| 摘要 |
PROBLEM TO BE SOLVED: To provide a simple screw of a fuel assembly for reconciling a speed reduction effect of a falling speed of a control rod inserted at scrum time and cooling performance of an NFBC. SOLUTION: This simple screw of the fuel assembly is constituted so as to make a coolant to flow in the drain hole direction of a tip part from a spot facing hole of a seat part when operating a nuclear reactor, and make the coolant to flow in the spot facing hole direction of the seat part from a drain hole at scrum time, and prevents looseness of a lower nozzle by a rotation stopping pin in the seat part, and is constituted by arranging a water receiving work part on the hole part side of the rotation stopping pin for increasing a pressure loss in the coolant at scrum time. |
