Abstract: The grids (14) of a nuclear fuel assembly (10) include an outer strip, or perimeter plate (100), having outwardly projecting formations (104,106) spaced from the side edges (110) of the internal grid strips (108), for resiliently absorbing lateral forces before such forces are transferred directly to the internal strips. The load dissipating feature of the present invention can be enhanced by providing orifices (552) in the substantially flat, central region (502) of each perimeter plate. This produces an hydraulic damping effect that can be pre-established by selecting the orifice sizes for a given set of impact load conditions.

Abstract: A method for sputter coating the inside surface (30) of a fuel assembly tubular component (10) such as a control rod guide tube (200) with wear or corrosion resistant material. The steps include supporting the component tube in a fixture (12,14) and supporting a source tube (100,300) of e.g., wear resistant material, coaxially within the component tube, thereby defining a cylindrical annulus (24) between the tubes. The annular space is evacuated and backfilled with an inert working gas (26) such as argon, to a pressure sufficient to sustain a plasma discharge. The component tube is positively biased (36) as an anode, and the source tube is negatively biased (34) as a cathode, such that a plasma of the working gas is established in the annular space. A circumferential magnetic field is generated around the source tube to confine and shape the plasma whereby the source tube is bombarded with ions from the plasma substantially uniformly over the length of the source tube.

Abstract: The method of repairing in situ a damaged or malfunctioning electrical connector (10) of a safety related nuclear reactor instrument (14) and its associated sheathed cable (18) wherein the damaged or malfunctioning connector portion (20) is cut from its associated cable (18) and replaced by a new connector portion. The wires of the cut cable are connected with the replacement connector portion and are suitably insulated. The cut cable and new connector portion are then secured together by a special alloy coupling (34) which is positioned in spanning relation with the cut cable (18) and the replacement connector portion (20). This special alloy has the property that it can be expanded within limits and upon being heated above a critical temperature will return to its original dimension. The tubular coupling accordingly has an expanded diameter slightly larger than that of the replacement connector portion and the sheath of the cut cable but an original inner diameter slightly smaller.

Abstract: Apparatus (100) for pulling a projecting tube (14) from a tube sheet (12), along the tube axis (18), comprising a base (200) for engaging the tube sheet and a jacking assembly (300) mounted on the base and actuable by a first fluid pressure variation between extended and retracted positions (302) away from and toward the base respectively. A substantially annular gripper assembly (400) is connected to the jacking assembly for extended and retracted movement therewith and adapted to coaxially receive the tube. The gripper assembly includes a housing (404) having a gripper piston chamber (410) in which a second fluid pressure variation can be introduced into the gripper piston chamber. A gripper piston 420 is situated for movement in the gripper piston chamber in response to the second fluid pressure in the chamber.

Abstract: An advanced control room complex for a nuclear power plant, including a discrete indicator and alarm system (72) which is nuclear qualified for rapid response to changes in plant parameters and a component control system (64) which together provide a discrete monitoring and control capability at a panel (14-22, 26, 28) in the control room (10). A separate data processing system (70), which need not be nuclear qualified, provides integrated and overview information to the control room and to each panel, through CRTs (84) and a large, overhead integrated process status overview board (24). The discrete indicator and alarm system (72) and the data processing system (70) receive inputs from common plant sensors and validate the sensor outputs to arrive at a representative value of the parameter for use by the operator during both normal and accident conditions, thereby avoiding the need for him to assimilate data from each sensor individually.

Abstract: A flow deflector grid (10) for a nuclear fuel assembly, comprising a plurality of metal strips (12,14) which intersect in a regular array to form an egg-crate type lattice, which defines a plurality of coolant flow channels (16). Each channel has sidewalls (42,44) defined by the strips, a height dimension defined by the height of the strips, a plurality of corners (46) defined by the strip intersections (26), a channel central axis parallel to the height dimension, and a flow cross section normal to the channel axis for coaxially receiving a fuel rod (18) spaced within the channel sidewalls. A unitary flow deflector member (30) is attached to and situated in the corner of each channel so as to be cradled between first and second sidewalls.

