Patent Number: 052672867
Section: abstract

A fuel assembly having a water cross or water rod arranged between the fuel rods, an inside of the water cross or water rod being divided into a coolant rising passage and a coolant lowering passage, and a control guide tube disposed inside the water cross or water rod and extending along an axial direction of the water cross or water rod. The coolant rising passage has a coolant inlet port formed to a portion above or under a portion at which the fuel rods are supported by the lower tie plate. The control element guide tube has a coolant outlet port formed at that portion so that a coolant introduced into the coolant rising passage flows vertically upwardly, then turns and flows downwardly along the control element guide tube, and flows into an inside thereof through the coolant outlet port. A reactor core comprises a plurality of fuel assemblies each having a structure described above, a control rod and a control element operated in association with the control rod.