| 摘要 |
<p>Burnable poison rods are secured to a spider to enable them to be moved longitudinally within a nuclear reactor fuel assembly, plug (35) on the end of each of the burnable poison rods being provided with a stem (43) that is received in a respective bore formed in the spider. The bore has a lower portion of diameter slightly greater than that of the stem (43), an upper portion of considerably greater diameter, and an intermediate truncated conical surface (55). A longitudinal bore (44) formed in the stem (43) from its free end and extending for about half the stem length enables the stem (43) to be deformed outwardly to firmly secure the stem in the spider bore. Pressing the stem (43) downwards in the direction of the bore axis by means of a mandrel (70-Fig. 4, not shown) overcomes the deformation to release the particular rod from the spider. <IMAGE></p> |
