Patent ID: 6738447
Filing Date: 2004-05-18
Classification: G21C,Y02E

Abstract:
A high energy absorption top nozzle for a nuclear fuel assembly having support tubes extending at least partially there through, in which control rods supported by a rod control cluster assembly are slidable, said nozzle comprising:a tubular barrel having a first end and a second end and a hold-down plate circumferentially affixed to an interior wall of the tubular barrel intermediate the first and second ends of the tubular barrel and substantially spanning a central opening within the tubular barrel, said hold-down plate having an upper surface face directed toward the first end of the barrel and a lower surface face directed toward the second end of the barrel and a central opening through which an upper hub plunger assembly can pass and a plurality of secondary openings within which the support tubes can move; An assembly comprising a tubular hub having a closed end and an open end, the open end slidably positioned in the second end of said barrel, a rod ejection plate, and the support tubes rigidly securing said rod ejection plate to said hub in fixed axially aligned spaced relation, said rod ejection plate having apertures aligned with said support tubes that are attached thereto; The upper hub plunger assembly surrounding and coupled to a central tube at an upper portion thereof and extendable at least partially through the central opening in said hold-down plate, comprising a reaction plate substantially spanning the central opening within the tubular barrel and having apertures sized and aligned to slidably receive the support tubes and, in the reaction plate's upper most position adjacent the hold-down plate, the reaction plate substantially covers the lower surface face of the hold-down plate; and spring means for biasing the upper hub plunger at least partially within or just below the central opening of the hold-down plate, the reaction plate against the lower surface face of the hold-down plate and the hold-down plate a predetermined distance from the open end of the tubular hub.