Abstract: A tube support structure for a helically coiled fluid heat exchanger including a plurality of support strips interconnected by a plurality of support members. Two tubes are nested between support members against a support strip, a spring plate is placed over the tubes and a second strip is pressed on the assembly to the desired spring pressure and affixed.

Abstract: A steam generator tube support structure having three sets of mutually parallel strips each set extending in a different direction oriented sixty degrees from the other two. One set of strips is slotted at both edges. The other two sets of strips are slotted on one edge. The strips engage to form hexagonal cells for supporting and aligning a triangular array of tubes. Dimples in the strips provide point tube support.

Abstract: A typical embodiment of the invention provides a nuclear fuel assembly lock structure for control rod guide tubes. Illustratively, a sleeve telescopes over an end portion of a control rod guide tube which bears against an internal shoulder of the tube. The upper end of the sleeve protudes beyond the control rod guide tube spider and is locked in place by means of a resilient cellular lattice or lock that is seated in a mating groove in the outer surface of the sleeve. A special tool is provided for disengaging the entire lock structure, washer, spider, spring and grill from the end of the fuel assembly in order to enable these components to be removed in an assembled state and subsequently replaced on the fuel assembly after inspection and repair.

Abstract: A tube support structure for a helically coiled fluid heat exchanger including a plurality of support strips interconnected by a plurality of support members. Two tubes are nested between support members against a support strip, a spring plate is placed over the tubes and a second strip is pressed on the assembly to the desired spring pressure and affixed.

Abstract: A typical embodiment of the invention provides a nuclear fuel assembly lock structure for control rod guide tubes. Illustratively, a sleeve telescopes over an end portion of a control rod guide tube which bears against an internal shoulder of the tube. The upper end of the sleeve protrudes beyond the control rod guide tube spider and is locked in place by means of a resilient cellular lattice or lock that is seated in a mating groove in the outer surface of the sleeve. A special tool is provided for disengaging the entire lock structure, washer, spider, spring and grill from the end of the fuel assembly in order to enable these components to be removed in an assembled state and subsequently replaced on the fuel assembly after inspection and repair.

Abstract: This invention relates to a group of modular heat exchangers of the type having a steam chamber, a feedwater chamber, and a feedwater tube passing through the steam chamber to establish fluid communication with the feed chamber.

Abstract: A nuclear fuel assembly includes guide tubes having integral ridges oriented and spaced to increase coolant flow in the gap between the guide tubes and adjacent fuel elements.

Abstract: A typical embodiment of the invention combines a novel cellular end fitting for a nuclear reactor fuel assembly with a new design for a fuel rod end cap and a radiation sensing device probe to provide a means for swiftly and accurately distinguishing sound fuel rods from those rods that have developed leaks. For example, a somewhat thinner than usual fuel rod end cap is accessible through the open cellular structure of the end fitting to permit a hollow metal probe to contact the fuel rod end cap. This direct contact excludes most of the water, metal and other shielding materials from the volume between the interior of the fuel rod and the radiation detector, thereby improving the quality of the fuel rod examination. A bridge and trolley structure for accurately positioning the probe also is described.

Abstract: An improved containment for radiation shielding and pressure suppression is presented. The arrangement, which is particularly suited for marine propulsion application, includes, in a preferred embodiment, a double wall containment shell including water as a biological shield, a divided wet well arrangement and means for precluding discontinuity of the radiation shielding effect due to shifting of the liquid in the wet well at various ship attitudes.

Abstract: A typical embodiment of this invention provides a hydraulic mechanism for alleviating the effect of seismic forces and other stresses that are applied to a fuel assembly in a nuclear reactor. Illustratively, hollow guide posts protrude into a fuel assembly end fitting grid from biased spring pads. Plungers that move with the spring pads plug one end of each of the respective guide posts. Plates on the end fitting grid that have individual holes for fluid discharge partially plug the other ends of the respective guide posts, thereby providing a hydraulic means for absorbing the longitudinal component of seismic shocks and other anticipated forces.