Abstract: A method for coating the inside surface (18) of tubular components (16) of a nuclear fuel assembly, including the steps of supporting the component within a vacuum chamber (12), positioning a source rod (20) having a field emitter structure (22) within the component, the structure being formed of material to be coated on the surface, and inducing an electrical current flow (26) through the rod sufficient to evaporate at least a portion of the emitter structure, whereby the evaporated material of the emitter structure is deposited on and adheres to the surface as a coating. Optionally, the vacuum chamber is backfilled with a reactive gas (38), and the material evaporated from the emitter structure chemically reacts with the gas before adhering to the surface. The reactive gas can be one of nitrogen, oxygen, or carbon plasma and the coating adhered to the component can be one of a nitride, oxide, or carbide, respectively.

Abstract: A method for enhancing the wear and corrosion resistance of a tubular nuclear fuel assembly component (40), comprising the step of coating the component with a corrosion and wear resistant material by an anodic arc plasma deposition process (70). The coating is preferably a nitride reactively formed during the plasma deposition process. The component is preferably a nuclear fuel rod cladding tube and the coating material is one of ZrN or TiN.

Abstract: A method for sputtering coating the inside surface of a fuel assembly tubular component (10,200,400,700) with absorber material such as a burnable poison or getter. The steps include supporting the e.g., cladding tube (10) in a fixture (12,14) and supporting a source tube (100) of e.g., burnable poison material coaxially within the cladding tube, thereby defining a cylindrical annulus (24) between the tubes. The annular space is evacuated and backfilled with an inert working gas (26) such as argon, to a pressure sufficient to sustain a plasma discharge. The cladding tube is positively biased (36) as an anode, and the source tube is negatively biased (34) as a cathode, such that a plasma of the working gas is established in the annular space. A circumferential magnetic field is generated around the source tube to confine and shape the plasma whereby the source tube is bombarded with ions from the plasma substantially uniformly over the length of the source tube.

Abstract: Many pharmaceuticals require a specific tissue for injection, such as adipose or muscle, to optimize the effect of the drug. This is important to achieve the desired bioavailability of the injected substance. In some cases, intravenous injections are desired over subcutaneous and intramuscular. The invention is a bioimpedance method and apparatus for sensing a hypodermic needle's transition from subcutaneous adipose to muscle tissue. The invention could also be used to sense a vascular transition. The sensing can be integrated into instrumentation that identifies the tissue or simply signals that the transition has occurred. The physician or nurse could then confidently inject the medication into the intended tissue.

Abstract: A valve test unit (100) for attachment to a value (12) having a fluidly operated stem actuator (20a) responsive to a positioner device (24a). The unit includes a first input port (102) connectable to a source (104) of fluid pressure, a second input port (106) connectable to a source (108) of electrical power, a first output port (110) fluidly connected to the first input port, for delivering a controlled fluid pressure from the unit, and a second output port (114) electrically connected to the second input port, for delivering a controlled electrical signal from the unit. Test programs (118) are provided for converting fluid pressure, at the first input port, into a controlled, time dependent fluid pressure at the first output port and converting electrical power at the second input port into a controlled, time dependent electrical signal at the second output port.

Abstract: In a method for fabricating an end fitting (12,200) for a nuclear fuel assembly (10), wherein the end fitting includes at least one spring member (24,202) having an active external surface (32,206) for contacting rigid core support structure (100) in the nuclear reactor, the improvement comprising applying a coating to the active surface of the spring member. The coating is selected from the group consisting of nitrides, Cr, TiC, CrC, ZrC and NiTaB. The spring member is preferably Inconel and the coating is one of ZrN or TiN. Each spring member can be formed by nesting a plurality of spring elements (28,34,36 or 208,210) so that the spring elements are in contact with each other and the method includes applying said coating to each of the spring elements at least where they contact each other.

Abstract: A method for enhancing the wear resistance of a tubular component (62) of a nuclear fuel assembly, including the first steps of supporting the component in an implantation chamber (16), removing ambient air from the chamber such as by a pump (56) and generating a plasma plume (28) of positively charged metal source material by establishing an electrical discharge arc which travels from a cathode (18) of said source material to an anode (24) of a different material. At least a portion of the plasma plume is passed through an electromagnetic duct (14) which filters constituents other than free, high energy source material ions out of the plume. The high energy source material positive ions are directed through the chamber onto the negatively charged component. The chamber can be backfilled with a reactive gas such as nitrogen which forms an ionic compound with the source material ions such as Zr or Ti, and the ionic compound such as ZrN or TiN implants in the component.

