| 摘要 |
<p>The arrangement comprises a cluster of control rodlets containing neutron absorber material and arrayed for insertion thereof into guide thimbles of the fuel assembly.
<??>The cluster of control rodlets (32) has a higher axial worth at an upper portion than at a lower portion thereof. The worth of the control rod cluster varies, in one embodiment, in accordance with different lengths of the absorber material contained in the rodlets; in another embodiment, in accordance with different variations in density of the absorber material within the rodlets; in still another embodiment, in accordance with different kinds of absorber material within the rodlets; and in yet another embodiment, in accordance with different variations in diameter of the absorber material within the rotlets.</p> |
