Lower end fitting debris collector and end cap spacer grid

摘要

A fuel assembly (10) has a lower end fitting debris collector and end cap spacer grid (20) assembled in the form of a welded assembly of an "eggcrate" grid (21) and cast base (40) with hollow legs (42). Fastener seats (46) in hollow legs (42 ) permit guide tubes (14) with internally threaded ends to be joined to the upper surface of the lower end fitting debris collector (20) by means of slotted fasteners (50). End caps (22) rest on grid (21) at the intersection of slottedly interlocked bars (24 and 26). Thin strips (30) mounted in slots between bars (24) and bars (26) provide small debris catching openings in grid (21). Thick strips (30a) project upwardly between strips (30) to limit lateral movement of the end caps. Projections (70) on bars (24) prevent axial fuel rod movement by engagement of tab (70a) in circumferential groove (23) of end caps (22). Opposing capture force is provided by a wire (72) which is supported in openings in thick strips (30a) and which is received in groove (23).