Fuel assembly of BWR reactor

In a BWR reactor, a fuel assembly has a plurality of fuel rods having the upper and lower ends supported by upper and lower plates, and fuel spacers which keep the distance of fuel rods are constituted with a great number of cylindrical cells each having an outer diameter smaller than the distance between the centers of adjacent fuel rods, and allowing a fuel rod to pass therethrough. Springs are welded on the inner wall of the cylindrical cell, and the springs, in combination with stoppers, support the fuel rods passing through the cylindrical cells. The cylindrical cells are joined with each other by welding by way of plate-like connecting members. With such a constitution, projection areas of the fuel spacers can be reduced without changing the plate thickness of the cylindrical cell. Accordingly, corrosion resistance of the fuel spacers can be kept and the thermal margin of the fuel assembly can be improved without leading to a great pressure loss. (I.N.)