| 摘要 |
In a fuel assembly having fuel rods U1 to U4, and P1 not containing gadolinium, and fuel rods G1, G2, and G3 containing gadolinium, the concentrations a of gadolinium in nuclear fuel materials A (8 wt% and 10 wt%) satisfy 0.7 < a/a max <= 1.0, the concentrations b of gadolinium in nuclear fuel materials B (5 wt% and 6 wt%) satisfy 0.4 < b/a max <= 0.7, the concentration c of gadolinium in a nuclear fuel material C (2 wt%) satisfies 0 < c/a max <= 0.4, and L(A)/5.0 >= L(B) and L(B)/5.0 >= L(C) are satisfied. The gadolinium with concentrations a, b, and c burn out respectively during the end, middle and beginnings of a cycle. L(A), L(B), and L(C) are respectively the total axial length of zones filled with the nuclear fuel materials A in the fuel rods G1 to G3, B in the fuel rods G2 and G3, and C in the fuel rod G1. |
