Abstract: A self-powered in-core detector arrangement for measuring flux in a nuclear reactor core includes a first in-core detector and a second in-core detector. The first in-core detector includes a first flux detecting material, a first lead wire extending longitudinally from a first axial end of the first flux detecting material, a first insulating material surrounding outer diameters of the first flux detecting material and the first lead wire and a first sheath surrounding the first insulating material. The first sheath includes a first section surrounding the first flux detecting material and a second section surrounding the first lead wire. The first section of the first sheath has a greater outer diameter than the second section of the first sheath.

Abstract: A method for restraining a sleeve lining a tube passing through a nuclear reactor pressure vessel is provided. The method includes attaching in situ a radial protrusion on an external surface of the sleeve; and attaching a collar to an end of the tube and coupling the radial protrusion with the collar to retain the thermal sleeve in position.

Abstract: A method for peening an obstructed region of a metal assembly that is obstructed by an obstructing part of the metal assembly is provided. The method includes determining an optimal peening path for treating the obstructed region irrespective of the obstructing part; identifying a portion of the obstructing part within the optimal peening path; determining a section of the portion of the obstructing part that is removable without affecting a mechanical integrity and functionality of the obstructing part; removing, by machining, the section so as to create additional space along the optimal peening path; and peening the obstructed region, a path of the peening at least partially crossing through the additional space. A method for peening a nuclear reactor pressure vessel is also provided.

Abstract: An unlatching tool configured for actuating a movable section of a control rod drive shaft in a pressurized water reactor includes a base; a gripper assembly configured for gripping the movable section of the control rod drive shaft; a rod movably connecting the gripper assembly to the base; and a mechanical actuator fixed to the base and configured for rotating the rod to raise and lower the gripper assembly. A method for actuating a movable section of a control rod drive shaft includes installing an unlatching tool on the control rod drive shaft; latching the unlatching tool to a stationary section of the control rod drive shaft; and raising a rod connected to a gripper assembly to cause the gripper assembly to grip the movable section and move the movable section upward.

Abstract: A securing device is installable on an outer circumferential surface of a nuclear reactor core shroud and in contact with an inner circumferential surface of a pressure vessel. The securing device includes a base configured for contacting the outer circumferential surface of the nuclear reactor core shroud. The securing device also includes a radial extender including an actuator, a stationary support section fixed to the base and a movable contact section. The radial extender is configured such that the movable contact section is movable along the stationary support section by the actuator to force the movable contact section radially into the inner circumferential surface of the pressure vessel.

Abstract: An detector-assembly for measuring flux in a nuclear reactor core includes self-powered in-core detector arrangements each for measuring flux at a different one of a plurality of axial locations in the core, and an assembly connector configured to be connected to a power plant connector. The assembly connector includes a plurality flux signal terminals each connected to one of self-powered in-core detector arrangements. At least one of the self-powered in-core detector arrangements comprises a set of at least two self-powered in-core detectors for measuring flux at a same one of the axial locations in the nuclear reactor core. Each of the at least two self-powered in-core detectors includes a sheath, a detector material section inside the sheath, an insulator between the sheath and the detector material, and a flux signal output line. The flux signal output lines of the at least two self-powered in-core detectors are joined together.

Abstract: A distance sensor unit is also provided. The distance sensor unit includes an array of distance sensors configured to identify surface irregularities deviating from an expected nominal geometry of a surface as the distance sensor unit is moved along the surface and a handheld housing configured for being gripped by an operator. The array of distance sensors is connected to the handheld housing. The distance sensor unit also includes at least one surface irregularity indicator configured for providing an alert to the operator as the distance sensor unit moves over one of the surface irregularities deviating from the expected nominal geometry of the surface.

Abstract: A method for sealing an opening extending radially from an outer circumferential surface to an inner circumferential surface of a tubular object in a nuclear power plant includes inserting a stopper from outside of the outer circumferential surface through the opening into the tubular object; and actuating a fastener from the outside of the circumferential surface to force the stopper radially outward to seal the opening. A mechanical seal assembly for plugging an opening in a tubular object by contacting an inner circumferential surface of the tubular object includes a stopper configured for insertion into an interior of the tubular object for plugging the opening. The stopper includes a surface configured for matching the inner circumferential surface of the tubular object.

Abstract: A dry FCVS for a nuclear reactor containment is provided. The dry FCVS includes a housing and a round and/or elongated aerosol filter inside the housing for removing contaminant aerosols from gas passing through the housing during venting of the containment. The housing includes at least one inlet portion configured for directing gas into the aerosol filter during the venting of the containment and an outlet portion for gas filtered by the aerosol filter during the venting of the containment. The dry filtered containment venting system is arranged and configured such that when a flow of gas through the outlet portion is closed off at least one of convective, radiant and conductive heat transfer removes decay heat of aerosols captured in the aerosol filter.

Abstract: A method for filtering radiation on a CCD based camera inspection video, the method including: capturing video signals via the camera; converting the video signals to a plurality of digital video frames; identifying radiation bright spots, defined as xnoids, in a pixel of at least one of the frames, replacing the xnoids and surrounding pixels with corresponding pixels of another of the frames to create a filtered frame. A system for the inspection of a nuclear power plant comprising: a camera; and a computer, the computer configured to execute identifying xnoids in a pixel of at least one digitized video frame and replacing the xnoids and surrounding pixels with corresponding pixels of another of the frames to create a filtered frame.

