A technique is provided for engaging and disengaging burnable poison rods from the spider in a fuel assembly. The cap on the end of each of the burnable poison rods is provided with a shank that is received in the respective bore formed in the spider. In one illustrative embodiment, the shank is deformed to firmly secure the rod and attached shank in the spider bore. Pressing the shank in the direction of the bore axis overcomes the deformation to release the particular rod from the spider.