| 摘要 |
PURPOSE:To shorten the working time near a fuel rod by connecting support lattices, a sleeve fixed to an upper nozzle, and a control rod guide pipe in sequence via the pipe expanding action. CONSTITUTION:A lower nozzle 2 and multiple support lattices 3 are arranged in the prescribed state, many fuel rods 5 are inserted into lattice spaces, and an upper nozzle 1 is set at the prescribed position. A sleeve 7 is inserted into the end plate of the upper nozzle 1 from below and fixed by welding. The control rod guide pipe 4 is inserted into the nozzle 1, the lattice 3 with a sleeve 8, and a lattice 3 with an insert 9, then the end plug of the guide pipe 4 stored in the insert 9 and the nozzle 2 are connected with thimble screws. The sleeves 8 fitted to the lattices 3 except for the lowermost lattice 3, the sleeve 7, and the guide pipe 4 are fixed in sequence via the pipe expanding action. Symbols B, A indicate pipe expansion sections respectively. The lattices 3 except for the lattice 3 at the lowest section, the nozzle 1, and the guide pipe 4 can be quickly and surely connected in one process. |