Abstract: An advanced control room complex for a nuclear power plant, including a discrete indicator and alarm system (72) which is nuclear qualified for rapid response to changes in plant parameters and a component control system (64) which together provide a discrete monitoring and control capability at a panel (14-22, 26, 28) in the control room (10). A separate data processing system (70), which need not be nuclear qualified, provides integrated and overview information to the control room and to each panel, through CRTs (84) and a large, overhead integrated process status overview board (24). The discrete indicator and alarm system (72) and the data processing system (70) receive inputs from common plant sensors and validate the sensor outputs to arrive at a representative value of the parameter for use by the operator during both normal and accident conditions, thereby avoiding the need for him to assimilate data from each sensor individually.

Abstract: An advanced control room complex for a nuclear power plant, including a discrete indicator and alarm system (72) which is nuclear qualified for rapid response to changes in plant parameters and a component control system (64) which together provide a discrete monitoring and control capability at a panel (14-22, 26, 28) in the control room (10). A separate data processing system (70), which need not be nuclear qualified, provides integrated and overview information to the control room and to each panel, through CRTs (84) and a large, overhead integrated process status overview board (24). The discrete indicator and alarm system (72) and the data processing system (70) receive inputs from common plant sensors and validate the sensor outputs to arrive at a representative value of the parameter for use by the operator during both normal and accident conditions, thereby avoiding the need for him to assimilate data from each sensor individually.

Abstract: A nuclear fuel assembly grid (1) has a plurality of flat strips (10,12) that are orthogonally interlaced along vertical slots (38,60) through their upper or lower edges and welded together to form an egg crate-like array of four-walled cells (14) for receiving respective fuel rods (16), each cell including springs (20,30) and arches (32,34) projecting from the walls for contacting and supporting a respective fuel rod in the interior of the cell. At least some of the cells having flow deflection vanes (36,56) projecting integrally from a cell wall into the interior of the cell without contacting the fuel rod. Preferably, the vane is bent along a bend line (52) that is parallel to the upper edge (24) of the strip, into the interior of the cell, thereby forming an angle of between about 15 degrees and 30 degrees relative to the plane defined by the body, or plate portion of the strip.

Abstract: Equipment for acquiring diagnostic data from a valve train parameter that changes as a result of the operation of a valve (14) in a process plant is positioned as an auxiliary data acquisition unit (200) in the vicinity of the valve train. A plurality of sensor lines (P3, P4) are connected between the auxiliary unit and locations in the valve train where the parameter changes. The valve is operated so as to generate parameter signals manifested in a first physical form in the sensor lines. In the auxiliary unit, the physical form of the parameter signals is converted into diagnostic signals (E10, E11) having a different physical form. The diagnostic signals are transmitted to a base data acquisition unit (100) that is physically distinct from the auxiliary unit.

Abstract: A plug assembly for plugging the flow hole of a core support barrel employs an offset arm for securing the plug to the core support barrel above the flow hole and the adjacent thermal shield. The disclosed embodiments do not require the cutting of an access opening through the thermal shield.

Abstract: A tool which contains a pulsed accelerator neutron source and means for making timing measurements of the thermal neutron response in a localized portion of the environment immediately surrounding the borehole. Formation sigma is determined by parameterizing the detected thermal neutron decay curve, preferably with a diffusion model similar to that known in the art for determining formation sigma on the basis of gamma ray time distributions. In a more comprehensive embodiment of the present invention, which includes a gamma detector in the tool, formation sigma can be measured in parallel using both gamma ray and thermal neutron decay characteristics. Deviations between the neutron and gamma-based signals that occur as the tool traverses the borehole, provide useful indications of local effects immediately surrounding the borehole.

Abstract: The displacement of a valve stem (16) is measured during diagnostic testing by temporarily mounting a laser head (112) on the valve body (18) or yoke (20), for generating a source laser beam (118) that reflects from a target (120) that moves with the stem. The timing of the reflected beam (132) returning to the head (112) relative to the projection of the source beam, gives an indication of the displacement of the stem.