Patent Number: 054815789
Section: abstract

A fuel bundle and lower tie plate assembly for a nuclear reactor includes a plurality of fuel rods supported between an upper tie plate and a lower tie plate assembly, the lower tie plate assembly including an upper grid portion and a lower body portion, the upper grid portion having a plurality of fuel rod supporting bosses interconnected by a plurality of webs thus forming flow openings between the bosses. The body portion includes an inlet nozzle and a peripheral wall extending between the bottom nozzle and the upper grid portion to define a flow volume therein. A debris catcher, including a plurality of perforated tubes, is incorporated into the lower tie plate assembly, such that one of the tubes is in abutment with a respective lowermost end of each of the plurality of fuel rod supporting bosses. The tubes are attached to a plate formed with openings corresponding to the open lower ends of the tubes so that coolant is forced to flow through the tubes in order to pass through the grid portion of the lower tie plate. The openings in the tubes cause the coolant to change direction, thus trapping debris in the tubes and effectively preventing debris from passing through the lower tie plate assembly.