Abstract: A typical embodiment of the invention provides a nuclear fuel assembly lock structure for control rod guide tubes. Illustratively, a sleeve telescopes over an end portion of a control rod guide tube which bears against an internal shoulder of the tube. The upper end of the sleeve protrudes beyond the control rod guide tube spider and is locked in place by means of a resilient cellular lattice or lock that is seated in a mating groove in the outer surface of the sleeve. A special tool is provided for disengaging the entire lock structure, washer, spider, spring and grill from the end of the fuel assembly in order to enable these components to be removed in an assembled state and subsequently replaced on the fuel assembly after inspection and repair.

Abstract: An illustrative embodiment of the invention discloses a technique for disassembling a nuclear reactor fuel element without destroying the individual fuel pins and other structural components from which the element is assembled. A traveling bridge and trolley that span a water-filled spent fuel storage pool support a strongback. The strongback is under water and provides a working surface on which the spent fuel element is placed for inspection and for the manipulation that is associated with disassembly and assembly. To remove, in a non-destructive manner, the grids that hold the fuel pins in the proper relative positions within the element, bars are inserted through apertures in the grids with the aid of special tools. These bars are rotated to flex the adjacent grid walls and, in this way relax the physical engagement between protruding portions of the grid walls and the associated fuel pins.

Abstract: This invention is directed toward a nuclear fuel assembly guide tube arrangement which restrains spacer grid movement due to coolant flow and which offers secondary means for supporting a fuel assembly during handling and transfer operations.

Abstract: An illustrative embodiment of the invention has one or more corrugations formed in the surface of a fuel element grid for a nuclear reactor. Not only does the corrugation enhance the strength of the grid plate in which it is formed, but it also provides a simple and convenient means for regulating the reactor coolant pressure drop through an appropriate choice of the corrugation depth.

Abstract: A spacer grid for a nuclear fuel assembly is comprised of a lattice of grid plates forming multiple cells that are penetrated by fuel elements. Resilient protrusions and rigid protrusions projecting into the cells from the plates bear against the fuel element to effect proper support and spacing. Pairs of intersecting grid plates, disposed in a longitudinally spaced relationship, cooperate with other plates to form a lattice wherein each cell contains adjacent panels having resilient protrusions arranged opposite adjacent panels having rigid protrusions. The peripheral band bounding the lattice is provided solely with rigid protrusions projecting into the peripheral cells.

Abstract: A typical embodiment of the invention provides a fitting for stabilizing the burnable poison rods and the like within a nuclear reactor fuel element. An illustrative orifice rod assembly fitting is assembled inexpensively from stamped metal strips which expose the ends of the fuel rods within the fuel element for inspection and simplify rearrangement of partially used fuel elements within a reactor core.

Abstract: A typical embodiment of the invention has an array of sockets that are welded to the intersections of the plates that form the upper and lower end fittings of a nuclear reactor fuel element. The sockets, which are generally cylindrical in shape, are oriented in directions that enable the longitudinal axes of the sockets to align with the longitudinal axes of the fuel rods that are received in the respective sockets. Detents impressed in the surfaces of the sockets engage mating grooves that are formed in the ends of the fuel rods to provide for the structural integrity of the fuel element.

Abstract: The invention provides means for inserting tubular members into a grid structure without mutual contact between the tubular members. After the tubular members are inserted, a movable strap is slid into position, thereby engaging, locating, and supporting the tubular member in a fixed location.

Abstract: A grid structure for holding a plurality of nuclear fuel rods. The grid structure is of the type having wall means, including rigidly interconnected generally rectangular metal strips, forming a plurality of passageways and adapted to support nuclear fuel rods within some of the passageways. The improvement comprises providing elongated slots intermediate and normal to the longitudinal edges of each of the strips at each intersection of the strips whereby the slots form openings in each corner of each passageway.

Abstract: This invention relates to an improved system of providing power having a unique generating means of the nuclear reactor variety adapted with a plurality of steam generators in the form of replaceable modular units of the expendable type for the attainment of the optimum in effective and efficient vaporization of fluid during the process of generating power.