Abstract: There is disclosed a grid in a nuclear fuel assembly for supporting fuel rods and thimbles, which includes a plurality of elongated straps intersecting perpendicularly with each other to define a plurality of first grid cells for supporting the fuel rods and a plurality of second grid cells for supporting the thimbles. Each grid cell has a prescribed intervening distance defined between the opposed straps. A cylindrical sleeve is arranged on at least one of the opposite ends of the strap portions defining the second grid cell and has an inner diameter generally identical to the intervening distance. There is provided an engaging unit for securing each sleeve to the strap portions. The engaging unit includes at least one first engaging portion provided on the strap portions and at least one second engaging portion provided on the sleeve. The first and second engaging portions are held in resilient engagement with each other.