Abstract: A hydrogenous moderated thermionic nuclear reactor operating in the thermal neutron energy region. Thermionic fuel elements are formed from multiple concentric cylinders. The center cylinder is a combination heat pipe and thermionic converter collector. The second cylinder is the converter emitter. The third cylinder is the nuclear fuel. The outer cylinder is the physical barrier between the fuel element and moderator. Between the outer radius of the fuel and outer cylinder is a gap containing multi-foil insulation. The insulation acts as a thermal barrier between the fuel and the outer cylinder and accommodates fuel expansion. This also causes heat flow to be radially inward from the fuel to the center converter/heat pipe.

Abstract: A transport and storage cask for spent nuclear fuel. A cask body having one open end receives a basket in such a manner so as to maintain a steady state gap between the cask body and basket. Centering keys on the cask body and basket provide the centering function. For ease of manufacture, the basket is formed from multiple layers of rowed carbon steel plates that have complementary grooves in their mating surfaces to form fuel cell channels when the plates are assembled together. Bands are attached together around the plates at narrowed diameter portions on the plates to hold the plates in their assembled position. The gap between the basket and cask body allows the cask to withstand a fire transient without transmitting heat from the fire into the basket.

Abstract: A weld fixture for receiving and aligning the fuel rod contact points of a nuclear fuel bundle spacer grid. Two plates are provided with intersecting unequally spaced slots that define polygons on one side of each plate. Both plates have bores therethrough substantially at the slot intersections and in the slots adjacent the outer edges of the plates. Bores are provided through both plates in polygons that correspond to fuel assembly guide tube and instrument tube locations. These positions receive guide cell pins during use, some of which are hollow and are used to bolt the plates together over the spacer grid strips. Bores in each plate through the defined polygons receive alignment pins. Guide rods receive and align the plates through corner bores in each plate. The slots and pins in the facing plates align the critical fuel rod contact points in the spacer grid during the intersection welding process.

Abstract: A modular grid welding fixture for a spacer grid that facilitates full grid laser welding of a spacer grid in one setup. The modular design allows for partial implementation of each weld type. A base plate is used for mounting to the positioning/rotational plate of the welding system. A removable sub-plate received in the base plate is used to position the grid strips for proper location for welding. A top fixture plate is aligned with the base plate and provides for mounting of a second sub-plate if required. Side plates with spring loaded pressure pads that are hinged to the top fixture plate apply uniform pressure to the outer grid strips during processing. The base plate, top plate, side plate, and pressure pads are provided with a plurality of through holes to allow access of the laser beam for welding. Corner clips are used to insure contact of the overlapping sections of the outer grid strips for proper corner welding.

Abstract: A preinstalled, adjustable conductor guide for offshore platforms. A conductor guide is provided with apertures spaced around its circumference. A rectangular tube is rigidly attached to the conductor guide at each aperture such that the tube extends upwardly from the conductor guide at an angle. The tube is provided with a plurality of offset slotted holes along its length on opposing sides. A slide having a plurality of offset holes along its length is received in the tube and movable between a first retracted position and a second inserted position. A bolt, received through the holes in the tube and slide, and nut are used to retain the slide in either the first or second position.

Abstract: A nuclear reactor and emergency core cooling system. A nuclear reactor is provided with a cylinder around the core barrel that defines an annular channel therebetween. An injection nozzle is provided through the reactor vessel for delivery of emergency coolant to the defined channel. Emergency coolant is supplied during a LOCA to the injection nozzles sequentially from a high pressure tank, a low pressure tank, gravity feed tanks inside the reactor building, and from sumps that collect coolant in the reactor building. Check valves in the upper portion of the cylinder vent steam to the reactor inlet lines during a LOCA. Bores around the upper circumference of the cylinder break any siphoning action that might occur at the injection nozzle if there is a break in the emergency coolant lines from the emergency coolant sources.

