Abstract: A valve assembly includes a flange connected to a vessel penetration of a reactor pressure vessel of a nuclear reactor. A valve is disposed inside the flange or protrudes from the flange into the vessel penetration. The valve includes a valve seat and a movable valve member positioned so that pressure inside the reactor pressure vessel urges the movable valve member against the valve seat to close the valve. The valve assembly further includes a plenum having an inlet via which the plenum can be pressurized to apply pressure to the movable valve member that urges the movable valve member away from the valve seat to open the valve. The plenum may be defined in part by a surface of the movable valve member. The valve assembly preferably does not include a valve actuator.

Abstract: A nuclear reactor includes a reactor core comprising fissile material disposed in a reactor pressure vessel. A radiological containment contains the nuclear reactor. A containment compartment contains the radiological containment. A heat sink includes a chimney configured to develop an upward-flowing draft in response to heated fluid flowing into a lower portion of the chimney. A fluid conduit is arranged to receive fluid from the containment compartment and to discharge into the chimney. A filter may be provided, with the fluid conduit including a first fluid conduit arranged to receive fluid from the containment compartment and to discharge into an inlet of the filter, and a second fluid conduit arranged to receive fluid from an outlet of the filter and to discharge into the chimney. As the draft is developed passively, there is no need for a blower or pump configured to move fluid through the fluid conduit.

Abstract: A nuclear reactor is surrounded by a reactor radiological containment structure. Depressurization lines running from the reactor automatically vent the reactor to the containment structure or to a compartment in the containment structure when a low pressure condition exists in the reactor. The depressurization lines include biased-open passive valves and actively actuated isolation valves arranged in series.

Abstract: A nuclear reactor comprises a pressure vessel containing a nuclear reactor core. A reactor core cooling system comprises a standpipe including a plurality of orifices in fluid communication with a refueling water storage tank (RWST) to drain water from the RWST into the standpipe, and an injection line configured to drain water from the standpipe to the pressure vessel. In some embodiments the standpipe is disposed in the RWST, while in other embodiments the standpipe is disposed outside of the RWST and cross-connection pipes connect the plurality of orifices with the RWST. The reactor core cooling system may further comprise a valve configured to control flow through one orifice of the plurality of orifices in fluid communication with the RWST based on water level in the standpipe. The valve may comprise a float valve having its float disposed in the standpipe.

Abstract: A valve for controlling flow of high pressure fluid to a CRDM hydraulic latching mechanism of a nuclear reactor core. The valve includes a valve body having an inlet for receiving fluid from a fluid source, an outlet, and a dump port for dumping fluid backflow. A valve member is movable within the valve body between a first position restricting flow between the outlet and the dump port such that high pressure fluid entering the valve body through the inlet exits the valve body through the outlet, and a second position whereat the dump port is in fluid communication with the outlet such that at least a portion of any backflow fluid flowing back into the valve body via the outlet exits the valve body via the dump port.

Abstract: A nuclear reactor comprises a nuclear reactor core disposed in a pressure vessel. An isolation valve protects a penetration through the pressure vessel. The isolation valve comprises: a mounting flange connecting with a mating flange of the pressure vessel; a valve seat formed into the mounting flange; and a valve member movable between an open position and a closed position sealing against the valve seat. The valve member is disposed inside the mounting flange or inside the mating flange of the pressure vessel. A biasing member operatively connects to the valve member to bias the valve member towards the open position. The bias keeps the valve member in the open position except when a differential fluid pressure across the isolation valve and directed outward from the pressure vessel exceeds a threshold pressure.

Abstract: An unirradiated nuclear fuel assembly component transport system that includes a clamshell-type inner liner that opens along its axial dimension to load and unload the fuel component being transported. The exterior dimensions of the liner conform to a generic overpack tubular container. The overpack is separable into an upper and lower section with the lower section having a V-shaped channel extending along its longitudinal axis. The liner is supported in the V-shaped channel by at least one row of shock mounts on either side of the channel. The lower section of the overpack is secured from rotation and the top section is latchably engaged to the lower section of the overpack.

Abstract: A thermally integrated burner/emitter/recuperator (BER) for a thermophotovoltaic (TPV) electric generator achieves improved energy efficiency using either liquid or gaseous fuels. A mixed ceramic and metallic alloy heat exchanger, together with a high temperature emitter, achieves increased energy density in a compact and lightweight assembly.

Abstract: A solar rocket for propelling and powering the electronics of a spacecraft includes a black body cavity of thermal storage material. Propulsion tubes and a connected nozzle axially extend through the black body cavity for burning propellant in order to provide thrust for the rocket. An insulation sleeve is removably located at the outer periphery of the cavity of thermal storage material. Energy conversion diodes surround the insulation sleeve. The thermal storage material, the insulation sleeve and the energy conversion diodes form a receiver. The receiver has a pair of spaced apart holes therethrough which lead into an interior space of the black body cavity in order to receive sunlight. A mirror assembly is located near each hole of the receiver for harnessing sunlight and providing radiant energy through the holes into the internal space of the black body cavity.

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 thermionic reactor for providing electrical power and propulsion power. A reactor vessel has a plurality of thermionic heat pipe modules located therein and spaced apart on a hexagonal pitch. Nuclear fuel elements are positioned in the spaces between the thermionic heat pipe modules. Insulating material is provided between the reactor vessel and the array of thermionic heat pipe modules and nuclear fuel elements. Propulsion power is provided by a propellant storage tank and propellant nozzle in fluid communication with opposite ends of the reactor vessel. The thermionic heat pipe modules serve to produce electricity and aid in removal of waste heat.

Abstract: A gas cooled nuclear fuel element. A cylindrical tube having an open lower end contains nuclear fuel disks stacked one upon the other to define an annular space between the tube and disks. An upper and a lower end fitting in the tube support the stack of fuel disks. Each disk has an axial bore or channel for coolant flow. The disks may also be provided with grooves extending radially on the upper or lower face from the axial channel to the outer edge of each disk. The lower end fitting has a central bore that is coaxial with the axial channel in the disks. Coolant flows into the annular space, radially between disks, and then axially out the disks and lower end fitting.

Abstract: A nuclear fuel element for a particle bed reactor. Concentric inner and outer porous cylinders attached at either end define an annulus therebetween that contains a fuel particle bed of nuclear fuel material. The outer porous cylinder is provided with fins that extend radially outward along its entire length. A nonporous cylinder is attached to the outer porous cylinder at either end and is positioned around the outer porous cylinder so as to be concentric therewith. Flexible fins extend radially inward form the nonporous cylinder along its entire length and contact the fins on the outer porous cylinder for conduction of heat to heat removal tubes on the outer surface of the nonporous cylinder. The heat removal tubes allow bimodal cooling of the particle bed reactor.