Patent Number: 047175290
Section: abstract

A thimble guide assembly for use in a nuclear reactor includes a lower element which can be screwed into a bore in a core plate and an upper element which can be screwed to the lower element. One of the screw-connections is right-handed while the other is left-handed. The length of the upper element is selected so that the exposed portion of a thimble tube, which extends through the thimble guide assembly and into a fuel assembly above it, is relatively modest, thereby minimizing the turbulence to which the thimble tube is exposed. The lower element of the thimble guide assembly is provided with a sleeve portion which extends through the bore in the core plate, and the tip of the upper element terminates in a planar, annular lip. Both elements are provided with surfaces for engagement by wrenches or other tools. The lower element has annular grooves for engagement by a lower spring clip which is welded to the core plate and an upper spring clip which is welded to the upper element.