Abstract: A clamp sealing apparatus configured for preventing leakage from a defective region of a tube is provided. The clamp sealing apparatus includes a first clamping section and second clamping section tangentially connected to each other; and a seal held by the first and second clamping sections. Each of the first and second clamping sections includes a segment of a clamp body and a segment of a compression section. The clamp body and the compression section is configured for axially compressing the seal between the clamp body and the compression section such that the seal is pressed radially against an outer diameter surface of the tube onto the defective region by the axial compression to seal the defective region. A method of sealing a defective region of a tube to prevent fluid leakage through the defective region is also provided.

Abstract: A probabilistic method for determining an operability interval for fasteners in a nuclear power plant assembly is provided.

Abstract: A sealing device for a jet pump of a boiling water reactor is provided. The jet pump includes an inlet mixer and a diffuser receiving the inlet mixer at a slip joint such that an outer circumferential surface of the inlet mixer is received in an inner circumferential surface of the diffuser at the slip joint. The diffuser includes a plurality of guiding fins, each guiding fin including a radially inner surface, a radially outer surface and lateral surfaces extending radially between the inner and outer surfaces. The sealing device includes a seal configured for sealingly contacting the outer circumferential surface of the inlet mixer and a collar configured for holding the seal against the outer circumferential surface of the inlet mixer. The collar includes portions configured for being received radially between the radially inner surfaces of the guiding fins and the outer circumferential surface of the inlet mixer.

Abstract: The invention is a process of repairing cracked or microstructurally damaged portions of irradiated materials, such as nuclear reactor pressure vessels and shrouds. A damaged portion of the irradiated substrate is first removed, such as by electrical discharge machining (EDM). After removing the damaged portion, the recast layer inherent in the EDM process is then removed. Once the repair area substrate material has been removed to a calculated depth, the created cavity is then filled without releasing transmutated elements within the irradiated material. A chamber may be placed on the irradiated material surrounding the repair area to create an isolated work space.

Abstract: A control rod drive replacement device includes a channel for mounting on a support under a nuclear reactor pressure vessel and a control rod drive extractor removably received in the channel. The control rod drive extractor includes a base and a housing pivotably connected to the base. The housing is configured for receiving a control rod drive. The base includes a base axis. The housing is pivotably attached to the base at the base axis for pivoting between a horizontal orientation in which the housing is aligned within the channel and a vertical orientation in which the housing is aligned for receiving the control rod drive from the nuclear reactor pressure vessel. The housing is vertically movable with respect to the base in the vertical orientation.

Abstract: A sealing device is provided to form a sealed region about one or more surfaces to be treated. The sealing device has an open end with a rim configured to matingly engage a treatment surface. The sealing device is braced both vertically and laterally, and the sealed region is flooded and pressurized. A peening nozzle and manipulating tooling are positioned within an interior volume of the sealing device. Pressurized fluid is ejected from the nozzle causing the formation of cavitation bubbles. The nozzle flow causes the cavitation bubbles to settle on the surfaces to be treated. The collapsing impact of the cavitation bubbles imparts compressive stress in the materials of the treatment surfaces.

Abstract: A nuclear fuel cladding is provided. The nuclear fuel cladding includes a base cladding; and at least one nanomaterial layer deposited on a surface of the base cladding, the nanomaterial layer having an average grain size of between 5 to 400 nanometers. A method of manufacturing nuclear fuel cladding is also provided. The method includes depositing nanoparticles on a base cladding to form at least one nanomaterial layer, the nanoparticles having an average grain size of between 5 to 400 nanometers.

Abstract: A sealing member is provided to create a sealed region about an annulus formed between an inner body, such as a thermal sleeve, and an outer body, such as a control rod drive housing nozzle. Liquid is introduced into the sealed region to create a flooded region, which is pressurized to a desired level. A nozzle is provided into the flooded region, the nozzle being configured to fit within the annulus. Pressurized fluid is ejected from the nozzle, causing the formation of cavitation bubbles. The nozzle flow causes the cavitation bubbles to settle on the surfaces forming the annulus. The collapsing impact of the cavitation bubbles imparts compressive stress in the materials of the surfaces forming the annulus.

Abstract: A fuel rod for a nuclear fission reactor is disclosed and claimed. The fuel rod includes an elongate hollow cladding configured to retain a nuclear fuel therein. The cladding includes an elongate hollow tube. Fiber layers are positioned around the outside surface of the tube or within the tube forming an integral part thereof. Both the tube and the fibers are formed of a ceramic material. A fuel assembly including a plurality of such fuel rods is also disclosed and claimed.

Abstract: The invention is an innovative design/repair methodology for PWR piping nozzles and vessel nozzles that are attached to the piping/vessel base material with a full penetration weld joint geometry. The development of a robust repair methodology for nozzles of this configuration is necessary due to plant aging, potential material degradation in the original materials of construction, potential increased nondestructive examination requirements, and PWSCC phenomena in the susceptible original materials of construction. The purpose/objective of the repair methodology is to provide a means of partially replacing the existing pressure boundary susceptible materials with PWSCC-resistant materials to facilitate the long-term repair life of the plant. The invention may be applied to a plurality of nozzle, piping, and vessel sizes with a full penetration weld joint.