Abstract: An apparatus for producing useful energy from the potential energy stored in a deep body of water using tidal and/or wave forces. A hollow base supported above the sea bottom slidably receives a piston therein. A first cylinder is rigidly attached at its lower end to the piston and at its upper end to a floating structure so that the floating structure and piston move vertically in response to wave and/or tidal action and which can be fixed at any position therealong by locking pins. The base is provided with one-way valves on its upper and lower end that only allow water to exit the base through the valves. Water enters the base through a one-way valve in the first cylinder and a tube in the first cylinder. A turbine positioned in the tube is driven by the water as it travels through the tube. The turbine drives a power generator.

Abstract: A spent nuclear fuel shipping basket. A shell has a lower wall section of greater thickness than the remainder of the shell and a plurality of notches spaced apart around its inner circumference and extending the length of said shell. A plurality of drain holes are provided in the lower end plate of the shell. A plurality of cruciforms are sized to receive fuel cans. The cruciforms are formed from a neutron absorber and heat transfer material. Ring supports are spaced apart along the length of the shell and receive and transfer operating loads from the fuel cans to the shell and the shipping cask that receives the basket.

Abstract: An integral reusable locking arrangement between the guide tube and upper end fitting of a reconstitutable fuel assembly that eliminates all loose fastener components at the reactor site. A retainer sleeve is fabricated as an addition to or part of the upper end sleeve of the guide tube assembly. The retainer sleeve is formed from a cylindrical tube that has a plurality of flexible tabs spaced around the circumference of the tube at the lower end and substantially at the mid section of the tube. The lower tabs serve to center the guide tube in a hole in the upper end fitting or top nozzle. The mid section tabs extend beyond the shoulder of a counterbore in the hole in the upper end fitting or top nozzle and serve to retain the guide tube and upper end fitting in the installed position. A sleeve or collet may be inserted into the counterbore to force the tabs inward and unlock the retainer and guide tube from the upper end fitting.

Abstract: A nuclear fuel assembly lower end fitting. Two plates each having a network of diagonal and lateral ribs in conjunction with hubs for the guide thimble hole pattern are provided. The pitch between ribs corresponds to one-half of the fuel rod pitch. This allows for the fuel rods to be supported by every other rib. One plate is rotated horizontally ninety degrees relative to the other plate so that the lateral ribs of the plates are at right angles. A screen formed from approximately 0.03 inch diameter wire with 0.100 inch pitch is provided with guide tube bosses. The plates and screen are rigidly attached to each other to form a debris filtering lower end fitting.

Abstract: An integral, reusable locking arrangement between the guide tube assembly and upper end fitting of a reconstitutable fuel assembly that eliminates all loose fastener components at the reactor site. A retainer sleeve is fabricated to cooperate with the upper end sleeve of the guide tube assembly. Slots adjacent to the upper end of the sleeve receive rigid tabs on the upper end sleeve to hold the retainer sleeve and upper end sleeve together. The retainer sleeve is formed from a cylindrical tube that has a plurality of flexible curved tabs spaced around the circumference of the tube substantially at the mid section of the tube. Optional lower tabs serve to center the guide tube assembly in the upper end fitting and provide a more rigid connection. The mid section tabs are received against the shoulders of slots provided along the walls of the hole in the upper end fitting and serve to retain the guide tube assembly and upper end fitting in the installed position.

Abstract: A nuclear reactor vessel cavity seal plate. An annular support plate is positioned over the cavity between the reactor vessel and the shield structure and seal welded to the shield structure. Inner and outer support rings attached to the annular plate are supported by the existing beams in the annular cavity. A U-shaped flexible annular expansion ring positioned between the annular plate and reactor vessel flange has its inner diameter seal welded to the reactor vessel flange and its outer diameter seal welded to the annular plate. Ports in the annular plate provide access to nuclear instruments below the annular plate. A cover plate is removably attachable to each port to seal the ports. A closable drain is provided in the annular expansion ring. This provides a permanent seal plate that allows flooding of the cavity for refueling with it being necessary to remove only the cover plates for normal reactor operations.

