod 3 arranged in the low deceleration region 8.SELECTED DRAWING: Figure 5 【課題】運転中に中性子スペクトルを硬化させた軽水炉において最大線出力密度を低減しつつ、マイナーアクチニド燃焼効率を向上し得る燃料集合体及びそれを装荷する軽水炉の炉心を提供する。【解決手段】横断面が正方形状のチャンネルボックス２内に複数の燃料棒３が三角稠密配置され、軽水炉の炉心２２に正方格子状に装荷される燃料集合体１は、軽水による中性子に対する減速効果の大きい高減速領域７及び軽水による中性子に対する減速効果の小さい低減速領域８を有し、高減速領域７に配される燃料棒３のウランとプルトニウムとマイナーアクチニドを足し合わせた重金属中のマイナーアクチニドの平均重量割合が、低減速領域８に配される燃料棒３のウランとプルトニウムとマイナーアクチニドを足し合わせた重金属中のマイナーアクチニドの平均重量割合より大きい。【選択図】 図５