Segmented instrumentation tube including a locking sleeve for interlocking the segments of the instrumentation tube, so that the threaded ends of the instrumentation tube do not unthread when subjected to vibration, such an instrumentation tube being suitable for use in a nuclear reactor pressure vessel. The instrumentation tube has a first member having a threaded end portion that has a plurality of first holes circumferentially around the outside surface thereof. The instrumentation tube also has a second member having a threaded end portion that has a plurality of second holes circumferentially around the outside surface thereof. The threads of the second member are caused to threadably engage the threads of the first member for defining a threaded joint therebetween. A sleeve having an inside surface surrounds the end portion of the first member and the end portion of the second member and thus surrounds the threaded joint. The sleeve includes a plurality of first projections and second projections that outwardly extend from the inside surface to engage the first holes and the second holes, respectively. The outside surface of the sleeve is crimped or swaged at the locations of the first projections and second projections such that the first projections and the second projections engage their respective holes. In this manner, independent rotation of the first member with respect to the second member is prevented, so that the instrumentation tube will not unthread at its threaded joint.
A method and an apparatus for testing, repairing or exchanging nozzles of the bottom of a reactor pressure vessel include inserting individual shielding containers into the reactor pressure vessel. Shafts pass through a shielding container and water-filled cartridges can be inserted into the shafts. Tubes for receiving probes of an in-core instrumentation are embedded into bottom plates of the remaining shielding containers and into bottoms of the cartridges. After removing a cartridge, a carrier for working tools can be introduced into the shaft. In this way the radioactive loading is considerably reduced by the probes inside or outside the reactor pressure vessel.
Control rod guide tube adapted to reduce vibration of a plurality of control rods disposed therein. The guide tube comprises an elongate housing surrounding the control rods, the housing having an opening at an end thereof for receiving a flowing fluid therethrough. The fluid has a velocity component acting transversely to the control rods sufficient to induce vibration of the control rods. However, the housing of the present invention has an intermediate portion pierced by a plurality of apertures for exit of the fluid from the housing to reduce the velocity of the fluid acting transversely to the control rods in order to reduce vibration of the control rods. As control rod vibration is reduced, control rod wear is mitigated.
A control rod drive mechanism includes a first tubular member having a first threaded portion and a first generally cylindrical outer surface, the first tubular member including a first plurality of slots spaced circumferentially on the first outer surface and extending in a direction parallel to the axis of the first tubular member, and a second tubular member having a second threaded portion and a second generally cylindrical outer surface, the second tubular member including a second plurality of slots spaced circumferentially on the second outer surface and extending in a direction parallel to the axis of the second tubular member. The first and second tubular members are axial aligned with the first and second threaded portions being engaged with each other to form a threaded joint therebetween. A locking sleeve overlaps at least a portion of the first outer surface of the first tubular member and at least a portion of the second outer surface of the second tubular member. The sleeve includes a generally cylindrical interior wall with deformed portions of the wall extending into said first and second plurality of slots. The deformed portions of the wall conform to an internal surface of each of the slots to evenly distribute circumferential loads on the locking sleeve. The invention also encompasses the method of assembling the control rod drive mechanism.
A locking device for a reactor instrumentation protective sleeve and reactor instrumentation column assembly. The locking device includes a protective sleeve coupled to the instrumentation column by a selectively operable and closeable clip assembly. The locking device also includes a locking sleeve supported by the protective sleeve. The locking sleeve is supported by the protective sleeve such that a portion of the locking sleeve covers a portion of the protective sleeve and the clip assembly.
A seal arrangement for providing a seal between a nuclear reactor in-core instrument housing and an instrument contained within the housing includes a lower seal assembly surrounding an outer portion of the in-core instrument housing, an upper seal assembly surrounding an outer portion of the in-core instrument, a seal housing enclosing the lower and upper seal assemblies, and lower and upper compression assemblies positioned on respective ends of the seal housing. The compression assemblies each include a drive nut and a compression collar. The compression collars engage and apply an axial load on the seal assemblies to maintain a reliable seal between the seal housing and the outer portion of the in-core instrument housing, and between the seal housing and the outer portion of the in-core instrument.
