The PWR fuel assembly consists of fuel rods, grids, the top nozzle, the bottom nozzle, the instru­mentation tube, and guide tubes. First, the skeleton assembly is made, which is an assembly of the instru­mentation tube and the grids. Then, the fuel rods and the guide tubes are inserted into the skeleton assembly. Finally, the top nozzle and the bottom nozzle are mounted on the guide tubes by screws.

The BWR fuel assembly consists of fuel rods, water rods, grid spacers, the upper tie plate and the lower tie plate. First, the water rods, grid spacers, and the lower tie plate are assembled. Then, fuel rods are inserted into grid spacers and tie rods are connected to the lower tie plate. Finally, the upper tie plate is mounted and connected to the tie rods with screws.

The dimensions and appearance of the fuel assem­blies are inspected and the BWR fuel assembly is attached to the channel box before loading it into a reactor.