Abstract: A ring latched coupler includes a male assembly having a plurality of grooves and a female assembly having a plurality of slots. The female assembly is configured to receive the male assembly. A latching ring is rotatably carried by the female assembly. The latching ring is configured such that upon rotation of the male and female assemblies relative to the latching ring, portions of the latching ring extend through the slots in the female assembly to engage grooves in the male assembly.

Abstract: A rack for holding a plurality of tools includes a plate member having openings for receiving tools, detent pins for releasably securing the plate member to a surface, detent clips associated with each opening for releasably securing a tool within the associated opening and pin members associated with each opening for interacting with a tool using device to permit engagement and disengagement of the tool to the tool using device.

Abstract: A fiberscope inspection system for a nuclear steam generating plant includes an optical unit and a transport unit respectively coupled to opposite ends of the fiberoptic cable and mounted at spaced-apart points on a trolley beneath the tube sheet, with the fiberoptic cable hanging freely in a catenary between the two units, both of which are coupled by cable to a remote control station. The optical unit is self-contained and includes a light source, a video camera and a focusing mechanism and chain and sprocket remotely-controlled drive means for controlling the focusing mechanism. The transport unit includes a cartridge comprising a coil of a steel drive tape, the leading end of which is welded to a split-sleeve coupling disposed in clamping engagement with the leading end of the fiberoptic cable, the tape being engageable by a drive sprocket for driving same to feed and retract the fiberoptic cable. Position sensing means are provided for monitoring the position of the fiberscope probe.

Abstract: A method of rapidly retubing a steam generator while it is vertically oriented in a containment vessel and keeping the level of radiation to which workmen are subjected at a minimal level.

Abstract: Described is a movable work station apparatus including travelling-hoist supported tools and a vertically and rotarywise movable frame-carried radiation-shielded enclosure, or gondola, for working personnel involved in tube-bundle-replacement tasks performed within the shell of a steam generator in a nuclear plant. The enclosure, or gondola, is divided and accommodates four upright workers in mutually-facing pairs at opposite sides of a work-accommodating clearanceway observable and accessible from the gondola interior via lead glass windows and hand holes.

Abstract: Modular bundles of U-shaped tubes having primary fluid conduits with compression seals which cooperate with a pair of transversely disposed parallel support plates to allow removal and replacement of the modular tube bundles to facilitate maintenance and extend steam generator life in pressurized water reactors.

Abstract: A system and method for retubing a steam generator for a pressurized water reactor while the steam generator is in place in a containment vessel.

Abstract: There is disclosed a method for rapid refueling of a nuclear reactor. The upper package including the head and upper internals and control rods of the reactor includes a missile shield and by engagement with the shield is moved to a refueling position in a single lifting operation exposing the core in the lower package. The fuel assemblies are then replaced. The removal of the control rods from the core with the upper package is compensated for by an increase in the concentration of neutron absorber, such as boron including B.sup.10, in the medium in which the core is immersed. Typically, the refueling can take place in a few days, at intervals of two to six months. During refueling a fraction of the assemblies are replaced. Because of the facility for rapid refueling and consequent lower time cycle for refueling, the fuel can be of low enrichment and the concentration of neutron absorber in the reactor coolant medium can be decreased.

Abstract: A method and apparatus for protecting fuel rods in a nuclear reactor core under conditions of a major break in the coolant inlet piping connected to the reactor inlet nozzle. A multi-venturi protector which includes multiple parallel dislosed venturies is mounted in the inlet nozzle. The characteristics of the venturi protector are such that coolant flow through the protector into the reactor is unimpeded, but reverse flow through the protector is restricted when a break occurs in the inlet piping. The resistance offered to such reverse flow permits reactor coolant and emergency core coolant to remain in contact with the reactor core for a time sufficient to allow the fuel rods to decrease in temperature to a low safe level.

Abstract: A nuclear reactor is disclosed wherein hydraulic drive mechanisms for control rods are provided with a positive mechanical latching arrangement to maintain the control rods in a withdrawn position with respect to the core. With this arrangement, the coil of an associated electromagnet must be deliberately energized in order to insert the control rod into the core thus making accidental tripping highly unlikely. The drive mechanism is further provided with a hydraulic decelerating device which uses reactor coolant water to smoothly decelerate the control rod as it approaches the fully withdrawn position.

Abstract: A nuclear reactor internals arrangement is disclosed which facilitates reactor refueling. A reactor vessel and a nuclear core is utilized in conjunction with an upper core support arrangement having means for storing withdrawn control rods therein. The upper core support mounted to the underside of the reactor vessel closure head so that upon withdrawal of the control rods into the upper core support, the closure head, the upper core support and the control rods are removed as a single unit thereby directly exposing the core for purposes of refueling.

Abstract: Upon the occasion of loss of coolant in a nuclear reactor as when a coolant supply or return line breaks, or both lines break, borated liquid coolant from an emergency source is supplied in an amount to absorb heat being generated in the reactor even after the control rods have been inserted. The liquid coolant flows from pressurized storage vessels outside the reactor to an internal manifold from which it is distributed to unused control rod guide thimbles in the reactor fuel assemblies. Since the guide thimbles are mounted at predetermined positions relative to heat generating fuel elements in the fuel assemblies, holes bored at selected locations in the guide thimble walls, sprays the coolant against the reactor fuel elements which continue to dissipate heat but at a reduced level.

Abstract: A system is provided for determining during operation of a nuclear reactor having fluid pressure operated control rod mechanisms the exact location of a fuel assembly with a defective fuel rod. The construction of the reactor internals is simplified in a manner to facilitate the testing for defective fuel rods and to reduce the cost of producing the upper internals of the reactor.

Abstract: 5. A grid structure for a nuclear reactor fuel assembly comprising a plurality of connecting members forming .[.at least one.]. longitudinally extending .[.opening.]. .Iadd.peripheral and inner fuel element openings .Iaddend.through .Iadd.each of .Iaddend.which .Iadd.openings .Iaddend. at least one nuclear fuel element extends, said connecting members forming wall means surrounding .[.said.]. .Iadd.each peripheral and inner fuel element .Iaddend.opening, a pair of rigid projections .Badd.longitudinally spaced from one another .Baddend.extending from a portion of said wall means into .[.said.]. .Iadd.each peripheral and inner .Iaddend.opening for rigidly engaging .[.said.]. .Iadd.each .Iaddend.fuel element, .Iadd.respectively, yet permit individual longitudinal slippage thereof, .Iaddend.and resilient means .Badd.formed integrally on and from said wall means and .Baddend.positioned in .[.said.]. .Iadd.each peripheral and inner .Iaddend.