Patent Number: 046845020
Section: abstract

An alignment sleeve capture arrangement in the top nozzle of a fuel assembly includes an internal cylindrical wall defining a bore through the upper hold-down plate of the top nozzle below and in communication with a passageway therein through which extends an alignment sleeve of the top nozzle which is used to attach it to the guide thimble of the fuel assembly. The bore has an inside diameter larger than the inside diameter of the passage so as to form a cavity surrounding an upper position of the alignment sleeve which extends axially through the bore as well as the passageway. Also, the arrangement includes an annular shoulder on the upper hold-down plate surrounding the alignment sleeve upper portion and defining an upper limit of the cavity. The shoulder forms a transition between the larger inside diameter of the bore and the smaller inside diameter of the passageway. Additionally, an annular retainer is attached to the upper hold-down plate and spaced below the shoulder. The retainer surrounds the alignment sleeve upper portion and has a neck portion with a central hole through which the alignment sleeve extends and defines a lower limit of the cavity. Lastly, the arrangement includes a bearing ring encircling and attached to the alignment sleeve upper portion and having an outside diameter less than the inside diameter of the cavity and greater than respective inside diameters of the shoulder and retainer neck portion which define the upper and lower limits of the cavity such that the bearing ring can slide within the cavity with the alignment sleeve between the upper and lower limits thereof as the upper hold-down plate moves along the alignment sleeve and will retain the alignment sleeve slidably attached to the hold-down plate when the sleeve is detached from the guide thimble upper end portion. The retainer also has a hollow body portion with one end attached to the hold-down plate and an opposite end integrally connected with the neck portion, the retainer body portion defining a portion of the cavity.