| 摘要 |
A nuclear reactor fuel assembly is provided to prevent a screw from rotating or falling out of the assembly in case of pre-load loss or screw fracture by accommodating crimp pockets in leg counterbore. Counterbores have a first diameter(48), a second diameter(52) and a third diameter(56). A hole(60) penetrates a top plate(30) of a bottom nozzle, and a fastener bolt shank(36) protrudes through the hole. Small holes are drilled through the top plate around the peripheral of the top hole while conforming a center of a hole(70) with the outer circumference of the bore. To form recesses, a rim with a bolt is fixed at notches or fixing pockets. The counterbore having the second diameter and the counterbore having the third diameter have the same diameter.
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