Abstract: A new configuration of a pressurized water reactor nuclear fuel assembly having a disengaging upper tie plate corner portion (60) which will disengage if the fuel assembly is unintentionally lifted, thus precluding the lifting of the fuel assembly from the reactor core and thereby avoiding the potential risk of dropping the irradiated nuclear fuel assembly.

Abstract: A nuclear fuel assembly for a boiling water reactor having a spacer grid for positioning and retaining the fuel rods. The spacer grid comprising an upper grid structure and a lower grid structure. Each grid structure comprises a first set of grid strips and a second set of grid strips which intersect to form in each grid structure a lattice of rectangular and square shaped cells through which the fuel rods extend and which act against the fuel rods within the cells. The lattice in each of the upper grid structure and the lower grid structure being the same. The upper grid structure and the lower grid structure being oriented relative to one another so that each of the rectangular and square shaped cells in the upper grid structure is superimposed on a corresponding one of the rectangular and square shaped cells in the lower grid structure so as to act cooperatively against and provide support to a fuel rod on four sides of the fuel rod.

Abstract: An improved fuel rod is provided having a part-length fuel rod portion that improves performance with respect to typical part-length fuel rods without significant degradation of the benefits that are achieved by using such a system, e.g., improved fuel utilization, stability, and shut down margin. The present invention provides a fuel rod for a light water nuclear reactors that comprises a part-length fuel rod and an extension tube having at least one wall member defining an enclosed flow path therethrough, the extension tube being coupled to a portion of the part-length fuel rod so as to be disposed axially above the part-length fuel rod, and including at least one inlet opening, for allowing fluid that surrounds the rod and initially comprises a two phase mixture of steam and liquid, to enter the enclosed fluid path and at least one outlet opening located above the inlet opening, the extension tube includes means for separating at least some of the steam located in the fluid from the liquid located therein.

Abstract: A method is provided for retrofitting nuclear fuel assemblies in bottom entry fuel assembly type nuclear reactors having a transition piece to guide liquid coolant into a channel entry area. The transition piece is disposed above an entry orifice in a fuel assembly support plate. The transition piece has side walls and a multi-pronged lead-in finger. The method comprises the steps of removing the lead-in finger from the transition piece, machining internal surfaces of the side walls of the transition piece and installing an insert to be disposed within and supported by the machined transition piece.

Abstract: A moisture detection system for in-process nuclear fuel powder components includes a container within which the powder is located, a purge gas supply for providing a purge gas within the container, the purge gas contacting the powder and absorbing moisture therefrom, an off-gas line for transporting at least a portion of the purge gas after the purge gas contacts the powder and a moisture detector for determining the moisture in the purge gas. The moisture content of the purge gas provides an indication of the moisture content of the powder. A process for detecting moisture of an in-process nuclear fuel powder component includes the steps of supplying a purge gas, contacting the powder with the purge gas, transporting at least a part of the purge gas through an off-gas line, and measuring the moisture of the purge gas in the off-gas line, the moisture measurement providing a measure of moisture in the powder.

Abstract: An improved fuel rod is provided having a part-length fuel rod portion that improves performance with respect to typical part-length fuel rods without significant degradation of the benefits that are achieved by using such a system, e.g., improved fuel utilization, stability, and shut down margin. The present invention provides a fuel rod for a light water nuclear reactors that comprises a part-length fuel rod and an extension tube having at least one wall member defining an enclosed flow path therethrough, the extension tube being coupled to a portion of the part-length fuel rod so as to be disposed axially above the part-length fuel rod, and including at least one inlet opening, for allowing fluid that surrounds the rod and initially comprises a two phase mixture of steam and liquid, to enter the enclosed fluid path and at least one outlet opening located above the inlet opening, the extension tube includes means for separating at least some of the steam located in the fluid from the liquid located therein.

