Abstract: A disc drive, includes a base, a disc stack rotatably attached to the base, and an actuator assembly movably attached to the base. The actuator assembly also includes a bearing housing, head mounting arms, head suspensions attached to the head mounting arms and a head assembly attached to the head suspension. The disc drive also includes a hub having a cylindrical body. The hub includes a disc mounting flange on one end of the hub. A disc has an opening therein sufficient to allow the hub to fit within the opening of the disc. The disc has two substantially flat data surfaces. The disc also includes a disc clamping portion located near the opening in the disc. A clamp is used to attach the disc to the hub. At least one disc is placed onto the hub and onto the mounting flange of the hub. The clamp is then used to clamp the disc to the hub. The disc clamping portion includes features for accommodating differences in flatness between the disc surfaces, the mounting flange of the hub and the clamp.

Abstract: A control rod guide tube mounting pin for engaging a hole in an upper core plate of a nuclear reactor pressure vessel has a resilient tubular portion with one or more axial crimps which flex allowing for resiliently fitting into a hole in an upper core plate without needing to enlarge or other machine the existing holes or drilling additional holes. Stainless steel mounting pins may be backfit into existing two pin mounting systems of control rod guide tubes adjacent to the outlet nozzles of the pressure vessels by removing the pins mounting the guide tubes adjacent the outlet nozzles to the upper core support plate; and then replacing the removed pins with stainless steel replacement pins.

Abstract: An improved disc clamping system for the elements of the disc stack in a disc drive to increase resistance to radial shifting of the disc stack elements. The increased resistance to radial shifting is achieved by increasing the coefficient of friction between adjacent disc stack elements, and the increase in the coefficient of friction is accomplished by controllably texturing the contact surfaces of various disc stack elements or combinations of disc stack elements. Surface texturing processes particularly suited to specific disc stack elements are disclosed.

Abstract: A new system is provided for control rod guidance support with wear mitigating features in a nuclear reactor pressure vessel.The upper guide tube and the lower guide tube structures house the control rod when it is withdrawn from the fuel core.The upper guide tube has a top enclosure plate with a drive rod opening therethrough sized to provide a predetermined clearance space between the drive rod and the top enclosure plate and to direct coolant flow between the upper and outlet plenums and through the guide tube assembly to allow transmittal of upper plenum bypass cooling flow to the outlet plenum.Structure is provided for restricting coolant flow through the top plate clearance space to reduce control rod wear. A coupler secures the drive and control rods in end-to-end relation within the guide tube assembly. The coupler is located just below the top guide tube enclosure plate with the control rod fully withdrawn.