Patent Number: 063209233
Section: abstract

A locking device for use in restraining a jet pump downcomer of a nuclear reactor, including an upper jaw; a lower jaw placed in an opposing position below the upper jaw; and a tightening screw movably supporting the upper jaw and the lower jaw. When installed on a jet pump downcomer, the complete assembly includes a restraining ring; a downcomer carried by the restraining ring; a wedge supported by the restraining ring and the downcomer; and a guide bolt extending in an axial direction in relation to the downcomer such that the wedge is movably supported by the guide bolt. The wedge is interposed between the upper jaw and the lower jaw, and one end of the upper jaw and a corresponding end of the lower jaw are moveably supported by the guide bolt. The upper jaw and lower jaw are supported at their respective opposite ends by the tightening screw. When the tightening screw is adjusted to cause the upper jaw and lower jaw to move toward one another, the bottom surface of the recess is brought into contact with the retaining ring. This action forces the wedge and restraining ring into frictional engagement, resulting in the wedge being firmly held against the downcomer. Thus, this frictional engagement causes the downcomer, wedge, and restraining ring to be secured in a desired position.