| 摘要 |
PROBLEM TO BE SOLVED: To provide a fuel assembly for a pressurized water reactor capable of forming stably a coolant lateral flow for pressing and fixing control rods, suppressing vibration of the control rods, and suppressing abrasion on the outer surface of each control rod and the inner surface of each control rod guide pipe. SOLUTION: At least passage holes 15A, 15B, 15C provided on positions where the coolant collides with an overhang among passage holes on an adapter plate 6 forming a lower structure of an upper nozzle are arranged axisymmetrically in principle by using a diagonal Q of a passage surface as the axis of symmetry, and ligaments 21, 23 on the periphery of passage holes positioned on the furthermore outside and inside than a mounting opening 11a existing on the outer periphery side among mounting openings are constituted to be larger than a ligament 22 on the periphery of a passage holes positioned on both lateral sides of the mounting opening. COPYRIGHT: (C)2007,JPO&INPIT
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