| 摘要 |
<p>A nuclear fuel assembly for a nuclear reactor has a plurality of vertically extending fuel rods (14) arranged side by side in a square array. The array has two first sides (AB,AC) which, in the intended arrangement of the fuel assembly in a reactor core, are adjacent a control rod region (11) and two second sides (BD,CD) which are not adjacent a control rod region. Before start of burn-up of the fuel, a plurality (1,2,3,4) of the rods (14) contain fissile plutonium and a plurality (G) of said rods (14) contain a burnable poison. When the array is considered as divided by a diagonal line connecting the two corners (B,C) at which one first side meets one second side so as to define a first region lying between the diagonal line and the first sides and a second region lying between the diagonal line and the second sides, (a) the average fissile plutonium enrichment in the fuel rods (1,2,3,4) containing plutonium is lower in the first region than the second region and (b) the number of the rods (G) containing burnable poison is higher in the first region than the second region. This permits increase of total plutonium content, while reducing the number of plutonium rod types required. <IMAGE></p> |