Abstract: A shipping shim (30) for restraining nuclear fuel rods (11, 12, 13) in a nuclear fuel assembly (10) which accommodates varied sized gaps (g.sub.1, g.sub.2, g.sub.3, g.sub.4) between fueled and non-fuel bearing members in the fuel assembly.

Abstract: An improved fuel rod is provided having a part-length fuel rod portion that improves performance with respect to typical part-length fuel rods without significant degradation of the benefits that are achieved by using such a system, e.g., improved fuel utilization, stability, and shut down margin. The present invention provides a fuel rod for a light water nuclear reactors that comprises a part-length fuel rod and an extension tube having at least one wall member defining an enclosed flow path therethrough, the extension tube being coupled to a portion of the part-length fuel rod so as to be disposed axially above the part-length fuel rod, and including at least one inlet opening, for allowing fluid that surrounds the rod and initially comprises a two phase mixture of steam and liquid, to enter the enclosed fluid path and at least one outlet opening located above the inlet opening, the extension tube includes means for separating at least some of the steam located in the fluid from the liquid located therein.

Abstract: A shoe for a bar code wand consists of an upper cylindrical portion having a through hole for receiving and frictionally engaging a portion of the scanning head of the wand, a downwardly sloping inwardly converging shoulder located within the hole near the bottom of the cylindrical portion serving to limit the extent of penetration of the wand into the hole, and a pair of parallel opposing contact arms extending downward from the bottom of the cylindrical portion, for providing a predetermined gap between the reading tip of the wand and a bar code label. The ends of the contact arms are radiused to permit angular movement within a range of the wand from perpendicular orientation with a bar code label being read by moving the assembly of the wand and shoe across the label, while maintaining the desired gap.

Abstract: A lower tie plate for a nuclear fuel assembly is provided via an integral casting including a frame containing a first plurality of guide tube bosses in a central portion thereof, a second plurality of guide tube bosses concentric with the first plurality of guide tube bosses, and a plurality of teardrop shaped struts connecting the first and second guide tube bosses to one another and to the frame. The guide tube bosses serve to respectively directly receive individual guide tube cap screws of guide tubes of the nuclear fuel assembly. The interior top portion of the lower tie plate is configured to receive and support a debris screen.

Abstract: A low pressure drop spacer for positioning and retaining the fuel rods of a nuclear fuel assembly in which a plurality of upper and lower spring forks which extend through apertures in the side wall of the spacer into the assembly and through apertures in grid members which divide the assembly. The intersection and superposition of the spring forks, side wall and grid members form fuel rod passageways through which the fuel rods extend.

Abstract: An arrangement for supporting a fuel assembly of a nuclear reactor has upper and lower reactor core support plates, upper and lower tie plates for supporting fuel rods and a coolant path through the assembly. The improvement comprises a redesigned lower tie plate for providing an upward biasing force to the assembly for forcing the upper tie plate against the upper reactor core support plate. The biasing force is in the same direction as a levitation force caused by coolant flow through the assembly. In a preferred form, the tie plate includes an upper and lower section with hold-up springs disposed between the two sections.

Abstract: A gas turbine topped onto two or more steam turbine plants having therebetween a heat recovery heat exchanger comprising two side-by-side, but separate, ducts is disclosed. Each of the ducts comprises heat exchange means for each of the respective steam turbines. The hot exhaust gases from a gas turbine are passed in heat exchange with heat exchange means for each of steam turbine. Damper means for controlling the amount of hot exhaust gas passing into the respective heat exchange means for each steam turbine are also disclosed. In another embodiment of the invention, separate damper means for each of said respective heat exchange means for varying the amount of hot exhaust gas between each of said heat exchange means are provided. The inventive system provides high plant efficiency and excellent operating flexibility.

Abstract: Methods and apparatus for improving fretting resistance of zirconium alloy components formed into a shape for use in a nuclear reactor are disclosed in which at least a portion of the outer surface of a component is reacted with material selected from the group consisting of carbon, nitrogen, oxygen and combinations of the foregoing at a temperature below about 700.degree. C. to form a wear resistant layer on the surface of the component.

