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