Abstract: A system for automatically tracking a surface for performing a welding operation comprises a frame and pair of ring gears movably mounted to the frame. The ring gears are spaced apart from each other. Three weld heads are movably mounted to each ring gear. Each weld head has a welding torch for providing a weld and a laser scanning device for scanning a surface and for measuring distances over the surface. A control system communicates with the laser scanner for receiving the measured distances and for controlling the movement of the ring gears and the weld heads.

Abstract: A tool for remotely obtaining an impression of a component surface. A support pole is used to position a mold plate having side walls against a component surface. One or more locating guides are provided with seals for sealing off bores in the component surface. A piston from a pneumatic cylinder attached to the support pole is used to force impression material into the space between the mold plate and component surface. An adhesive plate on the mold plate insures removal of the impression with the mold plate once the impression material has hardened. The surface condition of the component may be determined by inspection of the negative impression.

Abstract: A passive cooling system for removing decay heat from an open cycle nuclear reactor. Coolant tanks are filled with coolant during normal operation of the reactor and coolant pump. A check valve in the inlet line for each tank prevents loss of coolant through the inlet line. After the reactor is shut down and the coolant pump is inoperative, coolant flows from the coolant tanks through exhaust lines into the normal coolant line and to the reactor for removal of decay heat. A flow control valve or fixed orifice in the exhaust line for each tank provides for a different predetermined flow rate of coolant from each tank to match the decay heat rate of the reactor.

Abstract: A method for joining modules of ships. Ship modules are fabricated in individual bays of fabrication buildings and then moved out of the buildings for attachment together to form the ship on water. This eliminates the need for large dry docks or launch areas. The modules are floated and positioned such that the edges to be joined are adjacent or abutting each other. A flexible strap may be positioned tightly against the joint exterior to prevent water entry or a floating structure may be positioned under the modules such that a circular cross section backing seal the joint to prevent water entry. The interior of the modules is dewatered and the modules are then welded together. The modules may be positioned adjacent each other above the waterline through the use of a barge and dry dock to eliminate the need for dewatering.

Abstract: A support base has adjustable slides mounted thereon. A cam arm is mounted at one end on a piston rod that is used to cause vertical movement of the cam arm. The opposing end of the cam arm has a bore that rotatably receives a sleeve therein. An electrode holder is pivotally mounted in the sleeve such that one end of the electrode holder extends beyond the end of the sleeve. The electrode holder is movable between a first normal working position and a second non working position that corresponds to movement of the cam arm. A drive motor and belt are engaged with the sleeve to cause rotation of the sleeve, electrode holder, and electrode to perform machining operations on a workpiece that the electrode is inserted into.

Abstract: An apparatus for removing sludge from the tubes and tubesheet of a steam generator. A support structure is adapted to be mounted at an access port of a steam generator. A lance tube extends from the support structure into the steam generator. A spool attached to a high pressure hose is received in the lance tube. A pinch roller assembly mounted on the support structure is used to move the cylinder through the lance tube. High pressure water flows through slots drilled in the spool and out holes in the lance tube against the tubes and tubesheet. A rocker motor causes back and forth rotation or rocking of the lance tube to create a sweeping action. The lance tube may also be adjusted axially to insure that the water streams are directed to the tube lanes.

Abstract: A shipping container for highly enriched uranium. A heavy duty drum containing insulation material forms an outer container. Fiberboard and plywood form the insulation material and are shaped and sized to closely receive an inner container formed from stainless steel. The inner container has a closure lid that is bolted on and forms a seal through the use of O-rings.

Abstract: A spacer grid for a nuclear fuel assembly. A plurality of metal strips are interleaved on edge to define a plurality of individual cells. Each cell is sized to receive a single nuclear fuel rod. A series of projections, grid mixing vanes, extend from one edge of each metal strip and are alternately bent to extend on opposite sides of the metal strip. The alternating projections provide four grid mixing vanes that extend into each individual cell.