Abstract: A zirconium or zirconium alloy passivation process comprises providing an electrolyte which is capable of removing nickel, nickel alloys and alloys containing nickel from the surface of a zirconium or zirconium alloy article, keeping the dissolved metal in solution while simultaneously anodizing the article surfaces. Such nickel, if not removed provides a window for hydride accumulation to occur, detrimentally affecting the alloy properties when subject to a nuclear reactor environment. An article placed in the electrolyte in proximity to a cathode and connected to a power source has the trace nickel, nickel alloys and alloys containing nickel removed to background levels and reduces the potential for hydride accumulation within the article in a nuclear reactor environment, and provides for increased article life.

Abstract: A rotary kiln has a rotatable cylinder through which a product passes in counter-current to a hot gas stream which dries the product. At the product entrance end, a vent annulus enters into the kiln for a length sufficient to allow entrained particles in the exhaust gas to either fall out within the rotating cylinder or pass through the annulus at a velocity sufficient to maintain their entrainment until discharge at a downstream location. Utilizing a vent annulus which enters into the kiln prevents entrained particles from becoming disentrained in the feed breech of the kiln which causes accumulation requiring periodic shut-downs for clean-outs which are disruptive of continuous operation. Utilizing the present invention incorporating a vent annulus in the rotary kiln minimizes down time and increases the efficiency and utilization of the rotary kiln. Additionally, the Separate vent annulus substantially simplifies the feed breech structure of the kiln simplifying construction.

Abstract: A boiling water reactor fuel rod assembly is provided having a plurality of fuel rod spacers which are slidably receivable within an outer channel. Each of the rod spacers is formed of at least one lattice which defines a plurality of fuel rod retaining cells. The lattice is constructed of a plurality of pairs of oppositely facing springy support strips, with each support strip having a plurality of spring-loaded indentations. In an unloaded condition, oppositely facing indentations of each pair of strips, which define each cell, are displaced closer to one another. In a loaded condition, the oppositely facing cell indentations are forced away from each other by the fuel rods so that the springloaded indentations support and retain the fuel rods.

Abstract: A fuel assembly for a boiling water nuclear reactor is provided comprising an elongated central water channel including wall members that define an enclosed fluid flow path therethrough, the channel includes a lower opening for receiving water and allowing water to flow through the fluid flow path and at least one outlet opening. At least one partial water rod is provided that is coupled to a partial fuel rod so as to be disposed axially above the partial fuel rod. The partial water rod includes an inlet opening in fluid communication with the outlet opening of the central water channel so as to allow water to flow from the water channel into an interior of the partial water rod.

Abstract: A spacer sleeve for positioning and restraining a nuclear fuel rod in a nuclear fuel assembly, having a thin walled tubular member having an inner wall and an outer end, and extending a height from a lower end to an upper end and being positioned around the fuel rod to form an unrestricted coolant flow passage along the height of the tubular member, the flow passage having a cross-sectional flow area formed between the fuel rod cladding and the inner wall of the tubular member, and a thin tab extending from the tubular member into the unrestricted flow area and secured to a portion of the cladding of the fuel rod.

Abstract: A nuclear fuel assembly for a light water reactor includes an axially directed shortened water channel, truncated between an uppermost spacer and an upper tie plate. A boat-tail shaped end fitting is mated to the truncated end of the water channel, with their mated outer surfaces forming a smooth tangential substantially continuous surface therebetween. Opposing outer side surfaces of the end fitting are substantially convex, and inwardly tapering toward one another in a continuously curved manner, with the side surfaces terminating to form a top aperture. The aperture provides for the exit of coolant moderator from the water channel, and is sized to equalize the internal flow velocity of coolant moderator exiting from said aperture to the external coolant moderator flow velocity at said aperture.